1971 M20C - Electric Gear Failed to Lower

[oisiaa]

After a few touch & gos the gear decided that it wanted to stay up on me. Fortunately the manual extension system did its thing and got the wheels down and locked. I haven't had it looked at yet to see what the cause might be. 

How often do these types of issues happen and is there a common failure mode? Any leads that I can pass to the A&P would be helpful in getting started in the right direction. 

I'll keep this thread updated as the inspection and repair goes on. 

Edited Tuesday at 01:33 AM by oisiaa

[PT20J]

Usually a relay or a microswitch. There are a bunch of past threads on this and a current one 

 

[Ragsf15e]

1 hour ago, oisiaa said:

After a few touch & gos the gear decided that it wanted to stay up on me. Fortunately the manual extension system did its thing and got the wheels down and locked. I haven't had it looked at yet to see what the cause might be. 

How often do these types of issues happen and is there a common failure mode? Any leads that I can pass to the A&P would be helpful in getting started in the right direction. 

I'll keep this thread updated as the inspection and repair goes on. 

The other threads will be useful, but yours may be wired slightly differently. You should look at the wiring diagram in the electrical schematic for your year group. It is probably in the end of the maintenance manual. You definitely have some type of limit switches in those can be a common source of failure.

[Hank]

My only gear trouble was after an electrical failure; a component on the circuit board behind the panel rheostar blew and took out everything electric on approach just after breaking out and turning inbound, and the second time the alternator died, flaps went down slowly, couldn't transmit and then gear didn't move.

Both times, emergency extension worked just fine.

But like I did, you'll have to investigate to find the root cause. Good luck!

[oisiaa]

Thanks for the information and link to the other post. I'm hopeful that it might just be a microswitch or relay issue. I'll keep this thread updated as another resource for posterity.