M20M gear failed to retract - and failed extend (initially)

[Rick Junkin]

Sharing this morning's experience "just in case it happens to you".

This did NOT end with a gear-up landing. I have a couple of questions about some of the details of the event though. Bottom line up front - one of the links on the inside gear door for my right main became disconnected and the door didn't operate properly, preventing the right main from fully retracting.  Here's what happened:

I got a GEAR UNSAFE light, confirmed with an unsafe indication on the floor indicator, shortly after raising the gear switch on takeoff this morning. The GEAR ACTUATOR circuit breaker was also popped. I got into the checklist. I didn't know what position any of my gear were in at this point.

Question #1: Is there a checklist for this scenario? It doesn't fit the GEAR FAILS TO RETRACT - GEAR HORN DOES NOT SOUND checklist because the ACTUATOR breaker popped, not the RELAY breaker. And continuing the flight certainly wouldn't have been a good idea with the failure that I had.

After not finding what I needed in the checklist, I started troubleshooting with the goal of getting the gear indicating down and locked. I tried resetting the ACTUATOR circuit breaker with the gear handle up, and it popped immediately as expected. I put the gear handle down and reset the circuit breaker. It didn't pop, but nothing moved and the GEAR UNSAFE light remained illuminated and the floor indicator showed unsafe. So I pulled the circuit breaker.

Next step was to attempt an emergency extension using the checklist. The emergency extension clutch didn't feel like it engaged. I pulled the T handle about 40 times with no success. I stowed the T handle and the secured the emergency gear lever.

Question #2: Is it to be expected that the emergency extension clutch won't engage if the mains are out of sequence? I didn't know they were out of sequence at this time, but this could be an indication that they are, which is helpful information if you don't have a tower to fly by for a look.

I called the tower for a fly-by to look at my gear, and they cleared me for pattern entry and a low approach. Tower was able to tell me on downwind that they could see that my right main was slightly extended. I declared the emergency at that point and ran through other ideas for getting the gear down, while also considering where to land if I couldn't. I had 2 hours worth of fuel to figure it out and let the airport get prepared to clear my airplane from the runway after the gear-up landing.

Question #3: Is there any advantage to consider a belly landing in the grass vs the runway? I was going to use the runway with my gear configuration, figuring it likely that the right main would dig in on the grass and complicate things. Either way I think you get to replace the bottom of the airplane and anything else that catches.

At this point I had the ACTUATOR circuit breaker pulled, gear switch down, and the emergency extension lever stowed and latched. I put some G on the airplane while resetting the ACTUATOR circuit breaker and immediately heard the gear motor running. GEAR SAFE light and floor indication followed shortly after. I don't believe our POH suggests putting G on the airplane to help extend the gear, but its a procedure in another airplane I fly so I gave it a shot. And it worked.

I advised the tower and asked for clearance to land. It worked out ok, but in retrospect that wasn't the best decision. I should have executed the tower fly-by so that they could take a closer look and let me know if I had any damage or other weirdness. I had plenty of fuel.

Epilogue: This incident was precipitated by a fastener on a gear door connecting rod failing/coming loose. This particular door is closed on the ground and the only way to preflight the fasteners on the connecting rods is to climb under the airplane and stick your head up into the wheel well with a flashlight, not something that I have routinely done in the past. I'm going to add it to my oil change ritual, easy to do while I'm under there checking tire pressures. Incidentally, the door felt secure on my "grab test" during preflight. There was some minor deformation done to the door that looks repairable, but my IA will tell me for sure tomorrow. Either way, sure beats a gear-up landing.

Cheers,
Rick

 

 

Edited July 24, 2017 by Junkman
added pictures

[Marauder]

Sharing this morning's experience "just in case it happens to you".
This did NOT end with a gear-up landing. I have a couple of questions about some of the details of the event though. Bottom line up front - one of the links on the inside gear door for my right main became disconnected and the door didn't operate properly, preventing the right main from fully retracting.  Here's what happened:
I got a GEAR UNSAFE light, confirmed with an unsafe indication on the floor indicator, shortly after raising the gear switch on takeoff this morning. The GEAR ACTUATOR circuit breaker was also popped. I got into the checklist. I didn't know what position any of my gear were in at this point.
Question #1: Is there a checklist for this scenario? It doesn't fit the GEAR FAILS TO RETRACT - GEAR HORN DOES NOT SOUND checklist because the ACTUATOR breaker popped, not the RELAY breaker. And continuing the flight certainly wouldn't have been a good idea with the failure that I had.
After not finding what I needed in the checklist, I started troubleshooting with the goal of getting the gear indicating down and locked. I tried resetting the ACTUATOR circuit breaker with the gear handle up, and it popped immediately as expected. I put the gear handle down and reset the circuit breaker. It didn't pop, but nothing moved and the GEAR UNSAFE light remained illuminated and the floor indicator showed unsafe. So I pulled the circuit breaker.
Next step was to attempt an emergency extension using the checklist. The emergency extension clutch didn't feel like it engaged. I pulled the T handle about 40 times with no success. I stowed the T handle and the secured the emergency gear lever.
Question #2: Is it to be expected that the emergency extension clutch won't engage if the mains are out of sequence? I didn't know they were out of sequence at this time, but this could be an indication that they are, which is helpful information if you don't have a tower to fly by for a look.
I called the tower for a fly-by to look at my gear, and they cleared me for pattern entry and a low approach. Tower was able to tell me on downwind that they could see that my right main was slightly extended. I declared the emergency at that point and ran through other ideas for getting the gear down, while also considering where to land if I couldn't. I had 2 hours worth of fuel to figure it out and let the airport get prepared to clear my airplane from the runway after the gear-up landing.
Question #3: Is there any advantage to consider a belly landing in the grass vs the runway? I was going to use the runway with my gear configuration, figuring it likely that the right main would dig in on the grass and complicate things. Either way I think you get to replace the bottom of the airplane and anything else that catches.
At this point I had the ACTUATOR circuit breaker pulled, gear switch down, and the emergency extension lever stowed and latched. I put some G on the airplane while resetting the ACTUATOR circuit breaker and immediately heard the gear motor running. GEAR SAFE light and floor indication followed shortly after. I don't believe our POH suggests putting G on the airplane to help extend the gear, but its a procedure in another airplane I fly so I gave it a shot. And it worked.
I advised the tower and asked for clearance to land. It worked out ok, but in retrospect that wasn't the best decision. I should have executed the tower fly-by so that they could take a closer look and let me know if I had any damage or other weirdness. I had plenty of fuel.
Prologue: This incident was precipitated by a fastener on a gear door connecting rod failing/coming loose. This particular door is closed on the ground and the only way to preflight the fasteners on the connecting rods is to climb under the airplane and stick your head up into the wheel well with a flashlight, not something that I have routinely done in the past. I'm going to add it to my oil change ritual, easy to do while I'm under there checking tire pressures. Incidentally, the door felt secure on my "grab test" during preflight. There was some minor deformation done to the door that looks repairable, but my IA will tell me for sure tomorrow. Either way, sure beats a gear-up landing.
Cheers,
Rick
 
 

Can't answer your questions about the emergency procedures but do know that landing on the runway is a better way to belly land. Landing on dirty and grass has a potential to tear up the bottom panels.


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[carusoam]

Nice write up.  Great problem solving technique. Fantastic result!

+1 Hard, smooth surface better than the other possibilities...

Thanks for sharing...

Best regards,

-a-

[moxfox]

Glad to hear that it all worked out for you! And again thank you for sharing. We all learn from one another different experience's here.  A big thumbs Up!!

[Rick Junkin]

Lesson learned about the landing gear - If you ever have an asymmetric gear configuration caused by interference with one of the gear, something is now probably bent in the belly of the airplane. In my case its the right hand bell crank and the right hand gear extension push tube.

Tom, my mechanic, repaired the gear door linkage and we did a gear swing - the right main still would not fully retract, but the left main and the nose were fine. He dropped the belly panels and discovered that the right main push tube and bell crank were both bent. It all makes sense to me now. The single gear actuator moves all three gear symmetrically, so if that symmetry is disturbed, something has to give. When my right main bound up on retraction, the actuator continued to drive the retraction mechanism, so the push rod and the bellcrank deformed to absorb the travel that the wheel couldn't accomplish.

Straight-forward fix, now waiting on parts. I'm keeping a tally, will let y'all know what a failed cotter pin costs me...

And oh-by-the-way, yes, we replaced all of the other clevis pins and cotter pins in the gear actuation system with new. And used stainless cotter pins.

Cheers,
Rick

[Rick Junkin]

Closing this out - final cost of a failed cotter pin in this particular instance is roughly $800 in parts and labor (completed in the course of doing the annual so I'm estimating) and, a surprise to me, providing the local FSDO all of the typical ramp check documentation, including statements from both me and my mechanic, that is requested when you declare an IFE as a GA pilot. I never had to do that in my previous life or day job, which admittedly is a quite different kind of flying.

I learned quite a bit from the experience, both about my airplane and about the FAA IFE after-action process for GA pilots. I had written another two paragraphs about some rethinking I've done for how I would handle a situation like this in the future, but suffice it to say that I'm happy that it all worked out well.

I'll also add an endorsement for subscribing to the AOPA Pilot Protection Service. I called them as soon as I got the voicemail from the local FSDO, and was connected to an aviation lawyer who gave me some good advice about the call I was about to make to the FSDO. He also reviewed and edited my written statement before I submitted it. It was reassuring to have the help of someone intimately familiar with the ins and outs of the process.

Cheers,
Rick

[KSMooniac]

Thanks for follow-up! Glad you got thru it for relatively modest cost.

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[carusoam]

Thanks for sharing the fine details.

Best regards,

-a-

[Tony Armour]

Glad you figured it out and made a safe landing. I have been landing on a lot of grass lately in another airplane and like everyone said...pavement is the way to go. 

I will as I'm sure everyone will be doing....checking those rods on our doors. Props.