Nose Gear Collapse / Prop Strike Repair Estimates

[WAFI]

Well....

After flying back from St. Augustine and landing at my home airport KHWO. My front nose gear collapsed halfway down the runway and shortly after the main gear followed. The plane suffered minor belly skin damage, nose gear door scratches, bent prop, prop hub, bent crank and found the failed linkage that caused the collapse.

Given this forums experience on prop strikes and gear collapse incidents. I looking to gather any info I can on the possible cost involved with the repairs. New Prop, Hub, Crank, Tear down inspection, reassemble, New Mag, maybe governor, Landing gear assembly, etc... 

Anybody with experience with a prop strike and the overall cost to go with it, is welcome to share there experience. I would like to compare previous repair estimates or actual cost with my insurance companies repair estimate. This is my first plane, first time and hopefully last time dealing with an aircraft insurance company.

[Echo]

The insurance adjuster estimates what parts and tear down will cost. You or A&P obtain parts and install/repair. You provide receipts and claim is settled.  Should be a straight forward process. 

[Echo]

Mag?  Why mag?

[jetdriven]

The prop is  10-12 grand,  the engine is probably around 16 or more, plus the crank and any other damage. Cranks alone are 6-7k and you're lucky to find one for that.  skin repairs.... it adds up to 60-$70,000 pretty quickly.

[cliffy]

It may be an insurance total.

It can be repaired by doing the AD only on the engine crank, buying a used prop and fix the skin repairs. 
You might be able to salvage it that way 

Why new mag and governor?  Why landing gear ?

What actually broke? How did it break? Just rolling down the runway?

[PT20J]

It would be really interesting to know what broke. Do you have a picture/ part number? Perhaps your maintainer should file a Service Difficulty Report with the FAA.

At current valuations I would think it would be repairable depending of course on the agreed value of the hull insurance.

[1980Mooney]

16 hours ago, WAFI said:

Well....

After flying back from St. Augustine and landing at my home airport KHWO. My front nose gear collapsed halfway down the runway and shortly after the main gear followed. The plane suffered minor belly skin damage, nose gear door scratches, bent prop, prop hub, bent crank and found the failed linkage that caused the collapse.

Given this forums experience on prop strikes and gear collapse incidents. I looking to gather any info I can on the possible cost involved with the repairs. New Prop, Hub, Crank, Tear down inspection, reassemble, New Mag, maybe governor, Landing gear assembly, etc... 

Anybody with experience with a prop strike and the overall cost to go with it, is welcome to share there experience. I would like to compare previous repair estimates or actual cost with my insurance companies repair estimate. This is my first plane, first time and hopefully last time dealing with an aircraft insurance company.

Really sorry to hear this. This subject has been discussed before.  Unfortunately, a gear-up incident while the plane is moving on the ground is worse than a clean gear up landing with the main and nose gear fully up and retracted.  This is because of the Mooney landing gear design in which all the landing gear are linked together with push/pull tubes.  And this is in addition to the costs associated with the typical gear-up landing with sudden engine stoppage.  I will leave that for others.

In this topic on June 4, 2020 Jerry 5TJ said  "The gear pushrods get damaged in a gear collapse & that can be more damaging than a gear up. "  And Steve W said "My gear collapse, on a 1994 M20J which was probably a bit more damaging since it was in-motion ranged from about $80k from the guy who got the job and then failed at it up to $120k from a reputable MSC. No one knows what the final bill would have been because I and the insurance finally just gave up and had them send me a check."

All three landing gear are connected by push-pull rods and bell cranks to the single gear actuator.   When one landing gear moves on a Mooney (regardless of electric or manual J bar) all 3 landing gear have to move due to the linked together design.  One landing gear cannot move or collapse at a different time followed by the other two collasping unless there is mechanical physical damage to the linkages, bellcranks or push/pull rods.   And if the landing gear actuator motor is not moving (either electrically or manually using the emergency pull) then none of the landing gear can move - if they do move or collapse then there has to be damage to almost all the push/pull tubes and bellcranks.

In your case you said the nose gear collapsed followed by the mains.  If the landing gear actuator motor is not moving the only way for the nose to first collapse back and then later the main gear to collapse in is if some combination of the connecting tubes, linkages or bellcranks are bent, buckled or sheared.  It can't be just one linkage.  There are two (2) push/pull rods that push the nose gear down.  They connect to a single nose gear retraction truss and over-center linkage that holds the nose gear down.  It is possible that the single linkage to the nose gear sheared or both push/pull tubes going to the nose gear buckled causing the nose to collapse but the mains should stay locked in place if they have proper preload (explained below).   Something more must have happened to allow the mains to also collapse separately from the nose gear.  

Look at the first video.  Also look at the second video - at about 0:40 seconds he starts the manual gear extension - slowly turning the actuator - all 3 gear move together.

There are springs on the push/pull tubes that are connected to the bellcranks.  These tubes/springs are preloaded when the gear are extended. The bellcranks are over center when the gear are down.  It is the preload on the rods (tubes) that locks the over-center bellcranks which keep the landing gear from collapsing when they are fully down.  The Service Manual has a section on proper adjustment.  Chapter 32. 

mooney.free.fr/Manuels M20J/M20J/Mooney Service Manuel M20J Vol. 1 of 2.pdf

Look at the third video - at about 1:15 they show the springs and talk about how important it is to have proper preload (it is a manual gear version but the function is the same).

Look at the fourth video -  It is a M20J.  At 2:00 and 3:40 you can see the over center preload holding the main gear down.  Also at 5:00 you can see the preload locking the mains down.  Also you can see the nose gear locking down at 3:00.

The fifth and sixth video show the actuator motor in operation.  When the jack screw is extended the landing gear are up.  When the jack screw is fully retracted the landing gear are locked down.

• I would suspect that the preload was not set right on each of the landing gear allowing the bellcranks to unlock and start moving - this first allowed the nose gear to collapse back followed by the mains to collapse inward.  I think you can see,from the videos that in order for that to happen, both the front landing gear linkage has to be damaged/broken and a lot of those push/pull tubes and bellcranks for the main landing gear have to bend.  (i.e. if the landing gear actuator jack screw is not moving then something has "gotta give")
• I fear that once they open up the belly and start the estimate you will find considerable internal damage and damage to the leg assemblies.
• From Mooney Service Bulletin MB20-344 "The gear legs are constructed of welded, chrome- molybdenum, tubular steel, heat treated for greater strength and wear resistance. Main gear attaching points have bushings installed in gear mounting box attached to wing spars. The steerable nose gear mounts to the cabin tubular steel frame. -NOTE - Heat treated components should NOT be repaired; replace them."
  • The cost of all the landing gear components are high.  Each link or tube is $600-800 if even available.  The legs are much more. See Lasar 
    • Chassis — LASAR 

ADSBExchange shows your speed was good - not excessive.  You did not say that you bounced.

The question is why did this happen just now?  Did someone make an adjustment recently to any of the landing gear linkages? 

 

 

 

 

 

 

 

Edited May 27, 2023 by 1980Mooney

[Echo]

I should have said how sorry I am that this happened to you. Just a really sad event. Your hull insurance is going to be the deciding factor on whether the plane is totaled or repairable. Hope you are made whole again and back in the air soon.