Gear not going up

[BillYesIAm]

Hi,

Back again with another issue that I’m thinking there might be some knowledge here to help me figure this out, so here goes.

AIRCRAFT: 1976 M20C. Electric gear. Squat switch removed.

PROBLEM: So far the gear has always come up on takeoff but it is inconsistent as to how long it takes to come up. The gear goes down correctly. About half the time that I bring the gear switch to the up position the gear comes right up. The rest of the time it takes between 15 seconds to as long as six minutes (yesterday) before the gear comes up. It does not come up slowly, it does not grind, or bind up, or struggle or anything like that. It just stays down, but when it finally comes up it just comes up in a normal smooth manner, taking a couple of seconds like it is supposed to.

We ran a quick test on it at AGL Aviation when I was up there for the rigging. Putting a little air to the pitot tube until 85 mph was showing on the ASI, it came right up. I told Lynn that I would bring it back up when I had time if the problem continued.

I have tried jiggling the gear switch and actually putting it in the down position and then back up into the up position to see if maybe it might be something in the switch but none of that has ever helped. It just comes up when it is ready to.

I might get up there to see him next week but in the meantime I thought I would take this rainy afternoon to put this out there to you guys just to maybe get some ideas of what the culprit may be.

R/Bill Magill Moncks Corner SC

[Andy95W]

Old, sticky up relay.

[kortopates]

sounds like the circuit through the air speed safety switch. does your installation have red lighted button to bypass the safety switch? sound like you don’t.
You can follow your schematic to trace out that circuit and see if the switch might be intermittent.


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[Ragsf15e]

30 minutes ago, BillYesIAm said:

Hi,

Back again with another issue that I’m thinking there might be some knowledge here to help me figure this out, so here goes.

AIRCRAFT: 1976 M20C. Electric gear. Squat switch removed.

PROBLEM: So far the gear has always come up on takeoff but it is inconsistent as to how long it takes to come up. The gear goes down correctly. About half the time that I bring the gear switch to the up position the gear comes right up. The rest of the time it takes between 15 seconds to as long as six minutes (yesterday) before the gear comes up. It does not come up slowly, it does not grind, or bind up, or struggle or anything like that. It just stays down, but when it finally comes up it just comes up in a normal smooth manner, taking a couple of seconds like it is supposed to.

We ran a quick test on it at AGL Aviation when I was up there for the rigging. Putting a little air to the pitot tube until 85 mph was showing on the ASI, it came right up. I told Lynn that I would bring it back up when I had time if the problem continued.

I have tried jiggling the gear switch and actually putting it in the down position and then back up into the up position to see if maybe it might be something in the switch but none of that has ever helped. It just comes up when it is ready to.

I might get up there to see him next week but in the meantime I thought I would take this rainy afternoon to put this out there to you guys just to maybe get some ideas of what the culprit may be.

R/Bill Magill Moncks Corner SC

To expound on the above… the most likely culprits are the airspeed safety switch or the up/down relays.  If you select gear up right after takeoff, it might not come up immediately due to low airspeed, but should then come up above ~85ish.    That wouldn’t explain it staying down for 10 minutes.  If you take off the belly panels (roughly under the backseat foot area), you’ll find two switches, up/down relays.  They feed into a solenoid near the motor.  There’s been lots of success spraying some lube into these switches and “exercising” them.  One will be already compressed by the gear, the other will be open.  Lube and exercise both.  There’s a picture on another thread, I’ll look.

[Ragsf15e]

Here, read this thread.  It’s got pictures and more descriptions.

https://mooneyspace.com/topic/38540-m20j-gear-retract-problem/page/2/
 

[Marauder]

And if you don’t have the red button, I’d see if you can get the kit. It’s worth having.





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[Ragsf15e]

14 minutes ago, Marauder said:

And if you don’t have the red button, I’d see if you can get the kit. It’s worth having.





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I didn’t realize that was a kit.  What else is there besides a red button?  You’re right about it being nice… it hasn’t happened often, but I really wanted one of those when my gear was stuck down on the west side of the cascades and my home base is on the east side.  

[Marauder]

I didn’t realize that was a kit.  What else is there besides a red button?  You’re right about it being nice… it hasn’t happened often, but I really wanted one of those when my gear was stuck down on the west side of the cascades and my home base is on the east side.  

Mooney offered it as retrofit kit back when I did it in the 1990s. I’ll see if I can find the logbook entry. I also did a full wiring schematic of how it was wired into the system.

I hear you about the value. I flew for years out of WNY. If it got bone chilling cold the donuts wouldn’t expand enough to activate my mechanical squat switch. I got stuck flying home with the gear down after an overnight stay. Flying 200 miles at 100 knots sucked. Reminded me of my days flying a Cessna.

Let me see what I can dig up.


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[Marauder]

45 minutes ago, Ragsf15e said:

I didn’t realize that was a kit.  What else is there besides a red button?  You’re right about it being nice… it hasn’t happened often, but I really wanted one of those when my gear was stuck down on the west side of the cascades and my home base is on the east side.  

Kit was under SB-196 (SBM20-196A.pdf (mooney.com)). I also did a hand drawing of the wiring to make it easier for me to visualize everything. There are differences in the kits for the various Mooney models it covers. I'll post the wire diagram I made. The SB has the same information but does it a bit more piecemeal. 

[Marauder]

I’ll scan it to a pdf and send it to you as well.


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[BillYesIAm]

On 3/16/2022 at 3:47 PM, Andy95W said:

Old, sticky up relay.

Probably. Thanks

[BillYesIAm]

On 3/16/2022 at 3:49 PM, kortopates said:

sounds like the circuit through the air speed safety switch. does your installation have red lighted button to bypass the safety switch? sound like you don’t.
You can follow your schematic to trace out that circuit and see if the switch might be intermittent.


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I do not have the red bypass button, but it looks like something I might should look into after I get the current issue straightened out. Thank you.

[BillYesIAm]

On 3/16/2022 at 3:57 PM, Ragsf15e said:

To expound on the above… the most likely culprits are the airspeed safety switch or the up/down relays.  If you select gear up right after takeoff, it might not come up immediately due to low airspeed, but should then come up above ~85ish.    That wouldn’t explain it staying down for 10 minutes.  If you take off the belly panels (roughly under the backseat foot area), you’ll find two switches, up/down relays.  They feed into a solenoid near the motor.  There’s been lots of success spraying some lube into these switches and “exercising” them.  One will be already compressed by the gear, the other will be open.  Lube and exercise both.  There’s a picture on another thread, I’ll look.

Lots of good info. Thanks. I am going up to AGL Aviation next week and I imagine this is one of the things we will look into. Love this site. Always learning new stuff.

[David Lloyd]

Bill, you and Lynn get it figured out, I'll be there the following week.

[BillYesIAm]

On 3/18/2022 at 7:55 AM, David Lloyd said:

Bill, you and Lynn get it figured out, I'll be there the following week.

David, As usual Lynn got it figured out. It was the airspeed safety device that is located right in the back of the ASI. He found loose tubing, fixed that, then adjusted the screw so it goes up right up at 85 mph. Thank you again to everybody on this forum and of course thank you to AGL for again making it easy for me. On a sidenote, flying back from Morganton to Charleston (actually Moncks Corner) was one of the worst turbulence days I’ve flown in for a while. I was VFR so I experimented at 5500, then went down to 3500, then back up to 7500. Never did find smooth air all the way down to the surface at MKS. Anyway, I took the auto pilot off and IT gave me a lot of practice on maintaining a heading and altitude.

Bill

76 M20C N7070V