M20J Gear Retract Problem

[Costa Leite]

Is it Item Nr 29 & 30 of IPC, right?

[Ragsf15e]

40 minutes ago, Costa Leite said:

Is it Item Nr 29 & 30 of IPC, right?

 

6 hours ago, Costa Leite said:

Thanks Ragsd15e,

Can you confirm that the switch is the one highlighted in red in the pic in attach?
 

I can’t see the one you circled, but there’s two switches that hit a pad on that tube.  One is down limit, one is up.  I circled the one currently compressed (orange). The other one I can’t see in your picture but it looks the same.  Could be what you circled but I can’t tell or it looks slightly different than mine.

 

[carusoam]

Great gear limit switch details Rags!

Thanks for sharing.

Best regards,

-a-

[TerryDubYa]

Instead of using a big syringe, another way to test the airspeed limit switch is to get about 50 feet of flexible clear vinyl tubing that will fit snugly over the front of the pitot tube. Cover up the drain hole as previously described.  Feed the tubing into the cabin through the vent window and coil up the remaining length after closing off the opposite end. Select gear up and and closely watch the ASI as you carefully squeeze the coiled tubing until the gear retracts,  noting the airspeed when the beeping stops and the gear retracts.  
 

i had the same problem after an annual and, after figuring out my switch was improperly adjusted, I turned the big slotted screw on the back of the ASI and squeezed the coil until the gear retracted at 60-65 knots.  Don’t forget to take off the tape on the back of the pitot tube.  Worked like a charm.

[Phil EF]

My issue showed no annunciations, just silence when gear selected up. 
LPS 1 worked for me. 

[Costa Leite]

Just went to the hangar today to work on the switches. I never had the idea that the one piece belly was such a huge part! But it was easier to remove and replace the belly than I was first thinking when realized the dimension of this part. I managed to work without raising the aircraft on jacks. 
I send in attach pictures of the two switches. The Down-Switch was compressed and so I couldn’t exercise it.., I just sprayed it with electric contact cleaner and lubed if as I could. The Up-Switch was cleared for lub and spray and then I cycled it a few times. 
I couldn’t fly after this quick maintenance because a storm just came in, but will do the flight test on the next days and will post here the result. Let’s hope that this 1h maintenance can solve the problem!!

Thanks to all for the help. 


Cheers

Fredi

 

 

 

Edited May 17, 2021 by Costa Leite

[Costa Leite]

After two flights the problem seemed to disappear as the gear retracted without any problem after the lubrification. 
But today, on the third flight after the lubrification, I made a couple of touch and go, and on the third take-off I experienced the same situation as before. A huge delay to retract the gear (I even cycled the handle switch a few times after departure without any reaction from the gear system, except silence). Then I got the master warning light and the annunciation panel light for Gear Unsafe, but after a few seconds it finally retracted and everything came normal. 
After this episode, I decided to make another touch and go and the gear retracted immediately without any problem or warnings.
At any time I got gear aural warnings or gear bypass light. 
So, I guess the lubrification worked but maybe it was not enough?
Or maybe I need to raise the aircraft on jacks and cycle the gear to be able to lubrificante also the gear down switch (which stays compressed with the gear down compromising the lubrification and the switch cycle). 

[Ragsf15e]

1 hour ago, Costa Leite said:

After two flights the problem seemed to disappear as the gear retracted without any problem after the lubrification. 
But today, on the third flight after the lubrification, I made a couple of touch and go, and on the third take-off I experienced the same situation as before. A huge delay to retract the gear (I even cycled the handle switch a few times after departure without any reaction from the gear system, except silence). Then I got the master warning light and the annunciation panel light for Gear Unsafe, but after a few seconds it finally retracted and everything came normal. 
After this episode, I decided to make another touch and go and the gear retracted immediately without any problem or warnings.
At any time I got gear aural warnings or gear bypass light. 
So, I guess the lubrification worked but maybe it was not enough?
Or maybe I need to raise the aircraft on jacks and cycle the gear to be able to lubrificante also the gear down switch (which stays compressed with the gear down compromising the lubrification and the switch cycle). 

Or the switch is bad. Or it’s something else completely and intermittent things are a real bugger!

[carusoam]

We get plenty of failures with gear systems...

• Relays
• sensors
• Gear switch itself
• airspeed switch
• squat switch

Some things aren’t all that expensive to swap out... 

The airspeed switch can be OH’d...

Review the whole list of parts in the system, chase them down one at a time...

PP thoughts only, not a mechanic...

Best regards,

-a-

[A64Pilot]

What are you lubricating the switches with?

You really don’t want any kind of lubrication. You want to clean the contacts and ideally remove any oxidation.

‘This stuff is pricy compared to most contact cleaners, but it’s more than a cleaner, it removes oxidation, and really seems to work.

My gear intermittent extension problem ended up being the panel switch. thankfully so far the deoxit has solved the issue, good thing because limit switches are not available from Mooney. or at least the ones for my 81 model are not.

If yours won’t come up, if it’s a limit switch it’s the up limit switch if I understand the system, that switch needs to be closed to allow power to the relay, when the gear go up the switch is opened removing the power of course.

 I’d start with cleaning the panel switch as that way you don’t have to take anything apart. Spray above the lever with the switch down, and under it with it up, follow directions on the can. If that doesn’t fix it, move to the limit switches.

 

 

[PT20J]

Switch contacts are usually plated with silver to resist corrosion and lower contact resistance. They are designed with a wiping action that keeps them clean of minor tarnish. What kills them is moisture and wear. Once the thin plating wears through, the base metal tends to oxidize easily. Contact cleaner may get them going again, but expect the effect to be temporary and require repeated applications.

[A64Pilot]

This is a quote for one of my limit switches from a junkyard, yes it’s ridiculous, Yes I’m sure I can do better, but junkyard electrical parts are not my idea of a parts source, but Mooney apparently doesn’t support their aircraft, which is too bad, because there is money in parts, actually a lot of money. Assumption is that they can’t they can’t afford to, and if that’s the case, that doesn’t bode well.

Mooney parts just don’t exist it seems. I’m seriously considering selling my Mooney and getting a Bonanza or something that you can at least get parts for.

‘I’ve not been able to get one single part that I have called and checked on, not a single part. So while I don’t want to be cleaning switches, but paying 100 times what a switch should cost from a junkyard for a switch that may not be any better than mine isn’t a viable parts solution.

I can get just about any part ai want for my 75 yr old Cessna and not from Cessna, but Univair and others, I wonder why they don’t start producing Mooney parts?

 

Edited May 28, 2021 by A64Pilot

[ArtVandelay]

Here, yea, Amazon has aircraft parts.

[Ragsf15e]

2 hours ago, A64Pilot said:

This is a quote for one of my limit switches from a junkyard, yes it’s ridiculous, Yes I’m sure I can do better, but junkyard electrical parts are not my idea of a parts source, but Mooney apparently doesn’t support their aircraft, which is too bad, because there is money in parts, actually a lot of money. Assumption is that they can’t they can’t afford to, and if that’s the case, that doesn’t bode well.

Mooney parts just don’t exist it seems. I’m seriously considering selling my Mooney and getting a Bonanza or something that you can at least get parts for.

‘I’ve not been able to get one single part that I have called and checked on, not a single part. So while I don’t want to be cleaning switches, but paying 100 times what a switch should cost from a junkyard for a switch that may not be any better than mine isn’t a viable parts solution.

I can get just about any part ai want for my 75 yr old Cessna and not from Cessna, but Univair and others, I wonder why they don’t start producing Mooney parts?

 

I called Dmax and talked to him when I had my gear acting up.  He told me they have the switches available and change a few out each year.  Not sure where they get them...

[A64Pilot]

What’s Dmax? Almost always parts like this are used for other purposes and an aircraft manufacturer chooses them based on their suitability. Which of course doesn’t mean that they won’t become unavailable, but it does maybe give you another source of supply.

I had found the Amazon post, but again it’s a “used” part.

For many things like say a gear door or whatever that I can inspect visually and determine the condition, I have no issues with going used, but for something like a switch, I can’t and I have issue with using parts that I can’t determine the condition of.

[PT20J]

40 minutes ago, A64Pilot said:

What’s Dmax? Almost always parts like this are used for other purposes and an aircraft manufacturer chooses them based on their suitability. Which of course doesn’t mean that they won’t become unavailable, but it does maybe give you another source of supply.

I had found the Amazon post, but again it’s a “used” part.

For many things like say a gear door or whatever that I can inspect visually and determine the condition, I have no issues with going used, but for something like a switch, I can’t and I have issue with using parts that I can’t determine the condition of.

https://www.donmaxwell.com

Some of the MSCs that have been around for a long time know where to source almost anything. Sometimes as in the case of my fuel pressure transducer, you have to get creative at modifying an almost equivalent part and making an owner produced part. 

[A64Pilot]

Thanks, I later figured it out.

To me Dmax is short for the Duramax Diesel engine

[Costa Leite]

20 hours ago, A64Pilot said:

What are you lubricating the switches with?

You really don’t want any kind of lubrication. You want to clean the contacts and ideally remove any oxidation.

‘This stuff is pricy compared to most contact cleaners, but it’s more than a cleaner, it removes oxidation, and really seems to work.

My gear intermittent extension problem ended up being the panel switch. thankfully so far the deoxit has solved the issue, good thing because limit switches are not available from Mooney. or at least the ones for my 81 model are not.

If yours won’t come up, if it’s a limit switch it’s the up limit switch if I understand the system, that switch needs to be closed to allow power to the relay, when the gear go up the switch is opened removing the power of course.

 I’d start with cleaning the panel switch as that way you don’t have to take anything apart. Spray above the lever with the switch down, and under it with it up, follow directions on the can. If that doesn’t fix it, move to the limit switches.

 

 

Thanks A64Pilot for your feedback. 
I am glad to ear that your problem with the gear is solved! I already ordered the product you recommended. Let’s see if my problem is also with the panel gear handle switch. Later I will post here the outcome of following work on this issue. 

[A64Pilot]

I think it’s solved, as it was or is an intermittent problem, it’s still too soon to declare it solved, maybe after 50 cycles.

‘But I have another intermittent problem, the apparently infamous pulsating voltage phenomenon. I think it’s also a switch with high resistance contacts, however cleaning the switch with deoxit did no good, so I have temporarily disconnected the alternator half of the master switch and wired in a simple SPST toggle switch, and so far so good. I’ll give it a few flights and if that fixes it, I guess I’ll try to find a Mooney master switch.

Point I guess is the the miracle working deoxit did no good,so it’s not always a cure, even temporarily. 

[carusoam]

A64,

See how difficult it is to understand who has the proper credentials for swapping out switches.... and who is only a PP..?

If you want... you can list credentials in your ‘signature” line at the bottom...

Best regards,

-a-

[A64Pilot]

20 hours ago, carusoam said:

A64,

See how difficult it is to understand who has the proper credentials for swapping out switches.... and who is only a PP..?

If you want... you can list credentials in your ‘signature” line at the bottom...

Best regards,

-a-

To be honest I was not a pilot before I was an A&P, so I really don’t know the pilots limitations, but surely they are allowed to spray cleaner into a switch, so long as they aren’t removing the switch?

My journey was different than most, I took a written,  due to military experience and “poof” I was a Commercial pilot with an instrument ticket

[Costa Leite]

Wednesday I went to the hangar for a second lubrification on the up switch. This time was quicker because I already knew what to do for belly removal, antenas cables, and switch identification. I sprayed and exercised the switch several times, and with full switch movement. 
Next day I took off for beach weekend with the family, and after departure the gear retracted without any delay. 
As I did a better lubrification and switch exercise this time, I am really thinking this is a gear up switch problem, or a relay, since cycling the handle switch did not solve anything on the last issues. 

Edited June 5, 2021 by Costa Leite

[Costa Leite]

Unfortunatly, the gear retract delay problem happened again.

We have been experiencing intermittent gear retraction delays. I already lubrificated both gear limit switches several times, specially the Gear UpLimit switch which is the one that is open and free for lube and exercise when the aircraft is on ground wiht gear down, and it solves the problem for the following flight. But the retraction delay happens again on next flight.

The aircraft was placed on jacks yesterday and after long troubleshooting the problem seems to be with the Gear UpLimit Switch and not with anything else like relays or airspeed safety switch.

I clarify that when I select GearUp and nothing happens, I dont get neither the gear warning horn or the Gear Bypass button light, and even if I push the red button for airspeed safety switch override, nothing happens and the gear dont retract either. So, the problem is not with the airspeed safety switch.
In deed, the voltmeter readings on the Gear UpLimit Switch seems pointed out that the problem is with this switch.

I am now looking for 1x Gear Switch, Up Limit P/N: 1EN1S

I know there are available for sale by Mooney, but they are expensive and the lead time is severall weeks.

If someone have a spare P/N: 1EN1S, or just know somene parting out a M20J, please send me a message on Mooney Space.

 

Many thanks in advance.

Fredi 

 

[EricJ]

6 hours ago, Costa Leite said:

Unfortunatly, the gear retract delay problem happened again.

We have been experiencing intermittent gear retraction delays. I already lubrificated both gear limit switches several times, specially the Gear UpLimit switch which is the one that is open and free for lube and exercise when the aircraft is on ground wiht gear down, and it solves the problem for the following flight. But the retraction delay happens again on next flight.

The aircraft was placed on jacks yesterday and after long troubleshooting the problem seems to be with the Gear UpLimit Switch and not with anything else like relays or airspeed safety switch.

I clarify that when I select GearUp and nothing happens, I dont get neither the gear warning horn or the Gear Bypass button light, and even if I push the red button for airspeed safety switch override, nothing happens and the gear dont retract either. So, the problem is not with the airspeed safety switch.
In deed, the voltmeter readings on the Gear UpLimit Switch seems pointed out that the problem is with this switch.

I am now looking for 1x Gear Switch, Up Limit P/N: DT-2R-A7

I know there are Retrofit Kit, Gear Up Limit Switch P/N: 940112-501 for sale by Mooney, but they are expensive and the lead time is severall weeks.

If someone have a spare P/N: DT-2R-A7, or just know somene parting out a M20J, please send me a message on Mooney Space.

 

Many thanks in advance.

Fredi 

 

Looks like it is available from Newark:

https://www.newark.com/honeywell/dt-2r-a7/microswitch-pin-plunger-dpdt-10a/dp/23F4046

 

[ArtVandelay]

Looks like it is available from Newark:
https://www.newark.com/honeywell/dt-2r-a7/microswitch-pin-plunger-dpdt-10a/dp/23F4046
 

Wow, $128…that’s some switch.