Keep Those Manuals Handy: Rules for Owner-Performed Maintenance

Keep Those Manuals Handy: Rules for Owner-Performed Maintenance

As an aircraft owner and pilot, you can legally perform some maintenance tasks, but you must adhere to strict guidelines when doing so. Steve Ells walks us through packing wheel bearings, while highlighting what’s important to stay legal.

As most readers of Cessna Flyer know by now, all aircraft maintenance tasks must be overseen or performed by an appropriately-rated person. For maintenance tasks, this means an A&P mechanic—or a technician, as some like to be called these days—is frequently both performing and signing off on the work. This mechanic must (by regulation) have up-to-date versions of the appropriate manuals, bulletins, tools and equipment necessary to complete the tasks. 

However, there are also a number of maintenance tasks that owners may legally perform. These are termed preventive maintenance (PM) tasks. There’s a long list of them in Appendix A of FAR 43. 

What is considered preventive maintenance?

Appendix A is titled, “Major Alterations, Major Repairs and Preventive Maintenance.” Paragraph (c) lists preventive maintenance tasks. Type “Appendix A of Part 43” into your favorite search engine (or find the link in Resources on Page 35. —Ed.).

There is a surprisingly long list of tasks allowed. For instance, owners are permitted to remove and replace batteries, replace bulbs, reflectors and lenses of position and landing lights, and replace prefabricated fuel lines. 

They can also remove and replace panel-mounted communications and navigations receivers and update databases in panel-mounted avionics such as GPS navigators. 

Great news, right? It is, especially if a pilot has the time and a place to do these tasks. The potential for saving money exists, but much more important is the satisfaction to be gleaned from learning how to take care of your own airplane. (For further reading, see the sidebar on Page 34. —Ed.)

Are you permitted to perform preventive maintenance tasks?

FAR 43.3 paragraph (g) says that “…the holder of a pilot certificate issued under Part 61 may perform PM on any aircraft owned and operated by that pilot which is not used under Part 121, 129 or 135 of this chapter.” 

So, according to this section, if the owner and pilot is not using his airplane for hire, whether on a scheduled service, an on-demand service or as a foreign carrier operating for hire in the U.S., he/she can perform PM.

But there’s a catch. It’s in 43.13. It’s titled “Performance Rules (General).”

 43.13 Performance Rules (General)

The following three points—from paragraphs (a) and (b) of the performance rules—have been abbreviated to simplify the important points the maintenance performance rules for owners. 

1. Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator.

2. He shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. 

3. Each person maintaining or altering, or performing preventive maintenance, shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness).

In other words, if you’re going to do PM, you must follow the procedures in the manuals. It’s as simple as that. 

It’s important at the outset to understand that airplane maintenance, while seeming to be like automobile or other gas engine maintenance in that it must be done right, is different in a very important way. In airplane maintenance, there is a published protocol for every operation, even the tightening of a nut or bolt. 

Another peculiar-to-aircraft trait is this: the strength versus weight equation must always be kept at the forefront of every operation and decision. In other words, if you believe that more is better, whether it be the size of a bolt or the amount of torque, you’re going to do more harm than good. 

Gathering the manuals and bulletins to meet the requirements of the FARs is much easier and less expensive than it used to be. The secret is the internet. Manufacturers have come to realize that making their manuals and bulletins available at no cost or consolidating a double-shelf full of manuals onto a CD is a sound idea, simply because access to manuals makes it much easier for maintenance shops (especially smaller shops) to access the precise methods and techniques the manufacturer has developed for maintaining its product. 

So, step one for owners that want to start working on their airplanes is to have or have access to manuals, and either have the tools or be able to manufacture the tools required to properly perform each maintenance task. 

Let’s look at an example of why manuals are important.

Greasing wheel bearings: a “simple” preventive maintenance task

Greasing the wheel bearings on an airplane may seem simple. At its most basic, it can be described in the following steps: First, jack up the airplane or axle enough to get the tire off the ground, then remove the axle nut and pull the wheel/tire assembly off the axle. Next, remove each bearing, clean it and the bearing race, inspect for damage or corrosion, replace if necessary, pack with grease and reinstall. Finally, reinstall the tire/wheel assembly, tighten the axle nut and lower the tire to the ground. 

Not so fast. There’s more to it. In fact, there’s quite a bit more.

To remove the tire/wheel assembly (TWA), the brake assembly must be partially disassembled. This disassembly requires the removal of two or four bolts to release what’s called the brake back plate(s). The TWA can be removed only after the back plate(s) have been removed.

Assuming the airplane has been jacked up far enough to lift the TWA, a large cotter pin must be removed prior to removing the axle nut. Then, the TWA can be pulled from the axle.

There is an inner and an outer bearing. From the earliest parts manuals, Cessna breaks out the parts in wheel assemblies. The bearings are always referred to as cups—often called the “race”—and cones—which are often called the bearings. 

Here’s another thing to know that is hard to find in any manual: Bearings and races are matched pairs. Don’t take the bearing assembly you removed from the race on the valve stem side of the TWA and install it in the race in the non-valve stem side of the TWA.

What grease to use?

Pre-1962 Cessna single-engine service manuals suggested that wheel bearings be cleaned and greased at the first 100 hours time-in-service, and thereafter at 500-hour intervals, unless operated in extremely dusty or sandy conditions. 

The manual specifies MIL-G-25760 grease. However, there’s also a sentence that says that the military specifications are not mandatory, but are listed to serve as a guide. It goes on to say that most products produced by reputable manufacturers meet or exceed these specifications. 

Later Cessna manuals give a different MIL-SPEC number, but cite “general purpose grease.” 

I personally like the 500-hour greasing interval. Unless I’m performing maintenance on an airplane for the first time, that’s the interval I use. 

Cleveland, the manufacturer of brakes and wheels used on Cessna singles, suggests the use of Mobil SHC™ 100 grease. 

Bearing removal, cleaning and greasing

After the TWA has been removed, the bearings are removed. This usually requires the removal of a snap ring, a washer, a felt grease seal and another washer. 

Bearings are then cleaned with Stoddard solvent, applied by either an air-powered solvent sprayer or a brush. Air can be used to blow the grease out, but never spin a bearing by directing compressed air perpendicular to the rollers. 

Directing a stream of air across—not between—the rollers in roller bearings is dangerous because the bearing cage is designed only to maintain the spacing between the rollers. It’s not strong enough to contain the rollers when they rotate at a high rate of speed; in other words, directing air across when bearings can result in fast-moving projectiles.

After the bearing is clean and dry, look for corrosion and/or pitting. If found, replace the bearing and matching race.

Bearings are repacked by putting a gob of clean grease in the palm of either hand and forcing the grease up into the bearing. Press the bearing down into the grease until the bearing comes into contact with your palm. Repeat this procedure until grease appears at the top of the bearing cage.

You can also buy a bearing packer and use it to pack the bearing. Look up “wheel bearing packing tool” on your favorite search engine. YouTube also has wheel bearing packing videos. (See Resources for an additional article that discusses wheel bearing service. —Ed.)

The last step is to look at the grease seals. For decades, Cleveland, the manufacturer of most GA wheels and brakes, has used felt pads to seal against sand and fine dirt. These seals are inexpensive and work well. 

Recently, Cleveland has replaced the felt pads with molded rubber grease seals. These may be used in place of the felt seals.

Putting it all back together

The newly-greased bearings are reinstalled in the side of the wheel which they came from. Slide the TWA onto the axle. If it doesn’t slide all the way on, you’ve got the large steel washers on each side of the felt seal in wrong. Swap the washers around until the TWA slides all the way onto the axle.

Thread the axle nut onto the axle. 

How tight should it be? I couldn’t find definitive information on how tight the axle nut should be. Field experience suggests to tighten the nut up well to seat the bearings, then loosen it until you can feel a slight movement of the wheel in and out on the axle, then snug it back down until the TWA spins without resistance and no in-out movement is felt.

Now, to reassemble the brake. Two or four bolts were removed so the back plate could be removed to free the brake disc from the inner and outer brake pads. 

Whenever I have a TWA off the axle, I clean up the brake guide pins with a Scotchbrite pad. I also clean the guide pin holes in the torque plate. These guide pins must slide in and out to allow the brake to self-adjust as the brake pads wear. 

The devil is in the details

The last step is often missed as it’s not in the Cessna manual. It’s found in the Cleveland Wheels and Brakes Component Maintenance Manual, Appendix A titled, “Wear Limits and Torque Values.” This manual, and all of the Cleveland wheel and brake manuals, are available for free on the Cleveland website. Start by downloading the Technician’s Service Guide. (See link in Resources. —Ed.)


Oftentimes, similar-looking parts call for different torque values. It is crucial to use the correct value for your part.


This critical step in reassembly is applying the proper torque to the two or four back plate tie bolts. Overtorqueing the bolts can deform the brake housing. 

The proper torque on almost every Cessna single engine brake is 75 to 90 inch-pounds (6.25 to 8.5 foot-pounds). That ain’t much. It doesn’t need to be much since these bolts aren’t in a compression application. They are loaded in shear, and as long as these bolts are snugged down to the proper torque, that’s sufficient. 

Sign off your work

The good news is that owners can legally do a lot of work on their airplanes. However, as mentioned, there are catches. Catch No. 1 is that you must own or have access to the manuals. Catch No. 2 is that you must enter the work you performed in the aircraft records in a manner that’s acceptable to the Administrator. That’s FAA talk for the head of the agency. 

The requirements for these entries are listed in FAR 43.9. It says if you perform PM, you shall make an entry in the maintenance records containing the following information:

1. A description of the work performed.

2. The date the work was completed.

3. The name of the person performing the work.

4. If the work was performed satisfactorily, the name certificate, certificate number and signature of the person performing the work. The signature constitutes an approval for return to service only for the work performed. 

(This is a summary of FAR 43.9. Please refer to Resources for a link to the complete text. —Ed.)

Notice that the regulations do not require the entry to include the aircraft total time or tach time, but it’s extremely helpful to include that information. 

An example1 of an entry for the work described above would read:

Month/day/year. “Greased left and right main landing gear wheels in accordance with information in the Cessna (model number) service manual and the Cleveland Wheel and Brake Component Maintenance Manual, Appendix A, paragraph A3.”

Signed: Joe Pilot Cert # 1245654

The point of this article is to make sure owners understand the freedom and the limitations that are part of owner-performed PM. Go ahead and do it, but make sure you do it right; by the book. 

1For more about complete and detailed logbook entries, see “Deciphering Logbooks” by Kristin Winter in the November 2017 issue. 

Know your FAR/AIM and check with your mechanic before starting any work.

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California, with his wife Audrey. Send questions and comments to



Part 43.3, Part 43.9, Part 43.13, Appendix A to Part 43
Electronic Code of Federal Regulations

Technician’s Service Guide AWBTSG0001-1

Cleveland Wheels & Brakes – CFA supporter
Component Maintenance Manual AWBCMM0001-12
Cleveland Wheels & Brakes – CFA supporter
“DIY Wheel Bearing Service” by Jacqueline Shipe
Cessna Flyer, July 2016 
Cessna Flap Tracks Inspection & Replacement

Cessna Flap Tracks Inspection & Replacement


Cessna flap tracks eventually wear out, and when they do, it’s an airworthiness issue. Here’s how STEVE ELLS changed four flap supports, more commonly known as flap tracks, on a Cessna 150.


In 1995, Cessna issued Single Engine Service Bulletin (SEB) 95-3. This 27-page bulletin, titled “Flap Support Inspection and Roller Washer Installation,” applies to most single-engine Cessna airplanes including the Agwagon series, the 206/207 heavy haulers and the 210 high performance retractable airplanes. It does not apply to 172R, S; 182S, T; T182T; 206H; T206H or 208 aircraft. Cessna considers SEB 95-3 Revision 1 a mandatory bulletin. 

The initial inspection in the bulletin wants owners to check the flap tracks for damage such as wear, gouges and cracks; and for security of attachment. It also mandates the installation of special stainless steel washers on the inner and outer side of the forward flap rollers. These washers protect the flap supports from wear. 

If the initial inspection shows that the tracks and rollers are in good shape, all that’s required is the installation of the special washers—Cessna Part No. S1450-3S10-032—which have a $2.99 list price. 

Any gouges can be polished out, providing the metal removed doesn’t exceed 0.020 inches in depth. 

Often, due to improper lubrication, dirt and other contamination between the tracks and rollers, the slots in the flap track eventually become oversized. A track is worn out if either slot in the track is wider than 0.6035 inches. 

McFarlane Aviation makes an easy-to-use gauge (McFarlane Part No. 950; cost $41.21) to determine if the flap track slots are worn beyond the 0.6035-inch limit. The following paragraph from the McFarlane website describes the wear process:

“The flap rollers wear into the flap support arms on Cessna aircraft. This wear is caused by the flap rollers due to the asymmetric extension or retraction of the flap during flight. This asymmetry is caused by the inboard or outboard section of the flap leading the retraction or extension of the flap. Many factors, including rusty or damaged rollers or flap track imperfections, can contribute to this condition. This asymmetry causes the rollers to be pressed against the flap support arms (roller end loading) which, over time, causes damage to the flap support arms and structurally weakens the flap.”

Instead of wearing the metal away, the metal at the edges of the track slots gets displaced. This displacement is often called “mushrooming.”

Assessing the flap tracks and getting the parts

Recently I helped Martin Caskey, the local hard-working A&P mechanic at C Aero Services on the Paso Robles Municipal Airport (KPRB), change all four flap supports—often called flap tracks—on the local soaring club’s 1964 Cessna 150 with a 150 hp engine. 

It took longer than we thought it would.

Our inspection showed mushrooming on all four flap tracks and accelerated wear where the flap rollers bore in the tracks at the 20-degree flap extension spot. The tracks were worn out. 

The trusty 150 had an airframe total time of 5,788.5 hours, and the flap tracks had never been changed. The flaps—manually operated in this 150—could still be deployed and retracted at will, but there were obvious signs of wear.

There’s no doubt that some of the wear was due to the fact the 150 had spent the last few years of its life pulling gliders and sailplanes aloft with the flaps at 20 degrees during high-power tow operations at best rate-of-climb airspeeds. 

Previously Martin had replaced the rollers and the associated bushings and washers by installing McFarlane Aviation’s Flap Roller Upgrade Kit (Part No. FLP-KT-1U). This kit includes the special washers called out in SEB 95-3 R1, and all the parts needed to replace all the existing flap rollers and hardware. The roller kit for our 150 cost $476.74. (McFarlane has also developed roller upgrade kits for other Cessnas that cost between $475 and $715, depending on the airplane. —Ed.)

We needed four new tracks. Again, McFarlane Aviation was the place to go. Not only did its FAA PMA tracks have improvements over the original tracks, they were markedly less expensive. 

We bought four MC0523231-14 flap tracks at a price of $237.15 each, for a total of $948.60. The McFarlane tracks are made of material that is an improvement over the original tracks. According to McFarlane, its tracks are 20 percent stronger which translates to six times the fatigue strength. They’re also a lot less expensive than the Cessna parts which retail for over $600 each. 


Removing a flap track

There’s no easy way to remove a flap track. First, the flaps must be removed; then all the upper and lower rivets that hold the flap cove sheet metal in place must be carefully drilled out. This exposes the bracketry that secures the flap tracks. 

Each flap track for our C-150 is secured by 9 1/8-inch diameter AN470AD-4 rivets. We drilled those out and removed the tracks. On the workbench we aligned the old and new tracks by running a roller back and forth in the slots when the tracks were clamped loosely together. 

Once the roller moved smoothly, the clamps were tightened. Then, using the old tracks as drill guides, holes were drilled in the new tracks.


Installing the new flap tracks

After sliding the new tracks into position in the supports, we installed and bucked new rivets. 

Following the installation, Martin and I riveted the flap cove sheet metal back in place and installed the flaps after we had cleaned and lubricated the needle bearings in each roller with grease. 

There are no specific instructions in many Cessna single engine maintenance manuals about the proper lubrication of flap rollers. The rollers in the McFarlane upgrade kit roll on needle bearings, which should be removed, cleaned and greased periodically. 

Squirting a general lubricant on the outside surface of the roller may cause the roller to slide—instead of roll—in the flap track grooves. Rolling is low friction; sliding is high friction and contributes to accelerated flap track groove wear. 

McFarlane also has a flap roller installation tool (McFarlane Part No. 970; cost $37.32) that makes it easy to align the rollers. It’s very helpful when working through the small access holes in the flap when installing the aft flap rollers.


Changing four flap system pulleys

The flap actuating cables from the manual flap handle are routed aft from the handle to four pulleys located in the belly of the airplane. The cables turn 90 degrees at pulleys; two cables are routed to the left flap and two to the right flap. 

There are two more 90-degree cable turns: one each just inside of the cabin wall where the cables are turned to run up to the wing root, and one in the wing root where the cables are rerouted to run out the inside of the wing to the left and right flap bell cranks. 

In our 150 project, the flap cable tension rigging was complicated by four worn pulleys. Martin and I decided to change the pulleys (Cessna Part No. S378-2) in the belly due to wear in the pulley grooves. 

At the end of the job, the tracks were stronger; the needle bearings in the rollers were properly lubricated; the pulleys in the system were pivoting on their bearings; and the flap cable tensions were correct. We felt that the flap system was now in better-than-new shape.

The parts costs totaled $1,654. Labor man-hours added up to 48. That may seem like a lot of money to spend on a flap system that seemed to be working, but according to the manufacturer, the tracks were worn out. To maintain airworthiness, they needed to be changed. The entire flap system in this hard-working 150 is again airworthy. 

Know your FAR/AIM and check with your mechanic before starting any work.

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California, with his wife Audrey. Send questions and comments to  


McFarlane Aviation Products
– CFA supporter


C Aero Services



Single Engine Bulletin
(SEB) 95-03 Revision 1

“Flap Support Inspection and
Roller Washer Installation” under “Magazine Extras”

Engine Mounts Explained

Engine Mounts Explained

The engine mount represents a crucial link between your engine and airframe, and should be treated as a mission-critical accessory. STEVE ELLS visited Loree Air, an FAA-certified repair station, for insight into the engine mount repair process.


I've found no evidence that my engine mount—that web of steel tubes that supports the engine and nosegear on my 1960 airframe—had ever been overhauled or recertified.

It seems a bit hard to believe. After all, it’s been bolted onto my airplane for 57 years. You’d think one mechanic or owner along the way would question whether the mount had suffered the ravages of time or had any issues. But like I said, when I started digging in the logs, I found no maintenance record entry that showed it had ever received specific attention.

I recently discovered a cracked tube, and when I scrubbed it with a wire brush, I found a gaping hole—the tube had rusted through from the inside. I removed the welded steel mount in order to send it in for repair and recertification. 

As it turned out, the tube with the rusted spot was only one of seven tubes that had to be replaced. I had no idea the mount was in such bad shape!

Dents are repaired during the Loree Air rework. According to Steve Loree, the circular slot around the bolt hole is how moisture—a cornerstone of the rust process—enters the tubing in the mount. Loree seals this slot during rework.
What engine mounts are made of

SAE grade 4130 steel, also known as chrome-moly, is a through-hardened chromium-molybdenum steel alloy that is used in the light airplane industry where light, strong tubing is needed. It’s strong for its weight, easy to work, easy to weld and provides a good cost-to-strength ratio. 

Chrome-moly steel is available from aviation parts suppliers such as CFA supporters Acorn Welding, Aircraft Spruce and Airparts Inc. Wicks Aircraft also supplies this tubing. (Another CFA supporter, Wilco, Inc., carries SAE 4130 in sheets. —Ed.)

The seven tubes that were replaced on my engine mount consisted of one 1/2-inch diameter tube, two 5/8-inch diameter tubes and four 3/4-inch diameter tubes. 

Chrome-moly tubing is purchased by specifying the outside diameter (OD) in 1/16-inch steps, and the wall thickness. The wall thickness of the 5/8-inch OD tubes in my engine mount is 0.035 inch. 0.035 inch is close to the thickness of a credit card. The wall thickness of the 1/2-inch OD tubes is 0.049 inch. 0.049 inch is approximately the thickness of a CD. 

The 1/2-inch and 5/8-inch tubes sell for $4.35 per foot at Aircraft Spruce; the 3/4-inch tube is $3.35 per foot. 

I needed 4 feet of 5/8-inch tube and 68 inches of 3/4-inch tube to repair my mount, before it could be recertified as airworthy. The materials cost was less than $50 at retail prices. 

A chrome-moly steel mount is a sweet piece of engineering. My refurbished engine mount (as delivered to me) weighs 15 pounds, 11 ounces; yet it is strong enough to support the aircraft’s Lycoming O-360 engine (258 pounds), a Hartzell two-bladed propeller (51 pounds) and support and endure the shocks suffered by my retractable nosegear. 

Rust was clearly present in all of the seven tubes replaced by Loree Air.
Removing and sending the mount out for repairs

After I found the hole in the lower right tube, I removed the engine and nose landing gear assembly. Removing parts, like the demolition phase of a room remodel, always goes quickly. In this case, I knew I needed to label and sort the parts and engine accessories because it was going to be almost two months before I was going to be reinstalling the engine and nosegear. 

One trick I’ve used for years when removing an engine or other assembly is to take photos of everything before picking up the wrenches. When I first heard of this photo trick, shops were using Polaroid cameras. Today, a cell phone and/or tablet is more than sufficient. 

One of the decisions that I pored over was where to send the mount for repair and recertification. I wanted an FAA-certified repair station that had the capabilities to repair and recertify my mount. My favorite internet search engine turned up four options. They were, in alphabetical order: Acorn Welding Ltd., Aero Fabricators (a division of Wag-Aero), Aerospace Welding Minneapolis and Loree Air, Inc. and I have no doubt that there are others. 

I also searched for a used, serviceable mount. I found one on the East Coast and negotiated what I thought was a good price—but after learning that it would take more than $500 to ship it to me on the West Coast, the deal fell through.

Obviously, the cost of shipping a mount, as well as how to ship a mount, must be considered. Companies told me that the most common method is to bolt the mount to a piece of stout plywood, then either build a wooden or cardboard box around it for shipping by UPS or FedEx; or to bolt the mount to a pallet and ship it as truck freight. Since the repair facility has no control over handling after it leaves their possession, it’s critical to create a shipping container that protects the mount during shipping. 

CFA supporter Aero Fabricators quoted me $1,400, which included changing up to 10 tubes, and told me the turnaround time was two to three weeks. Aerospace Welding quoted a price of more than $2,500. 

Another CFA supporter, Acorn Welding, was unable to estimate their cost over the phone, but Paul Gyrko, head of sales, took the time to answer my questions and explain the full process when I called for information. (Acorn Welding also sells new engine mounts for certain Cessna 180/185 and 182 models. —Ed.)

Steve Loree, Jr. at Loree Air told me that the cost to inspect, repair, normalize, paint and certify my mount would be $1,700, with any additional work costing more, up to a maximum of $2,100. Loree also warned me the company had a five-week backlog. 

Given that Loree Air was only 278 road miles away from my home base—while the other three were all over 1,800 road miles away—and that I had good reports from friends that had used them, I decided to use the five-week window for other tasks and took my mount to Loree.

After a friend offered to fly me up to Placerville to drop off the mount, I packed my sad old mount in the back of my buddy’s aircraft and flew it up to the Placerville, California airport (KPVF) where I left it with Nicole, who runs the office. 

Ready for pickup

Steve Jr. called on a Tuesday in late June to tell me that, after cleaning and sandblasting all the paint off my mount, a thorough inspection revealed some surface damage to the exterior of a couple of tubes; bends in two tubes; and more tubes that showed evidence of internal rust. 

I asked him if it was OK if I drove to the shop once my mount was finished; I wanted to hang around and ask a lot of questions about mount damage and repairs. I figured this was an opportunity to pick up some hints and tips that a mechanic in the field could use to determine if a welded steel tube engine mount or landing gear support structure was airworthy. He said that would be fine.

Five weeks later I got the call; the repaired mount was ready. 

I arrived at Loree Air at 10:30 Monday morning. I met the entire staff: Steve Sr., Steve Jr. and Nicole (who is married to Steve Jr.). I was also sniffed up and down by Layla, the small four-legged office assistant and guard dog.

Steve Sr. attained his welding certification at the San Diego shipyards and went to Sacramento City College for his A&P education at the suggestion of his flight instructor. He gained a wide range of reciprocating engine skills at the Sacramento Sky Ranch before spending 15 years working at the Sacramento Citation Center and at Aircraft Conversion Technology in Lincoln, California, with owner Bill Piper. 

Seeing the need for a certified aircraft welding shop in California and wishing to steer his own path, Steve Sr. opened Loree Air in 1992 in a small shop in the Swansboro Country neighborhood in the foothills east of Sacramento, near Placerville.

In 2011, Steve Jr. joined his father in the business. They decided that since the shop needed to grow in order to support two families, it was time to expand. To do so, Steve Jr. said, “I think we need a website,” but Steve Sr. wondered if it was necessary. Word-of-mouth advertising had been effective and the company had all the work it could handle. But Steve Sr. yielded, and today you can visit Loree Air online at 

After consistent growth—thanks to the website—the Steves decided to move the company to a small warehouse and shop in Diamond Springs, another community near Placerville. 

With the help of many friends and family members, they planned and built a shop to fit the company’s needs. 

There had to be a large sandblast booth to clean mounts. There had to be a paint booth. There had to be an area for grinding and smoothing metal. The shop needed an area where mounts were put into jigs for alignment and buildup. A screened area was required for welding. A separate office and customer reception area were part of the plan as well.

There are also two lofts for storing parts and ready-to-ship mounts and nose strut welded tube support structures. 

While I had opted to take my mount to Loree Air for repair, the company does stock repaired and certified mounts for some popular aircraft. 

Problem areas

The Steves spent some time describing why my engine mount rusted out and passed on tips for determining if a welded steel engine mount is airworthy.

Loree told me that the most common problem they see on Cessna welded steel mounts is corrosion on Cessna 180 and 182 mounts due to the proximity to the left and right exhaust manifolds. Loree has developed a FAA-approved heat shield designed to prevent extreme exhaust heat from affecting the forward section of the main support tubes and the diagonal tubes. 

I was also told that it’s common to see cracking in the 172 engine mount’s cross tube. 

Inspection tips and tricks

I asked the Steves for tips to help field mechanics determine if the welded steel mounts they inspect are airworthy. They said one test is to use an automatic center punch to put a small dent in the end of a tube that is believed to be unaffected by internal corrosion and compare that to the dent when the punch is used on the part of the tube that is suspected to be corroded. Usually this means comparing the dent at the highest part of the tube near a weld cluster to a dent in the lowest part of the tube. 

Any difference in the depths of the two dents is clear evidence the lower end of the tube has been weakened by internal corrosion.

While at the Loree shop, I also saw tubes that were dented during installation and removal by sloppy tool handling; and tubes that had been scratched or scored by abrasion.

Since these tubes are so thin, what may at first appear to be negligible damage usually needs attention. “Our standard for repair is 10 percent of the tube thickness,” said Loree.

One thing Loree was adamant about is avoiding the use of plastic tie-wraps (i.e., zip ties) to secure anything to a welded steel mount. He has seen it again and again: plastic tie-wraps will wear a welded steel mount tube faster than a pilot heads to a restroom after a cross-country flight. It takes longer to install properly-sized Adel clamps, but they are the only clamping device Loree wants used on an engine mount. 

You and your mount

I was surprised to hear Steve Sr. say that in all his years repairing mounts he had seen very few engine mounts pass through his shop that needed no repairs. 

I was also surprised when my mount needed seven tubes replaced. 

Then I saw pictures of the inside of those tubes. They were all rusted to one degree or another. I believe good fortune was smiling on me when I found the crack that lead me to remove my mount to send it for repair. 

Based on what I learned and saw, I recommend that owners send their engine mounts to a certified mount repair shop to get inspected, repaired-as-necessary and recertified whenever their engine is removed for overhaul.

Left to Right, Top to Bottom: Steve Sr.; Steve Jr.; Nicole; Layla (the hairy one).

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California, with his wife Audrey. Send questions and comments to . 


Acorn Welding

Aircraft Spruce and Specialty Co. 

Airparts Inc. 


Wicks Aircraft and Motorsports 


Wilco, Inc.


Acorn Welding Ltd.

Aero Fabricators
(a division of Wag-Aero)

Aerospace Welding Minneapolis

Loree Air, Inc.

– CFA supporter

Acorn Welding Ltd. 

ITW Pro Brands

Is Your Engine Worn Out? How to Tell & What to Do About It

Is Your Engine Worn Out? How to Tell & What to Do About It


Smart owners who monitor key performance indicators can tell if an engine is still good or whether “it’s time.” If your engine is due for an overhaul or replacement, STEVE ELLS has a list of options which can save you time, money and maybe even both.


The day before the start of what I’m now calling the best EAA AirVenture Oshkosh ever (See page 60 for Steve’s AirVenture report. —Ed.), I stood before an enthusiastic group of Cessna Flyer Association members at the annual Gathering at Waupaca, Wisconsin. It was 7:30 a.m. Sunday morning. I made sure everyone was awake by asking a scary question.

I asked how many owners thought they had an engine overhaul looming on the horizon. Seven hands went up. Those owners reflected the concerns of many owners. Engine overhauls are expensive; not to mention they can be time-consuming and stressful.

It is difficult for owners who don’t deal with overhauls on a daily or weekly basis to be able to tell when “it’s time.” An engine can be worn out, but it will still start, develop power and appear to be operating normally. On the other side of the coin, it’s also certainly possible for an engine to be running well and in good condition far beyond the manufacturer’s recommended time between overhaul (TBO).

I’m going to provide a few guidelines for determining your engine’s health.

The engine’s bottom end (and why it matters)

The air-cooled direct-drive engines we fly behind are stout; especially the “bottom end” portions. The bottom end includes the case, crankshaft, connecting rods, camshaft, lifters and accessory gears and accessory housing.

Just because the compression is low in one, two or all cylinders does not mean the engine is ready for an overhaul. Cylinders can be removed and rebuilt, or replaced with new cylinders without disturbing or compromising the bottom end. But when an engine’s bottom end is worn out, nothing short of an overhaul will restore it to airworthy condition. 

Oil pressure

Idling oil pressure when the engine is hot is an excellent indicator of the health of the bottom end of an engine. The hot idling oil pressure of our engines should always stay above the lower red line on the oil pressure gauge. 

The oil pressure limits and acceptable range are in every owner’s manual and pilot operating handbook (POH). As a rule, Lycoming engines have a 25 psi low oil pressure limit and Continental engines have a 10 psi low oil pressure limit. 

One of the most important factors in maintaining oil pressure is the clearance between the crankshaft journals and main crankshaft bearings. The spinning crankshaft in an engine is supported by a cushion of lubricating oil under pressure. 

Since there is a gap between the outside diameter of the journals of the crankshaft and the inside diameter of the main bearings surrounding each journal, the oil that’s pumped in also flows out through the gap between the two. The size of the gap is a major determinant of idling oil pressure. When the gap grows due to wear, the leakage through the gap increases and idling oil pressure goes down. Low idling oil pressure almost always signals that the bottom end of your engine is worn out, or that there’s another problem with the bottom end.

Oil consumption limits

It’s rare for an air-cooled Avgas-burning engine to not use any oil. Manufacturers are tasked with producing engines that must perform in conditions ranging from below zero F outside air temperature (OAT) to 100 F plus OAT. The engines must produce rated power in missions where the aircraft may take off from extremely hot temperatures on the ground, only to climb rapidly to altitude where OATs are below freezing. Given all the metallurgical expansions and contractions that take place due to these extremes, air-cooled aircraft engines are intentionally built to larger tolerances than any automobile engine.

Oil usage is one of the trade-offs that result from building air-cooled engines that perform as well as ours do. 

If your aircraft’s engine uses oil, that’s normal. But how much is too much? Luckily, there’s a formula for that. Lycoming’s Service Instruction 1427C, “Lycoming Reciprocating Engine Break-In and Oil Consumption,” provides the following formula: 

0.006 x BHP x 4 ÷ 7.4 = quarts per hour.

Let’s find the allowable oil consumption for a 180 hp engine. BHP is an acronym for brake horsepower, so the formula works out like this. First, multiply: 0.006 x 180 x 4 = 3.6. Dividing that by 7.4 yields a maximum oil consumption for a 180 hp engine of 0.58 quarts per hour, or a quart every 1.7 hours. 

The same formula applied to a 300 hp engine yields a maximum oil usage
of 0.97 quarts per hour. 

The only drawback with very high oil consumption is that it limits flight leg length. If your engine has a 4-quart sump, you’re not going very far if your engine is going through 2 quarts an hour.

Many owners are unaware that each engine and airframe combination has an oil level “sweet spot,” where consumption slows. 

Above this level, much of the oil is discharged out the crankcase breather tube. The oil is not being consumed; it’s simply being pumped out the breather tube. If you see a lot of oil on the belly of your airplane aft of the breather tube, you are probably over-oiling your engine.

The sweet spot in the 1966 Cessna 182J Skylane with a Continental O-470-R I used to own was 9 quarts, even though the oil capacity was 12 quarts. The consumption rate for my current Lycoming O-360 is 1 quart every five hours. My average cross-country leg is around four hours so I just carry some oil and add about a quart at every stop. 

The key is to first fill to the sweet spot for your airframe/engine and then use consumption from that level to determine your engine’s oil consumption. 

Oil leaks

Damaged engine cases can cause persistent, hard-to-find oil leaks. Cases can and do crack, leading to loss of oil. 

Lycoming narrow-deck engines—the standard configuration before the mid-1960s—can develop a difficult-to-find leak when the engine case through bolts are loosened and then retightened during a cylinder change or top overhaul. The sealing O-rings between the case halves often fail to reseal the through studs after the cylinder(s) are reinstalled and torqued down. The result is a persistent oil leak past one or more of the through studs. 

There’s no way to stop that leak, nor is there a way to fix a leaky crankcase crack short of engine disassembly. 

Section 6-4.12 of Continental Motors Publication M-0, “Standard Practice Maintenance Manual for Spark Ignited Engines,” covers crankcase inspections and allowable cracks. There is a provision for continued operation of certain engines with limited cracks in noncritical areas of the crankcase. However, the engine will continue to leak oil through the crack. 

I once found a leak in my engine by thoroughly cleaning the outside of the engine, then adding a small amount of fluorescent dye to the oil. I bought the dye and a black light at the local auto parts store. I waited for a dark night, then after a ground run, found the leak by shining a black light on the engine. I rebuilt the engine soon afterward. (Be aware of all regulations and the potential hazards before introducing a foreign substance into an aircraft’s engine or oil. —Ed.)

Oil screen and oil filter inspections

Always cut open the spin-on oil filter and inspect the filter media for contamination. I cut the paper media at the edges so I can unfold it for visual inspection. 

Engines that don’t have a spin-on filter will have a pressure screen. Remove it at every oil change and flush it.

If the filter media or screen reveals a quantity of metal that exceeds a quarter teaspoon, Lycoming mandates grounding the airplane until the cause can be found. Lycoming Service Bulletin 480F describes proper procedures for oil filter or screen inspections as well as corrective actions if the inspection shows contamination. 

Jacqueline Shipe’s article “I Found This in my Oil” (May 2017 issue of Cessna Flyer) provides a pictorial guide to oil filter inspection. —Ed.


Black oil

If the engine oil turns black in the first 10 hours after an oil change, yet the compression readings are good, combustion gas byproducts are blowing past the pistons and piston rings into the bottom end of the engine. The oil will continue to lubricate, protect and cool the engine, but due to the contamination from combustion byproducts, it’s a good idea to shorten the oil change interval. 

Compression tests and borescope valve inspections

Never pull a cylinder based on one compression reading. Compression test results can vary from flight to flight. Always fly the airplane to bring temperatures up into normal operating range. If you have a low reading, go fly a bit, and then perform a second, and possibly a third compression test. 

Lycoming’s guidelines specify that each cylinder’s compression reading should be above 70/80, and within 5 psi of the engine’s other cylinders. When compression readings fall below 70/80, Lycoming says that’s the result of wear and should be further evaluated. 

There are very detailed instructions in Continental Publication M-0, Chapter 6-4.11.1 through 11.3 describing procedures and guidelines for compression tests. For instance, tests are only valid if a calibrated compression testing tool is used. The calibration procedure provides a low limit compression reading number for that specific testing tool.

Any cylinder with a compression reading above that limit is airworthy, provided a borescope internal inspection of the cylinder does not show cylinder wall scoring or extreme wear and the exhaust valve does not show any signs of burning. 

Many A&P technicians are not aware of the proper compression testing procedure for Continental engines. If your mechanic calls saying your compressions are too low, make sure he reads and understands the Continental procedures which are spelled out in detail in Chapter 6-4.11.2 of Continental Motors Publication M-0.

I strongly recommend that all airplane owners download this manual (it’s free) from the Continental website. There’s
a wealth of general information that, in my opinion, is useful to all air-cooled
airplane engine operators.

Now what?

Let’s assume that you’ve gotten some bad news from these tests. You’re facing an engine overhaul or replacement. What are your options?

There’s a choice of factory new, factory overhauled, factory rebuilt, repair station overhauled or field overhauled engines.

This is also an excellent time to research the STC data on the FAA website to find out if there are any engine upgrades such as installing a more powerful engine in place of the original engine. Some airframes may be eligible for engine upgrades via STC. An upgraded engine may be able to give you better performance and/or reliability. 

Finally, you may want to consider replacing your worn-out engine with a lower-time used engine. 

Cessna OEM engines

Obviously, buying a new “zero-time” engine from Lycoming or Continental will be the most expensive option. A factory rebuilt zero-time (exchange) engine is usually the next most expensive, followed by a factory “time since major” overhaul where the manufacturer overhauls your current engine. 

There are some very good reasons to deal directly with Lycoming and Continental. First, the price quoted is fixed, meaning there won’t be any unexpected price “modification” phone calls. 

Second, it’s broadly accepted that a factory zero-time engine will add value to any airplane. Remember that there are two flavors of factory zero-time engines. A brand-new factory engine is built from all new parts. A rebuilt engine is built with a combination of new parts and used parts which meet new limits. Both come with fresh, zero-time logbooks.

Third, and maybe the most important, is that you can continue to fly your airplane until the day your new engine is drop-shipped to your hangar or the nearest maintenance shop.

It’s a great advantage to have the removed engine and the new engine side-by-side during an engine change. This ensures that all the fittings are available and that routing questions can be answered without having to rely on memory or digital photos taken prior to engine removal. 

All Continental and Lycoming factory engines are sold with a core charge. The core charge for a Lycoming O-360-A1A engine is currently $16,400. If a buyer wants to keep the engine that’s been removed, or can sell it for a better price than the core charge, he/she is free to do that. However, the core charge must be paid if an engine is not returned to the factory.

The window to return the removed core engine is usually 90 days. 

Recent offerings

A relatively new option in new engines is Superior Air Parts’ Type Certificated fuel-injected 180 hp Vantage engine. It is approved for Cessna 172R and 172S models via an STC. 

Several companies have obtained or are in the process of obtaining approvals for installation of diesel engines in some Cessna models. 


Repair station or field overhaul

There are excellent non-manufacturer overhauls and not-so-good non-manufacturer overhauls. The excellent ones are built to new limits. The not-so-good are built to what’s called service limits. It’s legal for a shop to build an engine to the worn end of the manufacturer’s service limits guidelines. Of course, the engine won’t last as long as a “new limits” overhaul. When you’re gathering quotes from overhaul shops, make sure that you specify that you want your engine overhauled to new limits. 

Choosing a factory overhaul means your airplane will be down while your engine is removed, boxed for shipping, overhauled and shipped back. During a repair station overhaul or field overhaul of your engine your airplane will be down while the engine is disassembled, the parts inspected and certified, and the engine is reassembled and tested. Smaller repair stations and field overhaul shops typically must box and ship the ferrous parts and the engine case to a specialty shop for inspection and certification. 

There are 77 Type 1 (less than 400 hp) engine repair stations listed in the FAA’s repair station directory. Repair stations have submitted organizational plans and plans for parts accountability and quality assurance to the FAA.

What is included in an overhaul?

Factory engines typically come with a carburetor or fuel injection system, two magnetos and ignition harness, spark plugs, starter, oil cooler and engine-driven fuel pump. This is also the case with most non-factory overhaul options, but you’ll want to double-check to make sure these items are included.

It’s important to take notice of and budget for what’s not included. Time and money must be devoted to inspecting, purchasing, repairing and in some cases overhauling the turbocharger and wastegate (if installed), the exhaust system, the engine mount, the cooling baffles, the generator or alternator, hoses, engine mount and vibration isolators, propeller, prop governor, vacuum pump and fuel boost pump. 

Though you don’t necessarily have to replace or rebuild all of these items at the same time as the engine overhaul, it’s certainly more cost-effective to address them when the engine is already off the airplane. Access is easier, and you can minimize installation and removal hours. 

Most of the larger overhaul shops have worked out favorable pricing with over-the-road shipping companies but shipping costs must also be included during overhaul budget planning. 

It’s also critical to compare the warranties offered by each vendor as there is no industry standard for coverage. 

Can I overhaul my engine myself?

The FAA considers the overhaul of all except a very few engines to be minor repairs, not major repairs. This assumes that the person doing the work adheres to the procedures in the manufacturer’s engine overhaul and inspection manuals. 

You as the aircraft owner (or anyone else) may overhaul your engines, as long as a certificated A&P mechanic oversees the work and he/she is willing to sign off the overhaul. 

If you or your mechanic aren’t ready to do it yourself, there’s no reason a local machinist with years of engine building experience can’t build your engine. Again, this assumes the factory overhaul procedures are adhered to and an A&P is willing to supervise and sign off.

There are some caveats to this approach. 

• Your A&P must agree to this option, and must oversee it to the extent that he/she will sign it off.

• You (or the builder) must use aircraft quality parts.

• You (or the builder) must comply with applicable engine manufacturer Service Bulletins.

• You (or the builder) must comply with all applicable Airworthiness Directives (ADs).

• You (or the builder) must follow the machining processes outlined by the engine manufacturer. 

• You (or the builder) must follow the engine manufacturer’s break-in procedures.

If you’re not sure about the details involved in a light aircraft engine overhaul, there’s a 36-minute video on rebuilding a Lycoming engine on YouTube. (See Resources for the link.
—Ed.) Once you watch the video, it’s easy to see that these engines aren’t complex, nor are they difficult to overhaul. 

Aircraft owners have another option to enhance their knowledge prior to attempting an overhaul. Lycoming offers engine teardown and assembly classes throughout the year in Pennsylvania.

Used guaranteed engines

Another option to get your aircraft back in the air is to buy a used, serviceable engine from an aircraft salvage yard. This is not as radical an option as it may sound. All reputable salvage yards guarantee (warranty) their engines.

Ideally, you’re looking for a first run or first overhaul engine which is mid-time or less. For instance, as of the writing of this article, Wentworth Aircraft had an O-360-A3A with 217 hours since major overhaul for sale for $15,500. Though this engine wouldn’t do me any good (I have an -A1A, not an -A3A, and the two aren’t interchangeable), it does illustrate that there are cost-effective used engines available. The used route is dependent on finding the correct engine. 

An advantage of installing a used engine is the lack of core charge. The $15,500 cost mentioned above could be reduced by a few thousand dollars if you’re able to find a buyer for your core. Your worn-out engine may be just what another owner or kitplane builder is looking for.

Another source for used serviceable engines are engine upgrade specialists. Check the Cessna Yellow Pages online or call CFA for more information about Cessna Flyer supporters. 

You can also often find good engines on the buy-and-sell pages of various online forums, via the For Sale/Wanted thread on the forums, or through the advertisers in this magazine. 



Not every engine showing trouble signs needs an immediate overhaul. However, if you and your mechanic have determined an overhaul or replacement is needed, there are several options. Take your time, do your research and you’ll be back up in the air soon. 

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California with his wife Audrey. Send questions and comments to

Further reading and research
Lycoming Service Instruction 1427C,
Lycoming Service Bulletin 480F, and
Contintental Motors’ publication M-0 under “Magazine Extras”

FAA STC data

FAA Repair Station directory

Factory engines/rebuilds/factory overhauls – CFA supporters
Continental Motors Group

Lycoming Engines

Superior Air Parts

FAA Repair Stations – CFA supporters
Airmark Overhaul, Inc.

Granite Air Center

Poplar Grove Airmotive

Other rebuild and overhaul resource – CFA supporter

Progressive Air Services

Salvage yards – CFA supporters
Dodson International Parts, Inc.

Preferred Airparts, LLC

Wentworth Aircraft

Engine rebuild video

SkywardTech Inc.

Creating a “Mountain Goat” 182, Step One: Off-airport Landing Gear

Creating a “Mountain Goat” 182, Step One: Off-airport Landing Gear

With a successful top-end inspection completed, STEVE ELLS guides a new owner through the first steps to make his Cessna 182 a reliable backcountry plane.

Bill hangars his 1966 Cessna 182J Skylane in the hangar next to mine at the Paso Robles Municipal Airport (KPRB).

Bill is tall, drives a pickup, is comfortably retired—and enjoys flying. He has owned his 182 for four years. It has carried him on cross-country flights to Kansas, Phoenix and San Diego. Since I’ve known him, it seems most of his flights consist of short day-VFR trips to take his wife for lunch.

Last September I saw that Bill’s hangar was open, so I stepped over to catch up. Bill told me that Greg, who was there with him, wanted to buy his airplane. 

Bill hadn’t mentioned wanting to sell. Interested, I listened. 

Bill introduced me as a guy that knew a lot about Cessna 182s. Greg wanted my opinion on the engine in Bill’s airplane, since Bill had told him it had 1,720 hours since its last rebuild. In other words, it was 20 hours past what the manufacturer, Continental Motors, printed as the recommended TBO. 

Bill told him that the engine was running fine; it always started right up, made good power, the oil analyses were always clean and that it had been well taken care of. Bill asked me to inspect the engine to determine if it was airworthy. I agreed to take on that task since the protocol is well defined.

Continental cylinder inspection

In 2016, Continental Motors released Publication M-0, “Maintenance Manual: Standard Practice for Spark Ignition Engines.” This manual is the go-to source for guidance when performing inspections, maintenance and diagnosis on Continental piston aircraft engines. (Make sure you have the most current revision. At press time, the latest iteration is dated July 2017. —Ed.)

Chapter 6-4.11 is titled “Cylinder Inspections.” Sub-chapters include visual inspections, differential compression tests, cylinder borescope inspections, cylinder-to-crankcase mounting inspections, baffle inspections and cowling inspections.

I use both a differential compression test with calibrated orifice and a borescope to determine cylinder health as mandated by M-0. Since the guidelines in the M-0 differential compression chapter differ greatly from the guidelines in FAA Advisory Circular AC 43.13-1B, titled “Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair,” these tools are essential when conducting the Continental cylinder testing. 

I own an Eastern Technology E2M differential compression tester. Aircraft Tool Supply also sells a house-branded differential pressure tester, which they call the 2EM.

I used a VA-400 rigid USB borescope from Oasis Scientific to inspect the valves in accordance with the M-0 protocol. This borescope connects to my laptop which allows me to create a file for storing photographs of everything I see during the inspection.

I performed the inspections of the cylinders in accordance with the chapter and found the compression readings acceptable at 72, 70, 72, 70, 68 and 72/80. A thorough “scoping” inside each cylinder showed no scoring on the cylinder walls, normal lead deposits on the piston crowns and no indication of any valve problems. 

In addition to the cylinder inspection chapter, M-0 also provides guidelines for determining if there are excessive combustion gases escaping past the rings. The test procedures are in Chapter 8-9.1. Bill’s engine also passed this test.

Based on these tests, I concluded that the top end of the 230 hp O-470-R engine in Bill’s airplane was airworthy. Within a week, Greg and Bill had agreed on a price and the airplane (and the hangar) changed hands. 

Greg’s goal

Greg owns a contracting business on the central coast of California. His business is thriving, and he works hard. When he can get away, he enjoys spending time at his cabin high up in the Monache Meadows Wildlife Area in the Sierra Nevada. 

He told me he yearned to get his family, including his 92-year-old mother, up to the cabin often but hasn’t been able to because of the nearly seven-hour drive to get there. Greg figures a flight in his 182 will take no more than 90 minutes. There’s just one catch: the only landing strip is a gravel/sand runway on the edge of a dry lake at 8,000 feet msl. 

I asked Greg why he bought Bill’s 182. Here’s what he said: “Lots of things. The two doors allow me to have my 92-year-old mother go along—it would be too difficult to hop over her in a Piper Warrior/Cherokee.”

“The 182 has horsepower to deal with high altitude better,” he continued. “The 182 is wider and carries a larger payload; my family are all tall and large people.”

“The high wings allow me to clear tall brush on the side of runways: Lone Pine (O26, located 40 miles south of Bishop) was scary with the Warrior I used to own.”

Greg put in a great deal of thought and flight time preparing to fly in to O26 this summer after the snow melts. Within a few weeks after the sale, he had flown to the east side of the Sierra and hired Geoff Pope, a CFI based at the Bishop, California airport (KBIH) for mountain flying instruction. He also took his 182 to the Big Bear City Airport (L35) to learn how it handles doing touch-and-goes at 6,732 feet msl. 

Big tires

During our initial conversations, I suggested that Greg set aside some cash to install a bigger nose tire since his 1966 182 didn’t come from the factory with the left and right firewall reinforcing channels. 

These channels, which reduce the odds of bending the firewall, can be retrofitted to all 1962 through 1970 aircraft by incorporating Cessna service kit SK182-44C in accordance with single engine service letter SE71-5. The kit had not been installed on Greg’s airplane. Cessna installed the channels at the factory beginning in early 1970 with Serial No. 182 60291. (For more information on firewall reinforcement, see Steve’s Q&A column in the January 2018 issue of Cessna Flyer. —Ed.)

I told Greg that his 182J was a good airplane and that it could safely operate out of the strip by his cabin if he factored in variables such as winds aloft, density altitude, weight and balance and was prudent about risk management. 

We decided that the most immediate step in converting his 182 for safely flying into high-altitude unimproved strips like the one near his cabin was to install bigger tires. 


Nose fork upgrade

The standard sized nose tire for 182s like Greg’s is a 5.00-5 tire with a 6-ply rating. During my search for bigger tire solutions, I found that the Cessna parts manual does show the parts for what’s called a Heavy-Duty Nose Gear installation for a 6.00-6 tire, but it requires a different hub and nosegear barrel assembly. 

During Greg’s research, an acquaintance suggested that a Cessna 310 nosegear strut and fork would work. 

Due to the time and expense of searching out parts and approval for the installation of surplus or salvage parts, we decided to seek the advice of Jim Hammer at Airglas Engineering in Anchorage, Alaska. 

Airglas sells an STC-approved large nosegear fork that can be installed on all existing nose landing gear barrels. Large nose forks are available for Cessna singles from the 150 through the 207 and for Piper singles including PA-28-140 through -235, and PA-32-260 and -300. The kit includes the large fork, a new axle and a new strut block. 

The Airglas website contains drop-down menus for each approved model. Topics include pictorial installation instructions, EASA approval docs, STC docs and detailed step-by-step installation instructions.

Greg and I liked what we heard from Airglas and placed an order with Hitchcock Aviation in Star, Idaho. They assembled all the needed hardware, STCs and installation instructions before shipping the package to Greg. 

Jesse Bennett, a local A&P, removed the front strut assembly and disassembled it. A machinist cut the strut tube in accordance with the Airglas instructions and installed the mounting block on the strut. Next, the fork was bolted on and an 8.00-6 6-ply tire and new tube were mounted on a new Cleveland 40-75D wheel assembly. The nosegear strut was reassembled and serviced.

That took care of increasing the footprint of the nose tire. What about the mains?


Working on the mains

The nosewheel assembly, two new heavy-duty double-puck black anodized brake assemblies (Alaskan Bushwheel Part No. 30-52N) and the installation and Instructions for Continued Airworthiness (ICA) manual were purchased from AirFrames Alaska. Installation approval for the wheels and brakes is by Supplemental Type Certificate (STC) SA02231AK held by F. Atlee Dodge in Anchorage, Alaska. 

Greg bought 8.50-6 tires and new tubes for the main landing gear. Parts and approval costs totaled just under $6,000. The strut modification, the installation of the new larger brakes, the block and fork, and the new tires and tubes all happened over the course of one day with hours to spare. 

The new landing gear parts add about 25 pounds to Greg’s aircraft empty weight. The bigger tires and beefier gear also increase drag—so he won’t see the normal 135-knot cruise speeds. But he will be spending more weekends with his family in the mountains; not a bad exchange.

The larger tires provide around 4 more inches of ground clearance and a larger tire footprint. The increased “float” of the larger nose tire drastically reduces the odds of nosegear (and firewall) damage due to uneven runway surfaces. 

After May, when all the snow has melted and the “runway” has dried out, I expect to see Greg gently settling his mother into the copilot seat of his “mountain goat” 182. Next stop: a cabin high up in the Sierras. 

Greg bought an airplane that fit his mission’s needs—and then modified it to increase utility and safety. As a result, he can continue to devote the time needed to care for his contracting customers and spend more “cabin” time with his family. Isn’t that what airplanes are for?


Know your FAR/AIM and check with your mechanic before starting any work.

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California, with his wife Audrey. Send questions and comments to



Aircraft Tool Supply Company
Eastern Technology Corp.
Oasis Scientific, Inc.
Airglas Engineering 
Hitchcock Aviation, LLC
AirFrames Alaska
STC SA02231AK 
F. Atlee Dodge


Publication M-0, “Maintenance Manual: Standard Practice for Spark Ignition Engines”
Continental Motors Group


FAA Advisory Circular AC 43.13-1B
“Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair”
Cessna Single Engine Service Letter SE 71-5 under “Magazine Extras”
Cessna’s In-between Single – The R172K Hawk XP

Cessna’s In-between Single – The R172K Hawk XP

The final result of a three-decades-long quest to fill the gap between the 172 and 182, Cessna’s R172K Hawk XP is a stellar performer in a 172-sized package.

When it’s boiled down to basics, the Cessna Hawk XP (XP for Extra Performance) is a four-place Cessna 172 Skyhawk airframe, sporting a six-cylinder fuel-injected 195 hp Continental IO-360-K engine and a McCauley constant-speed prop. 

It’s a 172 on steroids. In exchange for over 30 percent more power, an XP pilot will also need to pay attention to three more items: the constant-speed prop, rudder trim and cowl flap controls.

Although the airframes of the 172 and 172XP are almost identical, Cessna certified the Hawk XP (R172K) under Type Certificate No. 3A17; a different Type Certificate than the 172. Other airplanes on the 3A17 certificate include the Cessna 175 and the 172RG. The R172 E, F, G, H and J on Type Certificate No. 3A17 were sold to the U. S. and foreign armed forces and were designated the T-41B, C and D models. 

Fill the gap

The Cessna Hawk XP was Cessna’s final iteration in its nearly 30-year-long quest to build an airplane to fill the gap between the 160 hp, four-door sedan-like Cessna 172 and the big-hauling, pickup truck-like 230 hp Cessna 182. 

1,454 Hawk XPs were built over a five-year period from 1977 to 1981. It’s considered one of the most successful of the gap airplanes.

The first iteration of the more powerful 172-like models was introduced in 1958 as the Cessna 175. The exterior of the 175 looks almost exactly like the 172, except for a distinctive hump in the upper cowling. The hump in the cowling was required to accommodate the propeller reduction gear housing. The 175 had the geared Continental GO-300 series engines which produced 175 hp at 3,200 engine rpm (but only 2,400 prop rpm). Serial numbers indicate that 2,118 Cessna 175s were built.

Army and Air Force 172s

In 1964, the U. S. Army bought a version of the Cessna 172 equipped with six-cylinder, 210 hp fuel-injected Continental IO-360-D and -DB engines as the T-41B and C. The Army purchased both fixed-pitch and constant-speed propeller aircraft, and later a 28-volt version (T-41D) developed for the U. S. Military Air Program. 

The Air Force ordered Cessna 172Fs in 1964 under the T-41A designation, and would eventually shift to the 210 hp IO-360-powered versions.

U. S. forces bought 518 T-41s. FAA TCDS listings indicate that the T-41s were produced from 1964 until 1981. 

Hawk XP production

Cessna airplane production and the number of active pilots soared in the 1970s to levels that had never been seen before and likely will never be seen again. In 1975, Cessna shipped more than 15,000 airplanes; the number topped 18,000 in 1978. That equates to nearly 50 airplanes a day, every day of the year. The number of active pilots peaked at over 825,000 in 1980. 

In 1977, just before the crest of this exhilarating ride, Cessna introduced the 195 hp Hawk XP, or to be precise, a modern derated version of the T-41D. 

By the late 1970s, Cessna’s 177 Cardinal and 177RG Cardinal RG production numbers had fallen. 1978 was the last year for these “nonstandard configuration” beauties; fewer than 100 units were produced. My supposition is that Cessna’s management concluded that the Hawk XP would be an easy-to-produce and reliable 200-ish hp replacement for the Cardinals.

Cessna gauged the market correctly. The Hawk XP was a hit. Buyers bought over 700 XPs the first year on the market. The following year, an additional 204 were shipped. 

Unfortunately for the XP, for Cessna and for all other General Aviation manufacturers, the bottom was beginning to fall out of the market. The decline in U.S. gross domestic product numbers tell the tale. GDP growth was at 5.3 percent in the third quarter of 1978; by the second quarter of 1980, the GDP number had belly-flopped to a negative 1.6 percent. The recession of 1980 settled in around the world. 

Hawk XP production numbers continued to drop; just 54 airplanes left the factory at the end of production in 1981.

Hawk XP features and faults

An Aviation Consumer side-by-side comparison of the 177 and the Hawk XP reported, “The XP was, objectively, inferior to the Cardinal. The Cardinal had better handling and visibility, much more cabin room, lower cabin noise, lower maintenance costs and virtually identical performance and load-carrying ability.” The article concluded that the six-cylinder Continental engine and constant-speed prop extracted a price in reliability, maintenance and economy. 

The Hawk XP’s fuel capacity is only 52 gallons, with 49 useable. The R172K pilot operating handbook cites a fuel burn of 10.2 gph while cruising at 6,000 feet msl and 72 percent power. This setting results in 124 ktas. The result—with a one-hour fuel reserve—is a still-air range of 471 miles in 3.8 hours flight time. 

Some references cite optional fuel tanks that increase the capacity an extra 14 gallons to 66 gallons, but I haven’t been able to find any printed data confirming this option. The 172RG, which Cessna produced from 1980 until 1985, did have a 66-gallon fuel capacity—and it’s on the same TCDS. I’ve heard of owners who have installed a set of 172RG wings on their Hawk XPs, but any other method of upping the capacity to 66 gallons seems to be impossible to find. (CFA supporter Flint Aero offers STC-approved tiptanks for the R172K. The tanks add 24 gallons of capacity; 23 gallons are usable. —Ed.)

All the Hawk XPs had a 2,550-pound mtow, which yielded a useful load with average equipment of around 950 pounds. 

The POH cites ground runs of 830 feet using “short field” techniques at 2,550 pounds and temperatures of 20 C (68 F) at sea level. The book numbers show it takes nine minutes to climb to 6,000 feet msl from sea level. Climb rate is cited at 860 fpm at sea level and 540 fpm at 6,000 feet msl. 

Another place the XP shined was as a floatplane. The TCDS provides for the installation of an 80-inch propeller—instead of the 76-inch one on the XP landplane—when floats are installed. 

Corrosion: an insidious blight 

Buyers and owners should know that Cessna only applied paint to the interior skins of its single-engine airplanes that were sold with a float kit. Therefore, always be aware of the strong possibility of airframe corrosion. One of the best and easiest ways to determine if airframe corrosion is an issue is to look at the skin surface above the headliner. 

Cessna Service Newsletter (SNL) 93-3 covers what I consider to be another must-inspect airframe item. SNL 93-3 cites the possibility of sometimes extensive corrosion that may be found under the lead-vinyl sound-deadening pads glued to the inside skins of the fuselage. The best place to start inspecting for this common problem is at the skin panels forward of the forward door post and below the windshield. 

Airframe ADs

While there are 22 airframe-specific ADs for the Hawk XP, most are easy to comply with. The most important is the latest seat rail and seat inspection and replacement information in AD 2011-10-09. Worn seat rails and worn parts in the seat rail mechanism on Cessna seats need to be in excellent condition to prevent seat slippage during flight. Seats that don’t lock securely are (often fatal) accidents waiting to happen.

AD 2001-23-03 calls for repetitive inspections of the fuel line and map light wiring and switch located in and behind the left forward upper door post for burning and evidence of fuel line chafing. 

A new AD will likely be issued in the near future which calls for the inspection of the left and right lower forward door post area of Hawk XP (and many other Cessna) airframes, especially where the wing strut and built-up door post join, for corrosion and cracks. 

Engine ADs

In mid-1978, and in all Hawk XPs beginning with Serial No. 2930 in 1979, the IO-360-K engine was replaced with an IO-360-KB engine. Both engines develop 195 hp at 2,600 rpm. 

The -K engine was certified in April 1976; the -KB in March 1978. Both engines featured oil-cooled pistons and counterweight-tuned crankshafts. 

Note 10 in the engine TCDS approves the installation of any engine with a B in the suffix in place of an engine without the B suffix.

The engine Type Certificate says that the -KB is similar to the -K except for a “modified crankshaft.” This seemingly minor difference is very important.

A clue to the crankshaft modification is contained in Continental Critical Service Bulletin (CSB) 96-8 in the following sentence: “In 1978 TCM began using VAR process steel in the forging of crankshafts for use in a number of its engines. The VAR process material produces a forging with fewer impurities providing the greatest reliability and resistance to unusual operating circumstances.” 

VAR is an acronym for Vacuum Arc Remelt. Earlier crankshafts were manufactured using a process called “Airmelt.” 

The Continental CSB was followed by AD 97-26-17 titled “To prevent crankshaft failure and subsequent engine failure.” The AD required replacement of all Airmelt crankshafts with VAR crankshafts whenever the engine case halves were split for any reason at all. 

The bulletin also says that any new Continental engines built after Jan. 1, 1981, are factory-equipped with VAR crankshafts. All Continental factory-rebuilt engines after Serial No. 210114-R for -K engines and 288506-R for -KB engines had VAR crankshafts installed by the factory. 

Today, Continental sells both -K and -KB engines, and both have VAR crankshafts. According to a Continental sales person, the TBO for a -K is 1,500 hours while the -KB has a TBO of 2,000 hours. The -KB TBO can be extended out to 2,200 hours if the engine is flown 40 hours a month, according to Continental Service Information Letter SIL 98-9. There is no additional upcharge from Continental when an engine with an Airmelt crankshaft is returned as a core. Factory new and rebuilt engines sell for around $40,000.

One thing to watch out for when shopping for a Hawk XP are airplanes that have flown little in recent years because the owner wants to sell without incurring the cost to buy a new VAR crankshaft. Remember, if the engine’s case is opened for any reason (not just in case of overhaul), the crankshaft must be replaced. Though Continental won’t upcharge to swap the crankshaft as a part of a factory overhaul, third-party shops will likely charge a hefty fee. 

Another crankshaft AD was issued as emergency AD 2000-8-51 in 2000. It was shortly thereafter superseded by AD 2000-23-21. Due to manufacturing defects that may have been introduced to crankshafts built between April 1, 1998, and March 31, 2000, certain engines defined by serial number must have a core plug removed from the crankshaft prop flange to determine if the correct metallurgy exists in the crankshaft forging. Further details are in TCM Mandatory Service Bulletin (MSB) 00-5C, dated Oct. 10, 2000. Modifications

One of the most significant FAA-approved modifications for the R172K ups the engine horsepower rating from 195 hp at 2,600 rpm to 210 hp at 2,800 rpm. This STC consists of replacing the colored arcs and redline on the tachometer, changing the internal stops in the propeller and modifying the prop governor settings. This mod is sometimes referred to as the Isham mod, after Brad Isham. The upgrade is sold by Plane Tools. The website claims that the mod results in “Near Cessna Skylane performance at a fraction of the cost.”

Other notable mods include the Sportsman STOL kit for improved STOL performance. The kit contains a drooped wing leading edge, aileron gap covers and replacement wingtips. It is available from Stene Aviation in Polson, Montana. Improved cowling fastener conversion kits are available from Skybolt and from MilSpec Products.

Dollars and sense

A search at Vref, the aircraft valuation company, showed an average retail price of $61,000 for a 1979 R172K Hawk XP with 4,650 airframe hours and 1,000 hours since overhaul. A 1981 version with 4,410 airframe hours was valued at $65,000. 

Add-ons, such as the Isham mod; a WAAS-compliant navigator such as a Garmin 530W; an engine monitor such as the JPI EDM 700; and an autopilot such as the Genesys (S-TEC) 30 with altitude hold would boost the price by another $15,000 to $20,000. 

The Barnstormers aviation classifieds website listed a 1979 XP with 692 airframe hours and the Isham engine modification for $149,000. A Canadian-registered XP with a set of floats and 5,600 airframe hours is priced at $135,000 Canadian or $109,900 USD.

For comparison, Vref figures for a 1979 Cessna 172N Skyhawk show a base value of $44,000. However, this lower valuation is offset by the average airframe time of 6,200 hours. The valuation for a 1979 Cessna 182Q Skylane shows a base valuation of $85,000 with 4,150 airframe hours. 

So, there it is. The Hawk XP fits just where Cessna intended it. It hauls more, goes faster and is more powerful than the 172 of the same year, and with the Isham engine modification STC it almost does what a 182 can do (but costs less). To top it off, it’s a good floatplane. 

Sources: Aviation Consumer Used Aircraft Guide (; FAA TCDS No. 3A17, Rev. 46; Federal Reserve Bank of St. Louis (; Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California with his wife Audrey. Send questions and comments to .



AD 2011-10-09, seat rails

AD 2001-23-03, Repetitive inspection of fuel line and map light wiring and switch

AD 2000-23-21 (supersedes AD 2000-23-21), Manufacturing defect in crankshaft

AD 97-26-17 “To prevent crankshaft failure and subsequent engine failure.”


Proposed Cessna doorpost AD

The ADs and proposed AD referenced in this article are available under “Magazine Extras” in the Cessna Flyer forums at


For more Airworthiness Directives, 

visit and go to “Aviation Alerts” under the Knowledge Base menu. 


SERVICE BULLETINS Cessna Service Newsletter (SNL) 93-3


Continental Critical Service Bulletin (CSB) 96-8; Continental Service Information Letter SIL 98-9 and TCM Mandatory Service Bulletin (MSB) 00-5C



Sportsman STOL kit Knots2U, Ltd.


Stene Aviation



Flint Aero Inc.


Additional Cessna R172K modifications & STCs



210 hp “Isham” STC Plane Tools


Cowl fastener upgrades Skybolt


MilSpec Products





What Can ADS-B Out Do for Me?

What Can ADS-B Out Do for Me?


Steve Ells extols the benefits of ADS-B Out and provides information on a couple of new products in the field.

The Jan. 1, 2020 ADS-B mandate is coming for GA airplane owners. This mandate requires the installation of equipment to broadcast coded information to ATC, and to other aircraft in a format known as Automatic Dependent Surveillance-Broadcast, or ADS-B. 

Why do we need to upgrade to an ADS-B system? 

Simply put, every aircraft equipped with an ADS-B datalink will automatically transmit its precise position, its velocity (both vertical and horizontal), as well as its altitude and other information to controllers and to other nearby aircraft. 

I believe few understand how much safety is enhanced when pilots can display other nearby aircraft in real time on a panel-mounted or portable pictorial display. Prior to the installation of ADS-B Out equipment in my own aircraft, I hadn’t grasped how much this benefit would affect my sense of safety while aloft.

Is ADS-B Out required?

Does every owner need to install ADS-B Out equipment to comply with the mandate? The answer is no, but if you’re having trouble with the decision, one rule of thumb suggests that if you are now flying into and out of airspace that requires a Mode C transponder, you’ll need to equip with ADS-B Out. 

The following defines where ADS-B Out is needed after Jan. 1, 2020:

• All Class A, B and C airspace;

• All airspace at and above 10,000 feet MSL over the 48 contiguous United States and the District of

• Within 30 nautical miles of airports listed in 14 CFR §91.225, from the surface up to 10,000 feet MSL; and

• For Class E airspace over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles, at and above 3,000 feet MSL.

In versus Out

The broadcast part of ADS-B known as Out is the sticking point for mandate compliance.

Editor’s note: There is no requirement that aircraft be able to receive ADS-B In information. However, the traffic and weather information provided by ADS-B In are incredibly useful, and you will want to be able to view them in the cockpit. 

Some (but not all) ADS-B Out devices also have In capability and can display traffic and weather data on their own screens. Others can send traffic and weather data to a MFD/PFD or GPS or wirelessly to an iPad or other tablet.

If it’s just ADS-B In you’re looking for, data is easy to capture by using a wide variety of small, relatively inexpensive battery-powered portable receivers from companies such as Garmin, Dual, Appareo (Stratus), Levil and Radenna. There’s even a kit for an In receiver that features what’s known as a Raspberry Pi processor running PiAware software. 

I’ve used a portable Dual XGPS170 978 UAT receiver in the past and have recently upgraded to a Stratux Merlin by Seattle Avionics that has 978 UAT and 1090 ES receivers as well as an internal GPS and an AHRS. The Merlin AHRS provides reference information that syncs with terrain software to provide synthetic vision of the terrain. I use my Apple iPad Mini loaded with FlyQ electronic flight bag (EFB) software from Seattle Avionics to view ADS-B information.

There are still almost two years left to comply with the ADS-B Out mandate. That seems like a long time, but it’s hard to ignore the tick-tock of the clock as days speed by.

978 UAT ADS-B Out solutions

If you never fly above 18,000 feet MSL and don’t see yourself crossing international borders, then a simple 978 UAT (Universal Access Transceiver) installation is sufficient to meet the ADS-B Out mandate. 

978 UAT (operating on a frequency of 978 MHz) was enacted to provide a path for small airplane owners to comply with the ADS-B mandate without adding thousands more users to the already saturated 1090 MHz transponder frequency.

The biggest advantage of installing 978 UAT equipment is the additional bandwidth of the frequency (compared to the 1090 MHz frequency). The “bait” the FAA hung out there to convince pilots to install 978 UAT equipment is a better data transfer rate on 978 MHz and the promise of in-cabin weather and traffic info.

Recently a Palo Alto, California company called uAvionix introduced a very simple ADS-B Out system that’s so ingenious it’s laughable. The uAvionix SkyBeacon looks like the left navigation light assembly with a small white blade projecting downward. There’s almost no installation cost since all that’s required is to remove the existing nav light assembly before connecting the existing power and ground wires to the SkyBeacon. Pricing is reported to be targeted at $1,400. Alas, it’s not yet approved for installation in certified airplanes, but the folks at uAvionix assured me that the paperwork is moving through the certification grinder.

Another relatively low-cost 978 UAT solution is the Garmin GDL 82. It’s a small box with a built-in WAAS GPS receiver that is installed in line with the existing transponder coaxial cable. A supplied ADS-B antenna and coaxial cable must be installed on top of the airplane to complete the installation. It is compatible with a wide range of existing transponders. Prices start at around $1,800.

The KGX 150 line of BendixKing 978 UAT Out transmitters start at around $2,400.

The combination of low acquisition cost and simple installations removes the financial roadblock that seemed to be part and parcel of the ADS-B mandate compliance a few years ago.

1090 ES ADS-B Out solutions

If you need to fly above 18,000 feet MSL and/or travel internationally, then you must install a system that transmits on 1090 MHz to comply with the ADS-B mandate. This is often referred to as a 1090 ES system; with the ES standing for “Extended Squitter.” The following definition from an online post on the Garmin website explains squitting: “By definition, the word ‘squitter’ refers to a periodic burst or broadcast of aircraft-tracking data that is transmitted periodically by a Mode S transponder without interrogation from controller’s radar.” 

Even my ancient King KT-76A Mode C transponder shot out a three-parameter squit. A Mode S transponder can squit up to seven parameters, while ES transponders can squit up to 49 parameters of data. 

1090 ES transponders are available from Garmin, BendixKing, Appareo (Stratus), Trig and other companies. 

Is it worth it?

Prior to installing ADS-B Out equipment late last year, I flew for a couple of years displaying ADS-B In data gathered by the Dual XGPS170 mentioned earlier. Data was displayed on my iPad and I was happy to get free traffic and weather information in my cockpit. 

I installed a 1090 ES system from Trig Avionics in my own aircraft. In addition to complying with the mandate, what did I gain by installing ADS-B Out?

More than I thought I would, as it turns out. Just to verify my conclusions, I sent the following questions to around 20 of my flying friends:

1.) Why do you like ADS-B Out? 

2.) What do you feel is the real advantage of ADS-B Out? and 

3.) How do you feel ADS-B Out has enhanced ADS-B In?

Mike Jesch, a flight instructor, big iron captain for American and a Cessna 182 pilot wrote:

Why do I like ADS-B Out? What do I feel is the real advantage?

Two closely related questions. I like the Out because it improves the accuracy of the In data I receive. The real advantage is going to be the ability to receive traffic advisories in areas which don’t have radar coverage like mountainous areas. Even if not talking to ATC, it’ll be great to have accurate traffic information available in our cockpits. Once everybody gets equipped, the accuracy and validity of the data provided to the pilot in real time will be truly amazing.

ADS-B Out has and will enhance ADS-B In, by improving the accuracy and completeness of the traffic information available.

And, it’s important to remember that ADS-B In is not just about traffic. Weather information is now available in near-real time. That can provide amazing strategic planning capability in the GA cockpit.

Mike Filucci, a retired airline pilot, formation flight instructor and VP of the Pilot Information Center and Flight Ops at the Aircraft Owners and Pilots Association (AOPA) answered:

I’ve been flying my RV-4 with ADS-B In and Out for the last year and eight months (225 hours) and really like both the In and the Out features. The biggest advantage I find for the Out is really tied to the In on other airplanes—I know other pilots can see me on their screens if they are equipped with ADS-B In and, of course, I can see their airplanes because I have In. Traffic awareness is an important aspect, particularly here on the East Coast where we have a high-density environment. The other big plus of In, as you know, is the ability to see weather radar returns, albeit delayed and access weather information.

Amy Laboda, freelance writer and former editor of Women in Aviation International’s magazine, has been flying ADS-B for many years (the mandate was first published in 2010). She wrote:

This [ADS-B Out] is the only way to be sure you are getting accurate traffic info. Period. And that accurate traffic info has been enlightening. Perhaps lifesaving, but who would know, right?

I like that others know where I am, even if just seeing my 1200 squawk and a trend line. And of course, as I said above, I like having accurate traffic info on where others are if they are close to my “bubble” of airspace.

Can’t state it enough: accurate traffic position info.

It has been fascinating watching the ADS-B system build out and watching others adopt a tech that, by the time it is mandatory, I will have been using for nine years.

Eyeball-based traffic avoidance

There’s a segment of the flying public that may argue that their Mark I eyeball provides all the traffic protection they will ever need. That doesn’t work for me.

Years ago, Audrey and I were flying west up the wide and clear Antelope Valley east of Palmdale (California) VOR on our way home from one of AOPA’s famous Palm Springs Fly-ins. We were in AOPA’s completely refurbished Sweepstakes Commander 112. (For more information, see the Commander Countdown in Resources at the end of this article. —Ed.) 

Displayed on the screen of the then-new Garmin MX 20 MFD was traffic detected by the latest version of Ryan’s traffic advisory system (TAS). The screen showed four aircraft out there. We knew where they were and what altitude they were flying in relation to our altitude. We looked and looked but never saw any of them. To be honest, my eyes have needed correction since I was in fifth grade so maybe an eagle-eyed pilot could have seen them, but I remain unconvinced.

ADS-B Out enhances the ability of ADS-B In receivers to detect other airplanes 

Ken Foster, a retired engineer and pilot of a Cessna 182 who I’ve known for over 20 years wrote:

The real advantage of the system is demonstrated when you see close, sometimes very close, traffic on the panel [display] and cannot find it out the windshield. I am convinced that I have observed conflicting traffic on ADS-B and avoided a midair by varying my course. This has happened three times.

If you don’t have Out you are really not getting the In that will keep you safer. You’re kidding yourself, at least until 2020.

My experience is like Foster’s. Prior to installing ADS-B Out, I always requested flight following from ATC. Since my home airport is in a low traffic area, I almost always got it. But I knew that separating me from other traffic is pretty low on ATC’s priority of services. So, I knew that I had to keep using my “not-so-good” vision as my first defense against midair mishaps. Before ADS-B, what other tool did I have?

ADS-B Out provides a very clear picture of traffic near me. I have altered course when my “enhanced” ADS-B In showed what I felt was converging traffic. I had a transponder code for flight following during that flight, but ATC did not advise me of what I felt was conflicting traffic. 

Today I am more confident due my ability to personally control the responsibility of traffic conflict avoidance. Ensuring separation of VFR traffic is not ATC’s primary job. ADS-B Out puts the responsibility back on me; and provides just the tool I need to take care of business.

Now or later?

There are now several relatively inexpensive methods of complying with the ADS-B Out mandate. Will prices come down more in the next two years? No one knows, but avionics shops tell me that they’re busy now—so the sooner you get on a schedule to get your Out, the sooner you’ll have a tool to enhance your In experience with all its benefits, as well as the best existing tool to avoid conflicts with other airplanes. 

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, California with his wife Audrey. Send questions and comments to


Garmin, Ltd

BendixKing/Honeywell International, Inc.

Dual Electronics

Appareo Systems, LLC

Levil Aviation

Radenna, LLC

Sandia Aerospace

Seattle Avionics, Inc.

uAvionix Corporation

Trig Avionics Limited


Aircraft Owners and Pilots Association

Q&A: Alternator Belt Replacement, Fuel Burn, Alternatives for a New Spinner

Hi Steve,

I’m looking for the proper dimensions of an alternator belt—primarily the [correct] width—and maybe the original manufacturer’s name and part number. 

In about 180 hours since January of last year, we have replaced three belts on my 1981 Cessna 182 Skylane and are trying to discover the problem. 

So far, we’ve been looking at alignment, pulley smoothness and whether we have the proper belt. Do you have other ideas?



Q&A: Selecting the most suitable backcountry tire for a 182’s nosewheel, slow gear door retraction on a 210 


I own a 1965 Cessna 182 Skylane. I would like to take the plane into Utah and Idaho backcountry strips. I would restrict the 182 to 8.50 tires, not larger. I would appreciate any comments on this. I know 8.50s will work on the mains. What do you recommend on the nosegear? Do you need to reinforce the nosegear or is it possible to just install the tire as-is? 


John Patton

Mancos, Colorado 


Hi John,

Here’s what I’ve found. You can install an 8.00-6, 6-ply rating tire on your existing main landing gear wheels without any additional approval since this change is listed in the “models” section in the General section in the front of the 100-series service manual. 

This same approval permits the installation of a 6.00-6, 4-ply rating tire in the nose position. However, you’ll have to get a 6-inch wheel assembly for the nose tire change since the normal nosegear wheel is a 5-inch for a 5.00-5 tire.

A larger nosewheel fork assembly is available for installation on your 182 from Airglas in Anchorage, Alaska. It is STC’d for installation and will permit a tire of up to 8.50-6 on the nose when 8.50-6 mains are installed. 

The Airglas fork and approval paperwork costs $2,625.

Airglas cites a loss of 8 mph true airspeed following the installation of its fork and larger tires. 

In both above nosegear “up-sizes” you will have to buy a 6-inch wheel (Cleveland 40-76A is recommended). The new price for that wheel assembly is just under $700. You may be able find a good used one.

That’s all you will need to install bigger tires. However, you should be aware that your 182—in fact all 182s built between 1962 and mid-1970—have a semi-fragile firewall. These models do not have the two firewall and tunnel reinforcements that Cessna began to install in mid-1970.

I would suggest you consider installing the firewall reinforcements if you plan to do a lot of backcountry flying. It’s possible that some time in the past the service kit (SK182-44C) that includes those reinforcements was installed in the field.

It’s easy to determine if the firewall and tunnel stiffener kit has been installed. If it has, you’ll see what is called a “hat” section of metal on the forward side of the firewall. The hat section reinforcement is installed diagonally between the upper engine mount bolt on the firewall and a spot near the center of the lower firewall. Each side will have the hat section reinforcement.

If you do not have the firewall service kit installed, and you want to install it prior to flying out to unimproved strips, you will have to call a Cessna parts authority to see what the lead time and price will be. (CFA members can call the Association at 626-844-0125 for parts locating assistance. It’s a membership benefit, and we’re happy to help. —Ed.)

Due to the “weakness” of the firewall prior to the reinforcement, I also recommend that you carry 60 pounds in the baggage compartment, especially if your preflight planning shows that you’ll land with the CG in the forward portion of the envelope. 

I always carried my toolbox in the baggage compartment of my 1966 182. If there is baggage there or if one of the back seats is occupied, it’s not needed. The point is to take steps to move the center of load aft to lighten the load on the nosegear and lessen the amount of up elevator needed to pitch up to the best touchdown attitude.

I also recommend that you take a mountain flying course prior to venturing too far into the “bush.” 

Good luck and happy flying,



Hi Steve,

I’m new to Cessna 210 ownership. I’m a tractor mechanic so I understand hydraulics pretty well. My problem is that my 1966 T210F’s landing gear works great, but the gear doors are slow to retract when in flight (gear up), which tells me that the system is low on hydraulic fluid and that it takes more fluid to retract than extend.

I have filled the system according to the manual, but I think there is some stupid detail that is escaping me. Please help.

Thanks in advance,


Hi Bill, 

The T210F is a good airplane. The landing gear extension and retraction system in your 210 is the same system (with a few tiny changes) used in 210s built from 1965 through 1971.

A question for you: Do you know if the doors also open slowly?

If so, there may be air in the system. The service manual suggests actuating the gear up/gear down cycle a few times while the airplane is on jacks and hooked to a hydraulic mule. If you don’t have a mule, you can probably bleed the system by actuating the gear up and down a few times while in flight.

According to the manual, the gear up time—including doors closed—should be 10.5 seconds (+5 seconds, -0 seconds), while gear down time—including doors closed—should be 7.5 seconds (+9 seconds, -2 seconds). These times do not include the time for the gear handle to return to neutral; only the times for the gear to travel up/down and the doors to completely close.

Please let me know how many seconds it takes for the doors to close during the gear up cycle.





Thanks for the reply. The gear works normally, except when retracted the doors will stay open for a while. The amount of time varies. Sometimes it’s just a few seconds; sometimes a few minutes.


Follow-up A:

So, if everything works well except the doors don’t always close, or the closing sequence is erratic, I would first look at each of the gear up switches on the landing gear. You should find a sticky switch, or a switch that isn’t tight on its mount, or a loose wire on one of the switches.

You can double-check this supposition by checking to see if the door control solenoid (it’s located on the forward side of the power pack) is being actuated the moment all three gear are fully up in the wells. When the gears are fully up, a switch on each gear will close completing the circuit to energize the door control solenoid. You can listen for movement or feel for the movement.

Let me know what you find,



Second follow-up:


I looked at all the switches and found them to be secure and the wires good also, so I took my multimeter and found that the right main switch was intermittent and a little dirty.
I cleaned it with some contact cleaner and hit it with some WD-40 and the problem went away. I also cleaned all the switches (up and down) the same way after I came back from doing some touch and goes and everything working as it should.

As they say, “Always do the cheap stuff first.”

Thanks for your help. Do you know a place that has those switches? At some point they will need to be replaced with new parts. 50 years is pretty good service.

Thanks again,


Second follow-up A:

Hi Bill,

Glad the problem was easy and inexpensive to solve.

The part number for those switches (they’re all the same) is S1377-1. If you go to a few Cessna parts suppliers, they will advise that the new Cessna number is P6-340005. List price is $618.27. 

You can buy new old stock (NOS) switches from any one of several companies that will be listed when you do a Google search of the old part number. The search will also show vendors in used parts. Every reputable used parts dealer I know of offers a money back or exchange guarantee.

Cessna Flyer Association members can take a shortcut. Members have access to a complimentary parts locating service; which is a great help for hard-to-find parts like these switches. 

Wouldn’t hurt to have one on the shelf.



Know your FAR/AIM and check with your mechanic before starting any work.



Airglas, Inc.


Yingling Aircraft 


Cessna Flyer Association

Q&A: Eliminating the Source of Headset Noise and Installing a Davtron Clock in a C-150B

Hi Steve,

I am sick and tired of the static noise in my headset. I have been putting up with it only because I had gotten used to it, but the other day I rode in my friend’s Cessna 210—and was I surprised! His radios were clear and loud; no background static. 

What do I need to do to cut out this annoying noise in
my plane?

—Static Sally

Dear Sally,

You shouldn’t hear any static—also called radio-frequency interference (RFI) or electromagnetic interference (EMI)—if every component is in good shape and the wiring is correctly installed. 

But it does occur; sometimes you’ll notice static in the headsets after maintenance, and sometimes it can be due to component breakdown. It can even be caused if two wires are rerouted or have sagged and become too close to each other. 

Unfortunately, it’s not always easy to determine the source. 

Static noise problems require a special kind of sleuth. I know avionics techs that are always “too loaded up with work” when approached to work on a static problem—unless they installed the avionics or components themselves.

If you’re experiencing static noise only when flying in rain or near convective activity, you’re experiencing precipitation static (P-static). Obviously steering clear of intense convective activity is the first step. 

Installing static wicks on the trailing edges of the ailerons and elevators, and installing electrical bonding wiring or braiding between the control surfaces and the wings and horizontal stabilizers provides a path for the electrical charges to dissipate. 

P-static can build to the point that navigation and communication radios become ineffective, high-pitched squeals are heard, and St. Elmo’s Fire (corona discharge) is seen on the windshield. I’ve talked to Cessna pilots that have gotten quite a shocking surprise from moving their hand or arm too close to the windshield-mounted compass or OAT probe when flying under P-static conditions. 

One way to narrow down the source is to attempt to isolate the noisy circuit. You can do this by turning off circuits one at a time to see if the noise goes away; press the on/off switches (left magneto or right magneto; strobe, beacon, etc.). 

Further narrowing can be accomplished by pulling individual circuit breakers. If the noise goes away, you’ve isolated the noise-producing circuit. That’s a good start—but since there may be a number of circuits on that circuit breaker, you haven’t yet pinpointed the source. 

Once the noise-generating circuit is located, look for broken shielding connections, loose wire connections and other wiring problems. 

If your airplane has an alternator, it can be a source of static. Another common source of static is the magnetos, and a third common source is a leaky ignition harness. 

However, your noise problem can also be caused by something as small as an improperly insulated headphone jack or because the shield of the magneto P-lead is improperly grounded or has broken. The P-lead (for “Primary”) is the wire from the magneto to the Left/Right/Both switch in the instrument panel.

I recommend this first: make sure that the headphone jacks are properly insulated. Each jack should have two small plastic washers—one with a raised shoulder, and one plain—and these should be in position to prevent the body of the jack from touching the metal of the panel. 

Magneto-generated noise is generated by Bendix magnetos. If only one of your magnetos is the source of the noise, this can be detected by switching off the magnetos—JUST ONE AT A TIME—with the engine running. 

If one magneto or both magnetos are the source of the RFI, there are external filters that are easy to install. These filters cost $70 to $100 each. (Note: Installing one of these external filters on a Slick magneto will cause magneto operational problems.)

The same on/off troubleshooting can be used to determine if the alternator is producing noise in your headset. If the noise goes away, there are filters designed for alternator noise and they cost about the same as magneto filters. 

Lone Star Aviation in Mansfield, Tex. is one well-known manufacturer of these filters. In addition to its magneto and alternator filters, the company produces an Eliminator filter that’s advertised to remove noise from the DC power feed line. All Lone Star filters have FAA PMA approval for installation.

Aircraft manufacturers go to great lengths to design systems that are noise-free. However, most GA airplanes today have been subject to many equipment and wiring changes. Wiring aircraft systems does require a working knowledge of proper systems and component power, as well as grounding and shielding techniques. 

Do some troubleshooting to determine the source of the noise; take steps to eliminate it, and—if you have to—install a filter to remove the noise. 

Happy flying.

Static wicks on the trailing edges of the ailerons and elevators also help.
Electrical bonding straps between the control surfaces and the wings and horizontal stabilizers provide a path for electrical charges to dissipate

Hi Steve,

I am the happy owner of a 1962 Cessna 150B Anniversary model. I love my fastback model 150. 

I received a real nice Davtron 811 digital clock on my birthday, and although I rarely need a clock while flying, I want to install it. Isn’t it a big deal to make any kind of change to my 150?

I am very happy to just fly my simple little 150 around, so I haven’t installed any upgrades or done anything except for annual inspections and changing worn-out parts since I bought it 17 years ago. What do I need to know?

—Worried Will

Dear Will, 

Don’t worry, Will. In 2010 the FAA sent a letter to Kevin Torresdal, president at Davtron, stating, “We consider the installation of replacement clocks (including timers and stopwatches) in non-transport category airplanes to be minor changes in accordance with Title 14 Code of Federal Regulations (CFR) section (~) 21.93(a). 

“Per CFR S 21.95, copies of this letter may be given to installing mechanics as evidence that this installation is considered minor. The installation should be documented using a maintenance log book entry referencing this letter.”

The reference code for the letter is 100S-GA-10-53. (See Resources for a link to the CFA forums where you can retrieve the PDF. —Ed.)

I have a Davtron M811 clock with the elapsed time and flight time features in my airplane. Installation directions can be found on the Davtron website after selecting “M811” under “800 Series – Clocks” in the drop-down menu on the left. All that’s required is a power wire, a ground wire and a one-amp fuse. I believe Cessna installed a one-amp fuse in your airplane to provide circuit protection for the clock circuit. 

Flight time can be turned on by connecting the blue wire from the plug to an air switch, but that adds another layer of complexity. If you want the clock to provide an approximate flight time, you can connect the blue wire to the master switch. 

Each M811 clock has a small memory (“keep-alive”) battery to provide power when the airplane power is off. Davtron recommends replacing the memory battery every two years, but one way to determine if the battery is exhausted is when the flight time feature no longer works. Cost for a new battery is around $28.

Happy flying.

The M811B digital clock by Davtron is considered by the FAA to be a minor change for non-transport category aircraft. A logbook entry referencing the letter serves as sufficient documentation.
Lone Star Aviation produces an Eliminator filter to remove noise from the DC power feed line.

Know your FAR/AIM and check with your mechanic before starting any work.

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation ( and lives in Templeton, Calif. with his wife Audrey. Send questions and comments to

Noise filters
Lone Star Aviation
M811 clock
Davtron, Inc.
Clock installation reference letter
Letter 100S-GA-10-53
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