Mooney landing gear failure to retract issues

[aerohawk]

A couple of months ago my 69 m20f landing gear failed to retract during takeoff at normal speed. As I continued the climb out I noticed as I got faster the landing gear would just randomly go up on its own once the aircraft hit the speed it liked.  Over the course of the next month the speed required to retract got faster and faster until it just would not retract at all.  I figured it was the airspeed safety switch since mine was still original 1968 and the problem seemed to be connected to the amount of speed the aircraft was traveling at.  So I ordered the latest and greatest replacement from mooney. Installed it with no issues.  Went flying today, and still no luck with getting the gear to retract after about 45 mins of flight time I was just flying along when out of the blue the gear retracted.  So I tried to cycle the gear and it went down, went to put it back up and no luck. So the gear stayed down for the rest of the flight. I should point out I have never had any problems with the gear going down only going up.    I was thinking it is maybe landing gear relay getting stuck.  Anyone got any thoughts?  Has anyone installed the mooney landing gear relay retrofit kit 940085-501.  My relay is the original 1968 model so I can see how it could be bad.  Any help would be appreciated.

 

 

[Marauder]

A couple of months ago my 69 m20f landing gear failed to retract during takeoff at normal speed. As I continued the climb out I noticed as I got faster the landing gear would just randomly go up on its own once the aircraft hit the speed it liked. Over the course of the next month the speed required to retract got faster and faster until it just would not retract at all. I figured it was the airspeed safety switch since mine was still original 1968 and the problem seemed to be connected to the amount of speed the aircraft was traveling at. So I ordered the latest and greatest replacement from mooney. Installed it with no issues. Went flying today, and still no luck with getting the gear to retract after about 45 mins of flight time I was just flying along when out of the blue the gear retracted. So I tried to cycle the gear and it went down, went to put it back up and no luck. So the gear stayed down for the rest of the flight. I should point out I have never had any problems with the gear going down only going up. I was thinking it is maybe landing gear relay getting stuck. Anyone got any thoughts? Has anyone installed the mooney landing gear relay retrofit kit 940085-501. My relay is the original 1968 model so I can see how it could be bad. Any help would be appreciated.

How old are your donuts? The problem you are describing is due to the donuts not expanding and hitting the squat switch.

[Marauder]

I should add that my problem first started in very cold weather. The donuts would not expand. I added the squat switch override kit and would activate that on very cold days. After a few more years the gear would retract intermittently in warmer weather. I replaced the donuts during the past annual and it has been rock solid.

[aerohawk]

I should add that my problem first started in very cold weather. The donuts would not expand. I added the squat switch override kit and would activate that on very cold days. After a few more years the gear would retract intermittently in warmer weather. I replaced the donuts during the past annual and it has been rock solid.

 

 

I have a airspeed safety switch instead of the squat switch.  The airspeed switch is brand new and appears to be operating normal.

[N201MKTurbo]

I would have to look at the schematics to tell for sure, but it may be your gear up limit switch. The normally closed contacts may not be making. I would lubricate both switches with tri flo.

[Marauder]

Has anyone installed the mooney landing gear relay retrofit kit 940085-501. My relay is the original 1968 model so I can see how it could be bad. Any help would be appreciated.

I had the over ride switch installed. I believe it is the same one for both airspeed and squat switch versions.

[Ron McBride]

Marauder

 

Do you have a copy of the 337 for the over ride switch.  I have talked to several A&P's that say that a 337 is required.  Could you post or send it to us.

 

Thank Ron

[Marauder]

Marauder Do you have a copy of the 337 for the over ride switch. I have talked to several A&P's that say that a 337 is required. Could you post or send it to us. Thank Ron

Ron -- I will go through my logs to find the entry and corresponding paperwork. It was done in the 90s and if I recall correctly, documentation was provided by Mooney to allow for the modification.

[TTaylor]

Ron -- I will go through my logs to find the entry and corresponding paperwork. It was done in the 90s and if I recall correctly, documentation was provided by Mooney to allow for the modification.

My 20F has the squat switch and the override was added and there is an updated official Mooney wiring diagram in my manuals. Manuals are at the airport but I will see if I can find the diagram when I am there this week. I had the same problem on gear not coming up until we replaced the biscuits. It is nice to have the override when you need it. I was at an empty airport in Oklahoma the first time it happened and it would have been a long flight with the gear down.

[Marauder]

My 20F has the squat switch and the override was added and there is an updated official Mooney wiring diagram in my manuals. Manuals are at the airport but I will see if I can find the diagram when I am there this week. I had the same problem on gear not coming up until we replaced the biscuits. It is nice to have the override when you need it. I was at an empty airport in Oklahoma the first time it happened and it would have been a long flight with the gear down.

 

Thanks. Between the two of us we will be able to get the paperwork to share. Flyng in WNY for years, even with healthy donuts, I found that sometimes the gear would not retract due to the extremely cold weather. I added the switch to overcome that issue. This past year i had the same issue but with much warmer temps. Since replacing the donuts at the annual, all is well.

[stevesm20b]

One more reason I like the manual gear.

[aerohawk]

I would have to look at the schematics to tell for sure, but it may be your gear up limit switch. The normally closed contacts may not be making. I would lubricate both switches with tri flo.

 

 

I checked out the up limit and while the switch seemed to be clicking and moving freely.   I put a ohm meter on the contacts going from the "common" terminal coming from the landing switch to the "NC" terminal going to the up gear relay to be 40ish ohms.  Considering that none of the other common terminals to "NC" termianls were even over 1 ohm I am pretty sure I found my problem.

[TTaylor]

Thanks. Between the two of us we will be able to get the paperwork to share. Flyng in WNY for years, even with healthy donuts, I found that sometimes the gear would not retract due to the extremely cold weather. I added the switch to overcome that issue. This past year i had the same issue but with much warmer temps. Since replacing the donuts at the annual, all is well.

Part Numbers for the override switch

 

http://mooneyspace.com/gallery/image/34460-squat-bypass-switch/