Mags not OFF

1 year 5 months ago #2778 by STEVE ELLS
Replied by STEVE ELLS on topic Mags not OFF
Hi Mike;
No, turning the key momentarily to OFF won't hurt anything at idle. In fact, it's a check most good mechanics do when they get a new airplane in for an annual inspection.

It proves that when the key is in the off position, that both mags are grounded--provided the engine does not keep running with the mag key switch in the OFF position.

When you think about it, I'll bet that the magneto key switches in at least half the GA airplanes in the fleet are worn out.

You can get a new FAA-PMA approved mag key switch from aircraft spruce: .

Good question.


Please Log in to join the conversation.

  • MIKE DAVIS's Avatar Topic Author
  • Offline
  • Subscriber
  • Subscriber
1 year 5 months ago #2766 by MIKE DAVIS
Mags not OFF was created by MIKE DAVIS
Recently in the publication General Aviation News there was an article on a the dangers of mags not off (or grounded).

Briefly, a couple flew to eat lunch at local airport. With keys in his pocket the husband and pilot got out to fuel the airplane and in the act of moving the prop to connect a tow bar the engine started and critically injured him.

The article (which was excellent) went on to say that the key ignition can become worn and it is a good idea to get in your airplane, turn the key to the right, not all the way to start, and see if the key can be pulled from the ignition. If so it may be time for a new key ignition or very least a check to make sure you're actually shutting down the magnetos.

But to my question, is it permissible, and can it cause any damage to do a magneto OFF check with the engine running. It would seem that the way to make sure your key is turning off the mags is to turn it to OFF.

Personally, I own a C182N, I checked my airplane and it's easy to turn to the R or L mag and pull the key out, so I'll be replacing the switch next week.


Mike D.

Please Log in to join the conversation.

Time to create page: 0.201 seconds