No back spring in landing gear actuators

[HopePilot]

Cardinal767 -  Did you order the part from Mooney or Lasar?

[ArtVandelay]

4 hours ago, donkaye said:

FWIW, the back spring being a single source of failure, means your gear will neither come up or go down in normal or backup mode if the spring fails.  I have replace mine every 1,000 hours until there were no more back springs made for the Plessy Gear Actuator.  The last spring for the Plessy cost $1,500 for the spring alone.  I watched Tom Rouch take the actuator apart and replace the spring.  It took him 3 hours.  I  WOULD ONLY HAVE AN EXPERIENCE PERSON DO THE REPLACEMENT.

I have a 78 J,  so I believe I have a Eaton actuator, are they equivalent, same design? Do they have same 1000 hr requirement?

[PTK]

32 minutes ago, teejayevans said:

I have a 78 J,  so I believe I have a Eaton actuator, are they equivalent, same design? Do they have same 1000 hr requirement?

My understanding is that the 1000 hour is a "recommendation." Also I wish they'd reference gear cycles rather than hours because it's diffetent for everybody. A training  airplane is going to have a lot more gear cycles in a given number of hours than one that flies longer trips.

[mooniac15u]

40 minutes ago, teejayevans said:

I have a 78 J,  so I believe I have a Eaton actuator, are they equivalent, same design? Do they have same 1000 hr requirement?

It's actually the Eaton actuators that have the problem.  http://www.mooney.com/en/sb/M20-282A.pdf

[Guest]

If we could just come up with a way of knowing when the failure will happen, we could change it on the flight before.  Until then we have two choices, change them before the gear up landing or after.

Clarence

[ArtVandelay]

So are they still making back springs for the Eaton actuator?

[M20S Driver]

1 hour ago, teejayevans said:

So are they still making back springs for the Eaton actuator?

Yes.  I just had mine replaced.

[PTK]

Is it definitely necessary to change it? Why not inspect it with a 10x magnifying glass and if looks good put it back? Is this an option?

[mooniac15u]

9 minutes ago, PTK said:

Is it definitely necessary to change it? Why not inspect it with a 10x magnifying glass and if looks good put it back? Is this an option?

The SB allows for inspection of the spring but it calls for a magnifier in the 16X to 40X range. 

[Cardinal767]

7 hours ago, HopePilot said:

Cardinal767 -  Did you order the part from Mooney or Lasar?

I ordered it from Mooney, figured they were the best source being I was told I could only order the spring as part of the SB kit. Still learning my sources. I talked to Maxwell in Longview today and I feel a little better about continuing to fly while I'm waiting on parts. I'm replacing it because I can tell the aircraft was not serviced regularly and sat for years at a time. One period was ten years.   

 

[donkaye]

54 minutes ago, PTK said:

Is it definitely necessary to change it? Why not inspect it with a 10x magnifying glass and if looks good put it back? Is this an option?

From my observation taking the gear actuator apart to inspect it takes enough time that while it is apart I think it makes sense to just go ahead and replace it.

[kortopates]

7 hours ago, HopePilot said: Cardinal767 -  Did you order the part from Mooney or Lasar?

I ordered it from Mooney, figured they were the best source being I was told I could only order the spring as part of the SB kit. Still learning my sources. I talked to Maxwell in Longview today and I feel a little better about continuing to fly while I'm waiting on parts. I'm replacing it because I can tell the aircraft was not serviced regularly and sat for years at a time. One period was ten years.   

 

I don't recall anything coming in the kit but the spring and documentation - but it's been a few years.

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[Cardinal767]

5 minutes ago, kortopates said:

I don't recall anything coming in the kit but the spring and documentation - but it's been a few years.

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The kit now comes with the instruction, the spring, some harware to replace, grease, and a new placard so each inspection can be marked on the part. Oh, and all for a low low price of $800. 

IMG_5573 (2).MOV

[PTK]

2 hours ago, donkaye said:

From my observation taking the gear actuator apart to inspect it takes enough time that while it is apart I think it makes sense to just go ahead and replace it.

I'm not so sure it makes sense to replace it. The problem I have is that there's no guarantee the new one will not break in say 30 hours. If the existing checks out fine and the gear are operating just fine I'd leave it alone. I have spoken with Don Maxwell and he feels this way.

I also spoke with Lasar and they say it must be replaced but will not sell the kit! They say send actuator to us along with 1400$ and we'll bless it!

 

 

[kortopates]

53 minutes ago, PTK said:

I'm not so sure it makes sense to replace it. The problem I have is that there's no guarantee the new one will not break in say 30 hours. If the existing checks out fine and the gear are operating just fine I'd leave it alone. I have spoken with Don Maxwell and he feels this way.

I also spoke with Lasar and they say it must be replaced but will not sell the kit! They say send actuator to us along with 1400$ and we'll bless it!

I believe Don was referring to a bad batch of springs from over a dozen years ago. I've actually gone through 3 of these because the first one had to replaced very quickly because of a manufacturing defect (I recall in the heat treatment processing) where they did have some sudden failures. A number of us had to do it twice in rapid succession because of that, but since then there have been no such issues except perhaps the doubling of the cost (or we would all be hearing about it.) For some time now reported failures have been very low as you would expect. I agree with Clarence and Don K, this is definitely a life limited part and the only life limited part called out in the Mooney Service manual. The factory doesn't make this stuff up, but they do try to come up with a time period that is going to protect 99.9% of the fleet (or so I assume). 1000 hrs is perhaps overly conservative and the factory has stated as much and that they were considering extending the time. Meanwhile after following this for many years I've personally settled on a 1500 hrs replacement schedule until there is a reliable way to judge remaining life - which most likely will never happen.

If this minor issue is the Achilles heal of the Mooney fleet we got off real lucky compared to the Cirrus in 2 ways. First the cost is nothing compared to it re-packing the Cirrus parachute. Secondly I think  there little doubt this wouldn't be legally required and listed under the Instructions for Continued Airworthiness if our Mooney's were Part 23 certified. But because we aren't, the factory's "mandatory" bulletins have no legal teeth. So owners can make their own choice. Choose wisely.

 

[M20S Driver]

3 hours ago, Cardinal767 said:

The kit now comes with the instruction, the spring, some harware to replace, grease, and a new placard so each inspection can be marked on the part. Oh, and all for a low low price of $800. 

IMG_5573 (2).MOV

You may need to plan for another $350 for the emergency extension clutch.   They are usually chewed up if the first pull during the manual extension is not a gentle one.  The one on my plane looked badly damaged and was replaced.  of course, if the emergency rope is old, it is another $250.00.

Having said that, if anyone want to fly one of the fastest and sportiest production single engines such as a Mooney, they better be ready to spend the money and not take any chances.  otherwise, fly a Cessna at much lower speeds and save money.

[PTK]

On March 17, 2016 at 5:39 PM, M20Doc said:

If we could just come up with a way of knowing when the failure will happen, we could change it on the flight before.  Until then we have two choices, change them before the gear up landing or after.

Clarence

And of course change it again after the new one just failed due to infant mortality! Because this has happened with bad springs before! That much we already "know!"

If the spring has "proven" itself way past infant mortality on a nontrainer airplane with relatively low gear cycles I just don't see the urgency to intervene and knowingly put it right back into the unknown. Is this line of thinking illogical?

Do we have basis for this such as a pandemic of spring failures or are some of us being paranoid?!

 

[mooniac15u]

7 hours ago, kortopates said:

If this minor issue is the Achilles heal of the Mooney fleet we got off real lucky compared to the Cirrus in 2 ways. First the cost is nothing compared to it re-packing the Cirrus parachute. Secondly I think  there little doubt this wouldn't be legally required and listed under the Instructions for Continued Airworthiness if our Mooney's were Part 23 certified. But because we aren't, the factory's "mandatory" bulletins have no legal teeth. So owners can make their own choice. Choose wisely.

 

"Mandatory" service bulletins aren't mandatory because we operate under Part 91. I don't think Part 23 vs CAR 3 has anything to do with it. 

[kortopates]

7 hours ago, kortopates said: If this minor issue is the Achilles heal of the Mooney fleet we got off real lucky compared to the Cirrus in 2 ways. First the cost is nothing compared to it re-packing the Cirrus parachute. Secondly I think  there little doubt this wouldn't be legally required and listed under the Instructions for Continued Airworthiness if our Mooney's were Part 23 certified. But because we aren't, the factory's "mandatory" bulletins have no legal teeth. So owners can make their own choice. Choose wisely.

 

"Mandatory" service bulletins aren't mandatory because we operate under Part 91. I don't think Part 23 vs CAR 3 has anything to do with it. 

I was referring to placing the requirement to replace the life limited part in the ICA section of the Maintenance manual (chapter 5) which would make it as Mandatory as a AD. That's what makes it mandatory on Cirrus and where they also limit the total number of airframe hours. It's not an issue for our CAR3 aircraft.

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[mooniac15u]

56 minutes ago, kortopates said:

 

"Mandatory" service bulletins aren't mandatory because we operate under Part 91. I don't think Part 23 vs CAR 3 has anything to do with it. 

I was referring to placing the requirement to replace the life limited part in the ICA section of the Maintenance manual (chapter 5) which would make it as Mandatory as a AD. That's what makes it mandatory on Cirrus and where they also limit the total number of airframe hours. It's not an issue for our CAR3 aircraft.

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You mentioned mandatory bulletins, which is the only way they can introduce this stuff after the certification process.

As far as the ICA section of the MM is concerned, it's irrelevant for any existing airframe because they can't make that stuff retroactive. If you take a look at the TCDS you will see that the later M20K's (S/N 25-2013 and up) as well as the M20S and M20TN all include 23.1529 as part of their "Certification Basis".  So, if Mooney wanted to include something like this going forward they could.

[Yooper Rocketman]

On 3/18/2016 at 10:13 PM, PTK said:

I'm not so sure it makes sense to replace it. The problem I have is that there's no guarantee the new one will not break in say 30 hours. If the existing checks out fine and the gear are operating just fine I'd leave it alone. I have spoken with Don Maxwell and he feels this way.

I also spoke with Lasar and they say it must be replaced but will not sell the kit! They say send actuator to us along with 1400$ and we'll bless it!

 

 

An interesting read below, from me and the link.  I make a living selling and fixing motorized vehicles, so have no doubt I like broken stuff coming through the door.  But I am also a realist and have seen far too many "preventative maintenance" programs cause more problems than they eliminate.  To be clear I AM NOT ADVOCATING IGNORING THIS POSSIBLE PROBLEM, just adding information from another prospective.  

In my early years, as a wrench, the trucking company I worked for, with about 60 owned trucks, 40 owner operators and 200 trailers, had a rigorous PM program. They changed out a whole list of parts based on expected mean time before failure (MTBF).  One item was an un-loader valve on a Cummins air compressor.  Back in the 70's the rebuild department sent out a "rebuilt unit" to change on a truck under the PM program, and one of my fellow techs replaced it.  The driver left later that day, got 20 miles up the road, and his air compressor quit pumping air (worked fine in the shop and for the first 20 miles).  I got the call at 7:00 PM on a cold April evening to see if I could fix it on the road.  Since the problem was beyond a road fix (at least I couldn't at my experience level at the time), I brought the driver back and helped set him up in a different truck, ironically, the "newer truck" he was supposed to get the next week, newer with power steering of which he had never driven before.  It had a few more paint touch ups and a the seat was to be changed (big guy needed a big seat) but we (dispatcher and I) decided he could get that done next week when he got back.

I get to work the next AM at my customary 4:15 AM, and the owner walks in right behind me (he never usually gets there until 7 AM).  He asked where our foreman is at and I reply he doesn't come in until 6 AM.  The owner paces the floor until 6 and then he and the shop foreman have a serious conversation and then call me over.  The owner asks me for the details of last night and then reveals the driver died that morning, at 1 AM, just after picking up his load at the tip of the U.P.  Apparently a cow has busted out of a pasture, was standing in the middle of a dark and rural road, and the driver over reacted, with the "new to him" power steering, rolling the truck into a large ditch.

I had an old Ford pickup truck at the time, with welded up metal patches covering the holes in the floor.  I will never forget heading out after work at 4:30 PM, and looking down at the cigarette butts on the passenger floor, left by the driver during the ride back to the shop the night before, and realizing as 22 year old kid that guy would be alive today had I known how to fix his truck on the road side.  

Oh, and about that rebuilt part that failed.  It was an un-loader valve cap that the governor bolted on to, and was cross drilled at a 45 degree angle from each end for the air passage, with the cross drilling extending past the meeting point of the two drilled holes.  Sand from sand blasting had accumulated in the end of the blind holes, and likely vibrated out into the air passage once driving down the bumpy road, with the engine vibrating, into the the actual valve and seized it.  The guy that rebuilt it, he had a pretty rough couple weeks afterwards too.

http://blog.aopa.org/opinionleaders/2014/01/14/the-waddington-effect/

Tom

Edited March 20, 2016 by Yooper Rocketman
Typo

[ArtVandelay]

I did a query of NTSB DB, looking for Mooneys (J or later) and keyword spring which matches locations mostly, could not find any references to landing gear problems and back spring, FWIW

[Cyril Gibb]

5 minutes ago, teejayevans said:

I did a query of NTSB DB, looking for Mooneys (J or later) and keyword spring which matches locations mostly, could not find any references to landing gear problems and back spring, FWIW

I found the same thing.  My previous post admitted that CarolAnn Garrat (sp?) had a failed infant mortality "new replacement" no-back spring.  One incident.

Although there's been posts that talk loosely about a bad batch of springs failing causing gear ups, I haven't read about another. 

We can come to end of job here with some facts.  Does anyone here know, beyond just rumours, of another no-back spring failure.  Clarence ? Don ? Anyone?

[M20S Driver]

Mooney  recommends to replace the no back spring on the new planes.  This is an extra cost that works against Mooney for selling new planes.  If this was not a safety issue.  I am sure that they would have removed it from the list of recommendations.

I know of one case of failure which happened to a friend of mine at KRHV but the wheels were down close enough make an emergency landing with no damage.  it was a J model. 

[Marauder]

On 3/18/2016 at 10:13 PM, PTK said: I'm not so sure it makes sense to replace it. The problem I have is that there's no guarantee the new one will not break in say 30 hours. If the existing checks out fine and the gear are operating just fine I'd leave it alone. I have spoken with Don Maxwell and he feels this way.

I also spoke with Lasar and they say it must be replaced but will not sell the kit! They say send actuator to us along with 1400$ and we'll bless it!

 

 

An interesting read below, from me and the link.  I make a living selling and fixing motorized vehicles, so have no doubt I like broken stuff coming through the door.  But I am also a realist and have seen far too many "preventative maintenance" programs cause more problems than they eliminate.  To be clear I AM NOT ADVOCATING IGNORING THIS POSSIBLE PROBLEM, just adding information from another prospective.  

In my early years, as a wrench, the trucking company I worked for, with about 60 owned trucks, 40 owner operators and 200 trailers, had a rigorous PM program. They changed out a whole list of parts based on expected mean time failure (MTF).  One item was an un-loader valve on a Cummins air compressor.  Back in the 70's the rebuild department sent out a "rebuilt unit" to change on a truck under the PM program, and one of my fellow techs replaced it.  The driver left later that day, got 20 miles up the road, and his air compressor quit pumping air (worked fine in the shop and for the first 20 miles).  I got the call at 7:00 PM on a cold April evening to see if I could fix it on the road.  Since the problem was beyond a road fix (at least I couldn't at my experience level at the time), I brought the driver back and helped set him up in a different truck, ironically, the "newer truck" he was supposed to get the next week, newer with power steering of which he had never driven before.  It had a few more paint touch ups and a the seat was to be changed (big guy needed a big seat) but we (dispatcher and I) decided he could get that done next week when he got back.

I get to work the next AM at my customary 4:15 AM, and the owner walks in right behind me (he never usually gets there until 7 AM).  He asked where our foreman is at and I reply he doesn't come in until 6 AM.  The owner paces the floor until 6 and then he and the shop foreman have a serious conversation and then call me over.  The owner asks me for the details of last night and then reveals the driver died that morning, at 1 AM, just after picking up his load at the tip of the U.P.  Apparently a cow has busted out of a pasture, was standing in the middle of a dark and rural road, and the driver over reacted, with the "new to him" power steering, rolling the truck into a large ditch.

I had an old Ford pickup truck at the time, with welded up metal patches covering the holes in the floor.  I will never forget heading out after work at 4:30 PM, and looking down at the cigarette butts on the passenger floor, left by the driver during the ride back to the shop the night before, and realizing as 22 year old kid that guy would be alive today had I known how to fix his truck on the road side.  

Oh, and about that rebuilt part that failed.  It was an un-loader valve cap that the governor bolted on to, and was cross drilled at a 45 degree angle from each end for the air passage, with the cross drilling extending past the meeting point of the two drilled holes.  Sand from sand blasting had accumulated in the end of the blind holes, and likely vibrated out into the air passage once driving down the bumpy road, with the engine vibrating, into the the actual valve and seized it.  The guy that rebuilt it, he had a pretty rough couple weeks afterwards too.

http://blog.aopa.org/opinionleaders/2014/01/14/the-waddington-effect/

Tom

Thanks for sharing that experience Tom. I know we all have similar events and wonder for the rest of our lives had we been better prepared or better at communicating, we could have helped avoided something bad from happening.

Same thing happens in aviation. Over the years I have met pilots who I know are an accident in the making. In the past, I kept my mouth shut. Not any more. I would rather have them never talk to me again than knowing I ignored it and to live with my decision to shut up.

Where I see this often is when I am asked to be a safety pilot for someone. If they are not flying up to PTS, I let them know.

It's tough living with a memory...

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