Gear didn’t come up

[RobertGary1]

Pulled the gear handle departing in fog and instead of the gear coming up I got the unsafe light and the audio alarm. Is this the plane thinking it was still squat? My donuts measures in spec but are older. Is it true that earn donuts can cause the gear to do descend enough to squat the switch?   

[GeeBee]

Check your emergency extension handle. 

[RobertGary1]

12 minutes ago, GeeBee said:

Check your emergency extension handle. 

I don’t have a sensor on it. 

[mike_elliott]

In cold wx if yours has a squat switch, older donuts won't expand and open the switch. Eventually they will, but it might be 50 nm or so. Fix are new donuts

 

[EricJ]

52 minutes ago, RobertGary1 said:

Pulled the year handle departing in fog and instead of the gear coming up I got the unsafe light and the audio alarm. Is this the plane thinking it was still squat? My donuts measures in spec but are older. Is it true that earn donuts can cause the gear to do descend enough to squat the switch?   

That's the likely explanation if you have a squat switch and no bypass.   Did you leave the handle up to see if it eventually expanded and flipped the switch if cold?

[RobertGary1]

4 minutes ago, EricJ said:

That's the likely explanation if you have a squat switch and no bypass.   Did you leave the handle up to see if it eventually expanded and flipped the switch if cold?

I left it up for a bit with no change. But cycling the switch brought them up. Then they were fine through several more cycles. 

[Hank]

2 hours ago, mike_elliott said:

In cold wx if yours has a squat switch, older donuts won't expand and open the switch. Eventually they will, but it might be 50 nm or so. Fix are new donuts

I was having intermittent problems with this, listening to that awful squall for up to 15-20 minutes. New donuts in late 2012 have slowed the problem, not even an issue this weekend in super cold, WV-like temperatures down in Sweet Home.

You can check the pucks, their manufacture date (month / year) is molded into the edge. Being upside down, I thought mine spread "09/96" but after removal, it was "06/69" and my landings improved significantly! 

[Ragsf15e]

1 hour ago, RobertGary1 said:

I left it up for a bit with no change. But cycling the switch brought them up. Then they were fine through several more cycles. 

Step one - does your airplane have a squat switch?  Most don’t, only a few years.  It’s in left gear well if you do.

 

You can pull the gear warning circuit breaker to shut off the warning and let your brain think if the problem reoccurs.   That warning is designed to be distracting and it works!

[RobertGary1]

2 hours ago, Ragsf15e said:

Step one - does your airplane have a squat switch?  Most don’t, only a few years.  It’s in left gear well if you do.

 

You can pull the gear warning circuit breaker to shut off the warning and let your brain think if the problem reoccurs.   That warning is designed to be distracting and it works!

I have the unsquat switch on the left main 

[carusoam]

Cold weather and unsquat switches, and old donuts…

Combine together to behave this way…. 

a decade + of MS experiences combined in one place!

Go MS!

Best regards,

-a-

[Ragsf15e]

53 minutes ago, RobertGary1 said:

I have the unsquat switch on the left main 

Well the donuts could be involved then.  I’ve heard some had an airspeed switch too?  Do you know if you have both?

Doesnt help you now, but Mooney has a service letter and kit that installs a bypass switch which allows you to get the gear up if the squat switch fails. @Marauder has good pictures.  Sometimes it happens when it’s really cold.

[N201MKTurbo]

Don’t discount the contactors. I have found if it is the contactors, a good jolt will get them going. Considering they are mounted under the pilots seat, a good stomp on the floor as close to the front of the seat as you can manage will usually get them going.

[RobertGary1]

7 minutes ago, N201MKTurbo said:

Don’t discount the contactors. I have found if it is the contactors, a good jolt will get them going. Considering they are mounted under the pilots seat, a good stomp on the floor as close to the front of the seat as you can manage will usually get them going.

That’s the limit switches. I don’t think they can affect this. I lube all three switches at annual. 

[N201MKTurbo]

10 minutes ago, RobertGary1 said:

That’s the limit switches. I don’t think they can affect this. I lube all three switches at annual. 

I’m not talking about the limit switches, I’m talking about the contactors, you know, the giant relays that reverse the power to the gear actuator. Inside them are big copper washers that are moved by the solenoids. When they get old, pitted and oxidized, they may not conduct when held against the contacts, a little friendly persuasion will move them enough that they will conduct and the motor will run.

[RobertGary1]

10 minutes ago, N201MKTurbo said:

I’m not talking about the limit switches, I’m talking about the contactors, you know, the giant relays that reverse the power to the gear actuator. Inside them are big copper washers that are moved by the solenoids. When they get old, pitted and oxidized, they may not conduct when held against the contacts, a little friendly persuasion will move them enough that they will conduct and the motor will run.

Because the gear alarm and the unsafe light came on when I moved the gear switch I’m thinking it may be the squat switch.  

[RobertGary1]

This was the first time I’d heard the gear alarm go off with the power at full.  I suppose that’s what would happen if you tried to tuck the gear while on the ground???

[Marauder]

This was the first time I’d heard the gear alarm go off with the power at full.  I suppose that’s what would happen if you tried to tuck the gear while on the ground???

Exactly. Your 76 probably has the same style switch as my 75. I used to get a “gear unsafe” and an alarm when mine failed. I used to fly out of Buffalo and a few Januarys we never got above freezing. Even with fresher donuts and properly spaced, occasionally it would still trigger.



Mooney offered a retrofit kit for the pre J models. I believe this override switch came standard on the 77 model Js.




Sent from my iPad using Tapatalk Pro

[carusoam]

Great pics Marauder!
 

-a-

[RobertGary1]

Any idea on the effort to install the override? Is it a simple install ?

[A64Pilot]

I had a similar problem, but mine was they wouldn’t come down, first replaced the relays, then chased limit switches, ended up in my case being the panel mounted switch. 

If I recycled the switch that usually brought them down, you recycling yours and that worked seems to indicate switch.

Buy some Deoxit and spray the interior of the panel mounted switch,( follow the directions), if that helps replace the switch, cleaning is a temporary fix. If anything Deoxit will help extend the life of a switch so if it’s not the switch you didn’t hurt the switch by cleaning it.

I’d put the aircraft on jacks and see if I could replicate the problem, if I could then I’d try bypassing the squat switch and see if that fixes it.

I’m afraid you may have to start with most likely and check each part.

In my case I got no alarm, no unsafe light etc, they just didn’t come down. I got no warnings I’m sure because electrically nothing was done when the switch was placed in the down position.

[EricJ]

2 hours ago, RobertGary1 said:

Any idea on the effort to install the override? Is it a simple install ?

The kit removes the squat switch and replaces it with the airspeed switch and adds the bypass switch so that you can still swing the gear on the ground.

I don't think it would be awful to install, but not trivial.   The bigger problem might be finding the kit, and it might be easier to find the parts used, especially the airspeed switch.  It does completely solve the issue with cold pucks.

[RobertGary1]

26 minutes ago, EricJ said:

The kit removes the squat switch and replaces it with the airspeed switch and adds the bypass switch so that you can still swing the gear on the ground.

I don't think it would be awful to install, but not trivial.   The bigger problem might be finding the kit, and it might be easier to find the parts used, especially the airspeed switch.  It does completely solve the issue with cold pucks.

That’s not the kit I’m looking at. 
it just adds a button. 
https://www.mooney.com/wp-content/uploads/2020/12/SBM20-196A.pdf

[RobertGary1]

8 hours ago, Marauder said:

Exactly. Your 76 probably has the same style switch as my 75. I used to get a “gear unsafe” and an alarm when mine failed. I used to fly out of Buffalo and a few Januarys we never got above freezing. Even with fresher donuts and properly spaced, occasionally it would still trigger.



Mooney offered a retrofit kit for the pre J models. I believe this override switch came standard on the 77 model Js.




Sent from my iPad using Tapatalk Pro

You also have my same voice annunciator haha 

[RobertGary1]

2 hours ago, A64Pilot said:

I had a similar problem, but mine was they wouldn’t come down, first replaced the relays, then chased limit switches, ended up in my case being the panel mounted switch. 

If I recycled the switch that usually brought them down, you recycling yours and that worked seems to indicate switch.

Buy some Deoxit and spray the interior of the panel mounted switch,( follow the directions), if that helps replace the switch, cleaning is a temporary fix. If anything Deoxit will help extend the life of a switch so if it’s not the switch you didn’t hurt the switch by cleaning it.

I’d put the aircraft on jacks and see if I could replicate the problem, if I could then I’d try bypassing the squat switch and see if that fixes it.

I’m afraid you may have to start with most likely and check each part.

In my case I got no alarm, no unsafe light etc, they just didn’t come down. I got no warnings I’m sure because electrically nothing was done when the switch was placed in the down position.

That’s not similar to my issue. My handle works great. I put the switch in the up position and alarms started going off. It knew the switch was up. 

[EricJ]

18 minutes ago, RobertGary1 said:

That’s not the kit I’m looking at. 
it just adds a button. 
https://www.mooney.com/wp-content/uploads/2020/12/SBM20-196A.pdf

Even better!   I'd forgotten that that was available to add without the airspeed switch.    That's not a difficult mod, per the SBM, and it would cure the problem of waiting for the donuts to expand.