Take-off flaps setting on M20R not working unless setting full flaps first

[Yariv]

Hi,

this is my latest issue - I cannot lower the flaps to take-off setting before take-off. When I lower the flaps lever, nothing happens. I have to lower it to full flaps and then raise it up to take-off position to make it work. Raising the flaps from take-off position works fine.

it was explained to me that it involves upper limit switches and down limit switches and that in this case it is probably due to a down limit micro switch malfunction.

Has anyone experienced this before?

thanks,

Yariv

[PT20J]

Someone posted this schematic a while back. It sounds like a problem with the takeoff down limit switch.

Flap switch logic.pdf

[Yariv]

1 hour ago, PT20J said:

Someone posted this schematic a while back. It sounds like a problem with the takeoff down limit switch.

Flap switch logic.pdf 75.18 kB · 3 downloads

Thank you very much for that.

[Stephan Kablitz]

Dear Yariv, we had a similar problem on our M20J. You could not retract the flaps from full to take-off setting. Retracting completely did work however. We also were quite convinced that it would have to be a limit-switch problem. After changing the switch the problem was unchanged. We then had to learn that a cable was chewed up by a mouse that had lived behind the sidewall lining of the baggage compartment. Wouldn't hurt to have a kook, I think...

[Yariv]

Thanks Stephan. I hope it’s not the case here as my airplane sits in a hangar with cowl plugs in place. I’ll update the thread in July after the airplane comes back from its annual inspection.

[skykrawler]

Don't some of the newer models have 3 commanded flap position (rather than continuous)?  There was a bulletin to convert to that design which had an additional switch installed in the back.   Is this one of those models?

 

[Yariv]

On 5/14/2024 at 3:32 AM, skykrawler said:

Don't some of the newer models have 3 commanded flap position (rather than continuous)?  There was a bulletin to convert to that design which had an additional switch installed in the back.   Is this one of those models?

 

It is the original design, 3 position flap lever - up, take-off, and full flaps.