landing gear troubleshooting

[Guest Mike261]

anyone ever seen this:

landing gear functions fine, comes up and down quickly.

every so often it won't cycle up. 

only happens on the up cycle.

changed gear switch and up limit switch.

its intermittent...happens only once in a while.

on some flights its happened twice.

Ideas?

Mike

[ArtVandelay]

Even if you push the bypass button?

[Guest Mike261]

1 hour ago, teejayevans said:

Even if you push the bypass button?

yes, the bypass button doesn't help, so i think the pitot static switch is ok.

i'm leaning to the motor brushes, but wanted to see if anyone has already figured this one out.

 

[carusoam]

You have the airspeed switch?

or 

You have the squat switch?

the devices that sense that you are going fast enough and allows the retract mechanism to do it's job...

If they are mis sensing, they may make it a challenge to get the gear to move...

But, the override switch should override a faulty airspeed switch...

Limit switches are also a good idea to clean, just because they are known to get dirty and stop working properly...

Better to work on the ground for this to see what's working and what's not.

PP observations only.  Not a mechanic.

Best regards,

-a-

 

[dlthig]

Have you checked the continuity of your wires? Many years ago I flew a Comanche with an intermittent gear problem. It was popping the circuit breaker. The owner spent quite a bit of time and money with no success until he crawled under the panel with a multi-meter and found a wire that was chafing. Also, what Carusoam said about the limit switches. An Arrow I flew had gear issues until the mechanic crawled under it with some fine sandpaper and cleaned the switches. Good luck.

[Guest Mike261]

The limits have been serviced. My mooney has the airspeed switch mounted behind the airspeed indicator. I tried the override switch as published in the manual and it didn't change anything on a few occasions when the gear would not retract.

funny that it only happens on retract, not extension...this would lead me to believe its something in the retract portion of the circuit. mechanic troubleshot and swung the gear about 45 times on the ground with only two failure to retracts. 

There is nothing more frustrating than in intermittent electrical problem, as an electrician I've pulled more than a few hairs out on the job.

Mike

[nels]

Does it trip the breaker when it doesn't retract?

[rgpilot]

I had a similar problem with my old J. After checking everything else, I thought it might be the up limit switch. Exercised the switch multiple times (used the wooden handle of a hammer to plush it in. There is a very strong spring to push against.) Problem solved. You don't  need to jack the plane. It's easily accesses with the plane on the ground.

[nels]

This is ironic but yesterday I took off in my J and cycled the flaps and gear up and noticed I still had the green light on the panel for the gear down. The floor window said it was still down so I asked the tower and they verified down. I landed and tied the plane down thinking this plane is going to be expensive. I started home then remembered that I had gone through the emergency manual gear sequence last week in a "touchie feelie" type of way and had pulled the breaker as part of my exercise. I sure thought I would have reset the breaker but probably didn't. I went back to the plane and sure enough the breaker was out.  Now I'm afraid to take off and cycle the gear up as maybe it won't come back down.

Sorry, Mike,  I know this isn't helping you out but just wondering if your breaker had popped out as I mentioned in my previous post.

[Guest Mike261]

Turns out bad motor.

sent out the actuator...

it needed a new no back spring, new motor, and had all SB's applied. 

2.2 AMU

Now it has to be re-installed.

Mike

[carusoam]

Mike,

Any idea how many hours are on the airframe?

Not that age or AF hours has much to do with that motor or the spring.

Get a good look at the old spring.  See if it has any surface cracks that are visible on it.

Best regards,

-a-

[Guest Mike261]

9 hours ago, carusoam said:

Mike,

Any idea how many hours are on the airframe?

Not that age or AF hours has much to do with that motor or the spring.

Get a good look at the old spring.  See if it has any surface cracks that are visible on it.

Best regards,

-a-

3300 on the airframe.

The motor was original. The spring was at its 1000 hr life limit.

I don't know if the old parts will come back with the actuator...i assume they will. The A/P sent the actuator out for overhaul. 

I do know that the condition of the motor was not very good, I'm told it was probably a short matter of time until the intermittant nature of the problem became permanent.

If the parts don't come back, (I assume there is a core value for the motor, they are rebuildable) and i can't determine the nature of the problems from the paperwork i will call the guy and get the lowdown and pass the info along here. 

at least i don't have to think about the no back spring for another 1000 hours. I hope there are no infant mortality issues with the new spring.

Mike

[cnoe]

1 hour ago, Mike261 said:

The motor was original. The spring was at its 1000 hr life limit.

... at least i don't have to think about the no back spring for another 1000 hours. I hope there are no infant mortality issues with the new spring.

Oh no, here we go again!

Camguard, LOP, and no-back-springs. Gotta love 'em!

[Guest Mike261]

3 hours ago, Hyett6420 said:

Why a new no back spring?  Check my post on this issue.  

Also why a new motor and not new brushes, which is a simple job.  If the motor goes down then it will go up.  However if the brushes are worn then the twisting force of up is different to down and would affect the way the  brushes contact the motor shaft while the wiring on the motor wont have changed.

im a PP and not a mechanic but i DO understand the Mooney gear system well. . 

For my mind and from what you have said there is an issue with the brushes nothing else.  The no back spring does not need to be replaced except every 1k hours.  

Andrew

copied from thé SB:

GENERAL:

After disassembly, clean clutch, gears, “No Back” Clutch spring and housing thoroughly. Discard screws (3 & 4). Discard old “No-Back” Clutch Spring if crack is found after compliance with INSPECTION OF “NO BACK” CLUTCH SPRING below or if 1000 Hour Removal & Replacement is being accomplished.