When should the landing gear motor be inspected?

[Stephen Skinner]

When should the landing gear motor be inspected and who would be the best person to take it too?

I have an ITT gear motor LA11C2115 and I believe 40:1 gears by the time it takes for the gear to extend or retract (Takes 5-6 seconds)

Do the brushes ever wear out and need replacement?

Has anyone ever had the gear motor fail?

The 25 AMP Circuit Breaker for the gear motor is being replaced due to coming apart and popped once. This makes me wonder if it was just the CB or if the motor is trying to tell me something?

Thanks,

Steve

 

[Bob - S50]

We had one instance of the gear failing to extend electrically.  Our mechanic put it on jacks and cycled the gear numerous times.  Could not duplicate.  No problems since.  Our guess is that there is a dead spot on the armature and the motor just happened to stop on that spot during retraction prior to the extension problem.

We are pulling the motor during annual (next week).  Our mechanic is sending it to a place in Sacramento for OH.  Don't know the name of the place but I can find out if you need it.

[kortopates]

3 minutes ago, Bob - S50 said:

We had one instance of the gear failing to extend electrically.  Our mechanic put it on jacks and cycled the gear numerous times.  Could not duplicate.  No problems since.  Our guess is that there is a dead spot on the armature and the motor just happened to stop on that spot during retraction prior to the extension problem.

We are pulling the motor during annual (next week).  Our mechanic is sending it to a place in Sacramento for OH.  Don't know the name of the place but I can find out if you need it.

That would be George's Electrical Service in Sacramento (916-927-3386)  that can overhaul the motor - a great resource when it needs it.

Prior to that, I'd check with LASAR or Top Gun for their advice. (I don't know the specifics for ITT gear motor but LASAR & Top Gun are popular shops for replacing the no back clutch spring and other maintenance on these).

[ArtVandelay]

That would be George's Electrical Service in Sacramento (916-927-3386)  that can overhaul the motor - a great resource when it needs it.

I vaguely remember that the guy (George?) was going to retire, anyone confirm my recollection?


Tom

[Bob - S50]

6 hours ago, kortopates said:

That would be George's Electrical Service in Sacramento (916-927-3386)  that can overhaul the motor - a great resource when it needs it.

Prior to that, I'd check with LASAR or Top Gun for their advice. (I don't know the specifics for ITT gear motor but LASAR & Top Gun are popular shops for replacing the no back clutch spring and other maintenance on these).

That's the guy.  We had the spring replaced almost 1000 hours ago by the MSC at Troutdale (TTD).  We'll probably have to have him do it again some time this coming year.

[Htwjr]

My landing gear motor gets inspected daily and I can tell if there are any issues with it before I get to the airport.  Its my right arm.

[M20F]

I inspect my right shoulder in the mirror every morning.  Still a sweet piece of steel wrapped in flesh. 

[Yetti]

On 12/9/2019 at 4:48 PM, kortopates said:

That would be George's Electrical Service in Sacramento (916-927-3386)  that can overhaul the motor - a great resource when it needs it.

Prior to that, I'd check with LASAR or Top Gun for their advice. (I don't know the specifics for ITT gear motor but LASAR & Top Gun are popular shops for replacing the no back clutch spring and other maintenance on these).

Don't do it.  See if Aeromotors will do it.   We have had to rescue 3 actuators out of his shop and LASAR.   He incorrectly says the E gear Actuator is not serviceable.  

And the breaker is supposed to be a 15 amp not 25 amp.

Make sure all the gear is lubed well.   Take the gear box apart and lube everything well with the special grease.  More years of flying service awaits you.   Any AP should be able to lube a gear box.  Make sure all the shims go back in the same way.

[Guitarmaster]

We had one instance of the gear failing to extend electrically.  Our mechanic put it on jacks and cycled the gear numerous times.  Could not duplicate.  No problems since.  Our guess is that there is a dead spot on the armature and the motor just happened to stop on that spot during retraction prior to the extension problem.
We are pulling the motor during annual (next week).  Our mechanic is sending it to a place in Sacramento for OH.  Don't know the name of the place but I can find out if you need it.

Was it cold when you had the problem?

Sent from my Pixel 2 XL using Tapatalk

[Bob - S50]

Just now, Guitarmaster said:

Was it cold when you had the problem?

Sent from my Pixel 2 XL using Tapatalk
 

No.  If I remember right it happened in August, the only 'hot' month in Seattle.

[kortopates]

5 hours ago, Yetti said:

Don't do it.  See if Aeromotors will do it.   We have had to rescue 3 actuators out of his shop and LASAR.   He incorrectly says the E gear Actuator is not serviceable.  

And the breaker is supposed to be a 15 amp not 25 amp.

Make sure all the gear is lubed well.   Take the gear box apart and lube everything well with the special grease.  More years of flying service awaits you.   Any AP should be able to lube a gear box.  Make sure all the shims go back in the same way.

Checking with Aeromotors is a great idea.

[Vance Harral]

The actuator in your M20G should arguably be inspected in accordance with Mooney Service Bulletin M20-190B, see https://cdn2.hubspot.net/hubfs/4147179/technical_documents/service_bulletins/sbm20-190B.pdf.  While that SB does not specifically call out the ITT LA11C2115  actuator, it does call out the ITT LA11C2110, and there is no practical difference between these two ITT actuators.  The SB requires 100 hour grease intervals and 200 hour inspection intervals.  Some people argue that installing 40:1 gears per Mooney SB M20-112  should increase the inspection interval to 500 hours.  But for whatever reason, Mooney themselves have not seen fit to revise M20-190B.  Don Maxwell has some commentary on this at http://donmaxwell.com/dukes-itt-landing-gear-actuator-401-ratio-gears-si-m20-112/

If you're looking for data points about what others' do, we remove the actuator and perform the inspection of the internal gears every other annual, which is a little less than 200 hours for our partnership  We do this even though we've performed SI M20-112 to put 40:1 gears in our ITT actuator.  Any A&P can perform the inspetion.  You can do it yourself, with appropriate A&P supervision.  The chief risk in performing the inspection, IMO, is the removal and re-installation of the emergency manual gear extension cable that is necessary when removing the actuator for inspection.  The mechanism that engages this cable has to be "rigged" (positioned) correctly, and this is a somewhat delicate operation.  Too far in one direction and it will not engage when the lever in the cabin is moved to the engage position, rendering the emergency extension mechanism useless.  Too far in the other direction and the cable stays engaged even when the lever in the cabin is in the disengage position, leading to the emergency extension crank spinning when you electrically raise/lower the gear.  So whether you do the work yourself or have an A&P do it, make sure a full suite of emergency extension tests is performed after reinstalling the actuator, so as to ensure the emergency extension engagement mechanism is correctly rigged.  Every time we perform the inspection, I wonder if it's wouldn't actually be less risky to do it less often than the SB calls out, for fear of mis-rigging the emergency extension cable.  The SB is not legally binding, of course, so it's not "illegal" to do it every 3rd or 4th or 5th annual.  But for better or worse, we keep doing it every other annual.

Pay no attention to the comments in this thread about "no back" clutch springs.  Your ITT actuator has no such component, it was introduced in later model actuators.

The brushes in the actuator motor do wear out, but there is no specific prescribed interval for disassembling the motor and inspecting the brushes.  We replaced ours when our actuator failed the M20-190B inspection about 10 years ago.  We sent the actuator to LASAR who installed the 40:1 gears, and they farmed out the brush replacement to some third-party shop (I don't recall if it was George's or Aeromotors or someone else).  It just seemed like a good idea at the time, since we were effectively overhauling the actuator.

One reason I don't worry a whole lot about the brushes is, I consider failure of the electric motor to be kind of a non-event, provided the emergency extension mechanism is properly rigged.  All the bad news stories I'm aware of involving electric gear - including one in the history of our aircraft with a prior owner - involve a failure of the emergency extension mechanism after the electric motor fails.  Accordingly, we're actually a lot more paranoid about inspecting and testing the emergency extension system than we are about the motor itself.

[Guest]

I don’t know if Matt Kurke from www.comanchegear.com would do a Dukes Mooney motor, but this is what he does for Comanche motors.

Clarence