Help troubleshooting landing gear issue

[BaldEagle]

Finishing up owner-assisted annual which was going well until today.  Airplane is on jacks, did a couple of gear swings, all good.  But after playing with the manual extension when I try to retract the gear the Gear Actuator circuit pops.  This is what the service manual says:

 

TROUBLE: Gear will not retract & Landing Gear Actuator C/B trips.

PROBABLY CAUSE: Manual engage handle in engaged position

REMEDY: Disengage Manual System

 

The manual extension lever is latched though.  Is there a microswitch there or something?  Any ideas how I can troubleshoot this?

[Vno]

In the POH there is a warning about pulling too many times on the Emer Gear handle as it will bind up the actuator and cause it to remain engaged. I don't believe there is any electrical component or physical lock involved with the system. I'd start there. Just be sure it's safely jacked up and attempt to manually move the arm into the actuator to see if it is bound up.

Brian

[hypertech]

I did this once on jacks at the annual.  Pulled too many times and it got stuck and wouldn't retract.  The mechanic gave it a little encouragement of some kind under the belly at the actuator - I think there's a clutch or something on the there to engage the manual extension and it was stuck.  Once it got unstuck, everything has been fine since.

[BaldEagle]

I'll get the thing back on jacks and will report back.  Looks like this (hopefully) isn't going to be expensive...

[Guest]

1 hour ago, BaldEagle said:

I'll get the thing back on jacks and will report back.  Looks like this (hopefully) isn't going to be expensive...

Sometimes if the gear is overextended with the manual system the ball nut (in black) runs up against the actuator.

Clarence

[BaldEagle]

That appears to be the problem.  What’s the solution though...?

Edit: according to the service manual: “Gear may have been extended manually & ball nut is tight against stops; use wrench on ball nut flat to loosen”

[Guest]

2 hours ago, BaldEagle said:

That appears to be the problem.  What’s the solution though...?

Edit: according to the service manual: “Gear may have been extended manually & ball but is tight against stops; use wrench on ball nut flat to loosen”

I’ve never had one lock up fully.  There will be enough pressure on all of the bolts so I doubt that you’ll be able to remove the actuator and turn the ball nut.

You may be able to remove the manual extension mechanism and then turn the drive enough to relieve the pressure on the system.

Clarence

[kortopates]

So far, all the lockups that I have experienced have been because the manual clutch has not fully released after manually extending the gear. I have been successful by i) unlocking the manual extension lever to fully engage the clutch, ii) pull the handle just the least amount to get it to the side so that you re-engage the lever with the handle still exposed to pull on. next iii) pull on the handle to easily get the clutch to release - its never required a hard pull (if it does, I'd check the lever where the cable attaches too to verify is being pulled all the pack when you lock the lever full down to disengage the clutch). For this to work, you only need to be able to pull the handle while engaged just a little, but if the gear has run fully to the stop I can see not being able to get pull the handle enough to just clear the lever. But suggest trying it, because if you can get the handle clear, this should free it easily. If this does work, I also advise recommend checking the lever cable attachment at the gear for the emergency extension lever to make sure with the cockpit lever locked down that the lever at the gear pulled all the way to release the clutch.   

Like clarence, I have never seen the gear fully down to the gear box, and I am sure he has seen more than me, so that does have to be really rare. But also keep in mind when the gear is fully extended to the gear down limit switch such that the gear doen bulb comes on, that there should be a minimal clearance of about .070" between black base of the worm gear and the base of the gear housing. Check the manual for the correct spec of required clearance because the .070 is just from my memory (I think there was an actual range specified too).  But bottomline, with proper clearance it should never get that close to the gear box so that it can lock from getting that tight, so hopefully that's not your problem. That's an important check when ever adjusting the gear so the min clearance is maintained.

[BaldEagle]

Thanks Paul and everyone for the valuable feedback.  I’ll post the outcome once my A&P has taken a look later this week.

[BaldEagle]

Just in case this happens to anyone else, it's fairly simple to resolve.  My A&P just loosened the two bolts highlighted and the plate moved about a millimeter relieving enough pressure for the motor to not pop the circuit breaker.  Cycled gear a couple of times and tightened the bolts back up.