M20j gear won’t retract above 80KT

[Jim D]

Hi all,

My father’s 1983 M20J has a problem that’s been dogging the mechanics.   The gear does not retract if the airspeed is above 80 KT.  The pressure switch has been replaced, and the gear will swing all day long on the jacks.  Any Thoughts.

 

Jim

[N201MKTurbo]

Will it retract if you push the button? 

Do you have to push he button when it is on jacks?

[Jim D]

Squat override doesn’t seem to help.  

[xcrmckenna]

The pressure switch does have an adjustment for different speeds. Any chance they didn’t get that right when the changed it?


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[Yetti]

Need more information.    does the motor run?  Do unsafe lights come on?   Breakers pop?   Sounds like they reversed the wiring on the safety switch.... not sure how that is possible.

[bradp]

Gear swings okay with the override switch pressed on jacks but not in the air?

Does your mechanic have a pitot test setup? You can reproduce the air on the ground that way.  

Get the wiring diagram for the airspeed switch and test that output first with the pitot test apparatus.  

The fact that the gear override switch does not work makes it seem like something is amiss within that circuit. 

Just PP thoughts like Anthony has....

[AaronDC8402]

I don't think I've ever looked closely at what airspeed I put the gear up, but I bet I've never gotten to 80 kts before flipping the switch.

 

[Piloto]

17 hours ago, Jim D said:

Hi all,

My father’s 1983 M20J has a problem that’s been dogging the mechanics.   The gear does not retract if the airspeed is above 80 KT.  The pressure switch has been replaced, and the gear will swing all day long on the jacks.  Any Thoughts.

 

Jim

The gear should no retract if the speed is less than 80kts. Check the switch wiring.

José

[Bob - S50]

Maybe the airspeed switch is hooked up backwards?  That is, instead of preventing gear retraction below 80 KIAS, it is preventing retraction above 80 KIAS.  I don't know how it works and I'm too lazy to look it up, but I assume the airspeed completes or breaks an electrical circuit which allows the gear to retract.  Maybe you have the positive and ground reversed?

[mooniac15u]

20 hours ago, Piloto said:

The gear should no retract if the speed is less than 80kts. Check the switch wiring.

José

The maintenance manual specifies 60 +/- 5 KIAS for the airspeed switch.

[bradp]

Are the airspeed switches adjustable?  I've taken a look at mine and I couldn't tell you how it's done just by looking at the thing. 

So normal operation is below 60+/-5 no go; 

Sounds like the airspeed switch is perhaps reverse wired **and** it needs to be adjusted downward.

Could this be an issue since overhaul of the airspeed switch or is it the same symptoms before and after it was replaced...? Any recent maintenance issues or fixes or did this pop up all of a sudden?

Regardless something is not right about the airspeed override switch; if on jacks you should be able to retract your gear despite airspeed below threshold with that bypass switch.

Look at @201er's latest youtube - probably the longest single mooney gear swing video on youtube.