***Mon 02 NOV 2020 update***
U.S. FAA AD 2020-21-22 adopted, effective 07 DEC 2020:
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/c8c585a037fe19ee862586140053ce37/$FILE/2020-21-22.pdf

Previous Posting:
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Details at

https://www.federalregister.gov/documents/2020/05/14/2020-10316/airworthiness-directives-textron-aviation-inc-airplanes

Textron Aviation Single Engine Mandatory Service Letter SEL-55-01 is referenced.

Suspect above will result in a few aircraft removed from the register due to "beyond econmomic repair", even if Cessna makes a special production run of scarce parts...

It only takes 2 hrs to do this inspection? I thought most people were saying the the horizontal needs to come off to see things properly?

I can’t determine when this would be do....did I miss something

"Within the next 100 hours time-in-service (TIS) after the effective date of this AD or within the next 12 months after the effective date of this AD, whichever occurs later, and thereafter every 500 hours TIS or 5 years"

I performed this inspection when the service letter came out. My IA had been wanting to do this anyways because as far as we knew the tail had not come off for a lot of years and he wanted to check everything out and also rebuild the trim mechanisms.

Yes we had to remove both the vertical and horizontal tail surfaces.

Good thing he did because here is how my stabilizer trim hinge bracket looked:

It is unclear to me if having previously complied with SEL 55-01 constitutes compliance with the proposed AD. The proposed AD requires the additional step of inspecting for loose or sheared rivets. Any competent mechanic would do that while complying with the Service Letter but if it isn't documented, it didn't happen.

SEL 55-01 also isn't listed in the list of documents referenced in paragraph (h) Credit for Previous Actions.

Opinions?

I basically did this inspection about 20 years ago in a round about way. I disconnected the elevator control rod from the bellcrank and then removed the hinge bolts and lifted the rear of the stabilizer up until it made contact with the bottom of the verticle fin. I had the jack screws extended to the max. The reason I did this was to replace the steel bushings that the cast aluminum hinges pivot on. My early 180 doesn't have any plastic parts back there. Just a steel bushing with the bolt holding them between the hockey stick and the inner bracket in the tailcone. It was easy to inspect the hockey stick for cracks with a mirror too.

I and several others have detailed the SEL-55-01 process here:

https://backcountrypilot.org/forum/cess ... t=sel%2055

There’s no way the inspection could be done in 2 hours, unless a borescope is used. In fact, the labor/parts breakdown has a separate line item for remove and reinstall stabilizers/rig flight controls. The Feds say 8 hours to do that. I would estimate it would take me 6-8 hours for horiz/vert stabilizer takedown and another 6-8 for reassembly, plus a another couple hours assistance with another pair of hands. Not to mention another 1/2 hour for for logbook entries and updating the AD list.

The most expensive part I replaced, 0712048-7, is now $5802; undrilled. Drilled, $2230. When I replaced mine, I tried a salvage one, but the drill pattern didn’t match well enough. I guess the good news is that part was $7K in 2018, so they’re a little less hideously expensive now.

There is this approved repair to the hockey stick: https://www.cessnarepairs.com/?gclid=Cj ... wDEALw_wcB

These guys are poised to clean up with it turning into an AD

The fix for any issues is here... https://www.cessnarepairs.com/
A lot cheaper than the factory parts...

I have done this inspection several times by removing the rear hinge bolts, disconnect the rudder cables and elevator then jack the horizontal up as far as possible.. Using a good light, mirror and video boroscope I can get a good look inside everything that's in there... Takes a maximum of a couple hours to do, if even that long...

Now if they release an AD that requires the removal of the vertical and horizontal to inspect I will do that for future inspections, however, I do not see it taking longer than 3-4 hours.. With a couple of guys the vertical and rudder can come off in one piece with half a dozen bolts and a few wires. Elevators come off real quick with the right tools and the horizontal is 4 bolts.. Takes about 45 minutes to an hour to remove all of it.. inspect and put back together replacing any worn parts along the way..

Brian

Brian-StevesAircraft wrote:I have done this inspection several times by removing the rear hinge bolts, disconnect the rudder cables and elevator then jack the horizontal up as far as possible.. Using a good light, mirror and video boroscope I can get a good look inside everything that's in there... Takes a maximum of a couple hours to do, if even that long...
Brian

^^^ This

jrc111 wrote:I and several others have detailed the SEL-55-01 process here:

https://backcountrypilot.org/forum/cess ... t=sel%2055

There’s no way the inspection could be done in 2 hours, unless a borescope is used. .

That was an awesome thread! Thanks to you and the others in it for documenting this work.

Ross

kg wrote:It is unclear to me if having previously complied with SEL 55-01 constitutes compliance with the proposed AD. The proposed AD requires the additional step of inspecting for loose or sheared rivets. Any competent mechanic would do that while complying with the Service Letter but if it isn't documented, it didn't happen.

SEL 55-01 also isn't listed in the list of documents referenced in paragraph (h) Credit for Previous Actions.

Opinions?

The AD when it arrives will have an affective date, IMO you can’t sign of an AD by referencing a service letter inspection you did prior to the effective date of the AD. Unless you can somehow verify and document that there has been no time in service since you did the inspection. Even that might be a little murky as corrosion can happen with the thing sitting on the ramp.

Might seem like some pretty silly semantics but that’s all bread and butter for feds looking to violate an A&P mechanic for falsifying records.

Opinions?

I’m having some work done in the next month, and was planning to do the MSB at the same time. Am I reading correctly that it would be wise to await the AD?

Beegles charged me $1000 to comply with the SEL so either I got screwed or the FAA's $175 estimate is way off.

StuBob wrote:I’m having some work done in the next month, and was planning to do the MSB at the same time. Am I reading correctly that it would be wise to await the AD?

I've been putting off doing the SL inspection.
I will now be putting it off a while longer while I wait for the AD to actually be issued.

If you read paragraph (h) of the proposed AD, it appears to me that if you performed the detailed cleaning, corrosion removal, inspection and replacement of any parts with cracks by following the SB and the applicable service manual within the past 5 years or 500 hours, then you’re good. No need to wait for the final AD. However, the time of that inspection also starts the clock for the next follow-up inspection after another 5 years or 500 hours. If anybody has a different interpretation of this, please jump in.

Ross

It’s amazing to me that the tail even stays on a 180-185. Take a look over your shoulder sometime when you do a run up. They must be Hell for stout. I can see where the years/hours add up and are hard on them. Yes expensive and inconvenient but probably makes sense to take a look in there. Glad I don’t have one though[emoji1]

It's probably worth inspecting every 10-20 years. My issue is the time between inspections. This is a big job and you need to strip paint to properly inspect.

The way we perform damage tolerance analysis and how inspection intervals are typical set are through DT and crack growth analysis. In the FAA world we grow a crack using a load spectrum from critical fasteners assuming there was one there during production. We continually check the residual strength of the structure with the crack until it grows large enough to shows zero residual strength. Then we take the amount of time it took to grow the crack, divide it in half and that's the inspection interval.

Now what's better than analysis is statsical data over time. Has there ever been an in flight structural failure of a tail? My guess no. That means the youngest airplanes have been flying with adequate residual strength for 40 years. The oldest for 67. Assuming the above logic and being ultra conservative the tail should be inspected every 20 years. We also define inspection methods (visual vs various ndi) based on the size of the crack that would cause zero residual strength.

I think the tail inspection is worth doing but every 5 years is wrong. Either the FAA published the proposal at 5 year intervals to look like they are being reasonable when they "compromise" to 10 year intervals or some engineer at the FAA pulled 5 years out of thin air. It doesn't line up with their aircraft certification regs.

Interesting stuff, and I appreciate the education. Could you please submit these comments to the decision makers?