Landing Gear Delay Coming Down

[Dr_Jim]

My M20C does not like to put the gear down until I have been below 100 knots for a few minutes.  Is this common?  I thought it might be gear switch but switch tested good?

 

Thoughts?
 

J

[N201MKTurbo]

If you have a squat switch, you may need new shock disks. If you have an air safety switch, it may be slow to react. When you say the switch was tested, who tested it and how did they test it?

There could also be issues with your limit switches, gear motor contactors or the motor itself.

Edited June 12, 2022 by N201MKTurbo

[Dr_Jim]

Rich,

Thanks for the feedback, not sure what a squat switch would have to do with it as my understanding is those are for gear going up.  The switch was continuity checked as it just opens and closes the circuit.  
 

I do have an air switch but think this only deals with wheels going up not down.

Might agree with problem with motor or contact but it works every time if I slow the airplane for 2 or 3 minutes

 

J

[N201MKTurbo]

23 minutes ago, Dr_Jim said:

Rich,

Thanks for the feedback, not sure what a squat switch would have to do with it as my understanding is those are for gear going up.  The switch was continuity checked as it just opens and closes the circuit.  
 

I do have an air switch but think this only deals with wheels going up not down.

Might agree with problem with motor or contact but it works every time if I slow the airplane for 2 or 3 minutes

 

J

You are correct the squat and air safety only affect going up. It is going to be difficult to troubleshoot. You could start by adding wires from the contactor fields up into the cabin with some little light bulbs soldered on so you could see if they are being commanded or not. Next time it won't go down, stomp on the floor right in front of the pilots seat. If a contactor is stuck, that may jar it loose. If you put the gear handle down, will it spontaneously lower after a minute or so?

Edited June 12, 2022 by N201MKTurbo

[Ragsf15e]

The contacter and up/down limit switches cause strange issues.  A little lps 1 and exercising the limit switches causes weird fixes.

[Yourpilotincommand]

I think I had the same problem. Mine ended up being the motor brushes. When it completely fails (it will),  make sure you know how to crank down the gear!

[carusoam]

This goes in the not normal category….

Delays for putting the gear down don’t have a standard or common reason that I am aware of….

Typical next step is putting the plane up on jacks to determine what is working and not working…

The gear doors typically help pull the gear out…

The gear itself doesn’t know how fast the plane is going except when stowing the gear, with an airspeed safety switch installed…

 

PP thoughts only, not a mechanic..

Best regards,

-a-

[Dr_Jim]

It is baffling.  On jacks it works perfectly.   

Yes, I am prepared to manually put the gear down as when this began, I had not yet unlocked the secret code (fly slow for two minutes) and manually put gear down a few times.  The airplane went to the mechanic and got a clean bill of health, gear worked fine on the ground.

Next flight something, been dealing with this for 4 years now…

Thanks for the thoughts

Jim

[A64Pilot]

Mind had a similar issue, but it wasn’t minutes and often recycling the switch a couple of times would make them come down. They always came up, up worked every time

I first replaced the landing gear relays as a few said that was likely it, but it wasn’t. In my case it turned out to be the panel mounted switch.

On mine simply spraying De-0xit in the switch returned normal operation for awhile

Try the De-oxit, easy to do and if your problem is fixed that pretty much validates it’s the switch, if no change you haven’t hurt anything 

Mine is a J but I think systems are similar

[Yetti]

First off make sure the gear is lubed well.   Second pull the actuator and lube it well.   Sounds like worn motor brushes.   They are having to vibrate to get the motor turning.   It's why when you wack motors they start working.

[Yourpilotincommand]

6 hours ago, Yetti said:

First off make sure the gear is lubed well.   Second pull the actuator and lube it well.   Sounds like worn motor brushes.   They are having to vibrate to get the motor turning.   It's why when you wack motors they start working.

There’s a AD on mine where the actuator gets inspected and lubricated.. Hopefully your IA actually did all that on the last annual. 

[Yetti]

On 6/15/2022 at 5:15 PM, Yourpilotincommand said:

There’s a AD on mine where the actuator gets inspected and lubricated.. Hopefully your IA actually did all that on the last annual. 

I have seen lots of gear that go through several(decades) of annuals and you can tell the gear has not been lubed.