ADs Instead of Good Maintenance

The FAA has issued an AD requiring inspection of the stabilator control system of all Piper Cherokees, Lance/Saratogas, Senecas and Seminoles that are 15 years old and older. The FAA estimates that the AD applies to about 34,000 airplanes in the U.S.

What is troubling to me about this AD is that it requires an inspection that is already required by the normal maintenance rules. It looks to me like the FAA has acknowledged that many airplanes—perhaps 34,000—are not being inspected properly so a new, double requirement, is now in place.

As I’m sure you know, airworthiness directives are issued to correct an unsafe condition in a certified aircraft, including all of its important components such as engines and accessories. The AD system is in place because unexpected defects in a design, or errors in manufacturing, can occur. Often an AD addresses unexpected cracks or other failures in airframe structures. Or an AD can be issued to locate and remove components that mistakenly entered service with a defect in materials or construction.

But this new AD on a huge chunk of the Piper fleet has nothing to do with unexpected or surprising issues with the pitch control system. This AD requires a visual inspection of the entire control system from the control column all the way to the stabilator including cables, pulleys, brackets and fittings. The inspector is required to look for corrosion, cracks or wear. Duh.

Having just bailed my airplane out of its annual inspection with a surprising $6,000 tacked onto the normal bill to pay for repair of a crack in one elevator skin I have to believe all that time and money was spent on carefully inspecting everything. Wasn’t the shop and its authorized inspector required to look for corrosion, cracks and wear on all parts of the airframe? Isn’t the pitch control system pretty important and something that should be looked at closely while all those inspection hatches and interior components are removed? The answer is yes.

In fairness, the AD on the Pipers requires that the control cable turnbuckles be unscrewed for a complete look at the components, and that wouldn’t be a typical inspection procedure. But if a careful inspector saw the beginnings of suspected corrosion or fraying of the cable on or near a turnbuckle he would certainly take it apart for a closer look in any case.

There have been two accidents and one incident involving failure of the pitch control system in Pipers covered by the AD. The NTSB has been pressuring the FAA to do something to prevent additional accidents. Fine. That’s the NTSB’s job. But does a new rule—the AD—force inspectors to do what they were already required to do?

Light piston airplanes such as the Pipers covered by this AD are certified under the concept that regular inspections will find and fix problems before they threaten the integrity of the airplane. So, it was determined during certification that there is enough margin in the Piper’s pitch control system that small cracks, the beginning of corrosion, or wear will be found during annual or 100 hour inspections and repaired before leading to actual failure. Regular inspection is the foundation of certification.

Larger airplanes are certified under fail safe and damage tolerance concepts. That means in a transport airplane the wing spar, for example, must have multiple elements that can carry the design loads if one of the elements cracks through or in some other way fails. Inspections are still important for transport airplanes, but there are structural backups in case something breaks between inspections.

The FAA goes even further for transport airplanes and all twin turbine airplanes by requiring an approved maintenance plan. Those approved procedures demand very specific inspections including required overhaul or replacement times for critical components.

So far the inspect and repair concept has worked well for the piston fleet. In my case, the crack in the elevator skin was about six inches long and it was impossible to know how long the crack had been there. But the crack was discovered, as it should have been, during a normal inspection, it was fixed, and airworthiness was not threatened.

The new AD on the Pipers looks like a first step toward applying the required approved maintenance procedures for turbines to piston airplanes. Now inspectors will have to not only examine the pitch control system, as they have been required to all along, but they will also need to record in the permanent airplane records that the inspection was performed. If nothing else, just the paperwork of researching the AD and recording that it has been complied with adds to the cost of what should be normal maintenance.

With this AD the FAA has signaled that is has lost confidence in the normal required inspection system for light airplanes, or that it is taking early steps to develop required maintenance procedures for all airplanes. Either way, it’s not a good situation. By the FAA’s estimate owners of the Piper fleet affected will spend more than $14 million to comply. And airplane owners who had been paying for complete and valid inspections as already required will share in the bill along with those who cut corners on maintenance. Actually, the corner cutters will probably ignore the AD just as they have skipped over other inspection requirements so only the careful airplane owner foots the bill.

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24 Responses to ADs Instead of Good Maintenance

  1. Cary Alburn says:

    Annuals are pretty labor intensive, and it’s easy to see how unexpected interruptions, etc., can interfere with the methodical checking of every single item. Almost any competent IA who looks at an airplane for the first annual after purchase is likely to find many things that the last several IAs overlooked. That doesn’t mean that previous IAs were incompetent, just that a fresh look often discloses what previous inspections overlooked. I’m not a mechanic, but every time I visit my IA’s shop while he’s doing an annual, I’m amazed at what has to be done, and that he finds things that are really hard to see.

    If I owned one of the affected Pipers, I might be irritated at the AD. On the other hand, I’d rather be irritated than to have a cable suddenly come loose while I was in the middle of a tight approach into a smallish airstrip, just because a series of good, competent IAs might have missed a problem that would have been addressed by the AD. It’ll be interesting to see if over the next year the list of repairs caused by complying with this AD made it worth publishing it.

    Cary

  2. Kayak Jack says:

    A LONELY ZERK
    After 15 years of experience in aircraft maintenance in the Air Force, I know that human nature is designed for us to make mistakes. That’s one of the reasons for training and checklists.

    When I first became a student pilot, I rented from a Cessna Flight Training Center. I came to recognize that the owner is sleazy, and I didn’t trust him much. So, I took my own sweet time with preflights. One day, I was preflighting a Skyhawk that had just landed, being freshly returned from a 100 hour inspection. A Zerk on the nose gear scissors still had old, dirty grease on it. No one had wiped it clean, pumped in fresh grease, and rewiped the Zerk. When I pointed this out to the owner, and told him that if something THAT simple had been overlooked, what else was missed also? He shrugged, and walked away. Did I mention that he was sleazy?

    I’m pretty sure the extra $6,000 you paid included a LOT more than repairing a 6″ crack. If not, there will be a lot of FBOs near KMKG standing in line to fix your bird. ;=))

    If a turnbuckle is cracked open, the system will have to be rerigged. That will add another bundle to the repair bill.

    Now, a question. If a mechanic does the AD and finds clear evidence of a problem, will action be initiated against the last mechanic who overlooked that inspection checklist item? What is FAA’s history on this kind of a situation? I don’t know, so am inquiring.

  3. Pete says:

    This sort of basic unfairness is built into the very foundation of the government. Guns are regulated, taxed? Law-abiding citizens pay the bill, criminals continue as before. Same with everything: welfare, arts and sciences, home appliances and houses, immigration, schools. This is the cost of having the governance at all. The problem occurs when the system is overwhelmend with unfairness and every actor goes rogue. Fortunately in case of avitaion, government is well on its way of destroying it altogether, so it’s not going to happen. BTW, expect more stiff anti-experimental and anti-ultralight penalties in the future. These types of aircraft provide an opportunity to escape the iron grasp by slipping past its fingers and is not going to be tolerated. Is EAA ready?

  4. Jake says:

    Let’s give the FAA some credit. At least they didn’t require REPLACEMENT of good components.

    As a Robinson Helicopter owner, I can tell you that it could be a LOT worse. In the last decade, the FAA has required owners to pay for several factory design and quality control errors, often to the tune of tens of thousands of dollars a pop.

  5. bdk says:

    Does Piper issue service bulletins on this sort of thing?

    If this is normal wear that most any IA should find using a reasonable standard of care, I’m with you. If this is damage or wear in hidden areas, then the AD seems just to me. A mitigating factor is the fact that this is part of the primary control system. A cracked elevator skin, which should be fairly easy to detect, would have to grow quite large to make your plane fall out of the sky. Not so with a failed control cable connection.

    I’ve seen plenty of airframe cracks that wouldn’t concern me. Stop drill them and move on. I would have a different standard for an elevator hinge bracket though.

    I’m a big fan of government conspiracy theories, and I’m not a big fan of the FAA bureaucracy, but I don’t have enough info yet to form an opinion. Maybe Piper even went to the FAA and requested this action?

  6. Richard says:

    Thorough inspection of control system components should be a part of every annual, especially of older aircraft. Cables, pulleys, brackets etc are wear items. Having owned several ageing airplanes, it seems there is an issue with some part of the control system on every annual.

    There has been at least one “mandatory” service bulletin and several reminders from Piper in the last two or three years. Of course unless the aircraft is in commercial service, “mandatory” is meaningless.

  7. Bill Berson says:

    Greasing a nose strut scissors is not part of a 100 hr inspection.
    Service and lubrication is not inspection. Some can be done together, but not always.
    Cessna recommends the scissor should be greased every 50 hours, but this is not mandatory.
    So if the strut was lubed 20 hours before a 100 hr inspection, it does not need it again.
    However, Part 43 Appendix D does require that before an inspection the aircraft shall be thoroughly cleaned.
    (Whatever thoroughly clean means).
    I agree with Mac, I think. When the rules are too complex, they may be ignored.

  8. John Clarke says:

    Re elevators, can tell you $6k not too bad, try doing baron magnesium repairs!!!

    • Mac says:

      Hi John,
      My airplane is a Baron and the elevators are magnesium. The best solution is to exchange the elevator to SRS Aviation in Minnesota. SRS has an STC to re-skin the elevator in aluminum instead of magnesium. You can do one elevator at a time, no need to match aluminum and mag on both sides. The cost is around $5,000 plus shipping and painting, but the problems of corrosion and cracking that are so common with mag are gone. SRS provides aluminum parts to several experienced shops that re-skin Beech flight controls, but not sure if they ship internationally. Check out srsaviation.com for more info.
      Mac Mc

  9. SkyGuy says:

    To properly inspect any cable run requires disconnecting at least one end and pulling the entire cable out for correct inspection.

    Then the cable (if good) has to be re-routed back.

    I have seen cables that would not pass the reverse bent insection.

    Finally…..the entire aircraft must be re-rigged and test flown….and adjusted if needed.

    Sounds like us A&P’s just got a raise.

  10. Josh Johnson says:

    I’m afraid I’m with skyguy on this one – too easy to have undetected internal corrosion on these cables. Piper’s big ole counterweight bouncing around in there might be an issue as well.

    Issue #2 is the unscruptuous mechanic – the last couple big annuals I’ve done represented all out neglect – such things as not ony worn out, but cracked wheel bearing cups, mis adjusted landing gear, improper installation of exhaust ball joint with resulting exhaust leak, worn out flight control components, ad’s not complied with, etc, etc, etc.

    I kind of chuckle when someone tells me they just paid $300 to get their Cherokee annualled. This almost with certainty will include the following: Mechanic is uninsured. All preventive maintenance & servicing is your responsibility. Mechanic does not use any sort of checklist. If you’re lucky, maybe you got a compression check and oil change, but probably not. Such guys famously repeat the lines “well, it only flew 50 hours last year” and “everybody knows we cause more damage doing an annual than leaving well enough alone!”

    Gee, I think I’m ranting now – sorry!

  11. Chris says:

    To BDK re: “Does Piper issue service bulletins on this sort of thing?”

    Piper did issue an SB on exactly this issue. The AD cites it in a “what Piper said? Do that,” manner.

  12. Charlie says:

    I’m afraid this type of AD will be more and more common. Look at how many repetitive Lycoming AD’s are out there. Not recurring but just reissued because they were not being done. I’m an IA and run a small shop. I keep a file of photos showing the scary things that have come in the door over the years. It’s pretty thick. One 172 wing failed sitting on the ramp when we opened the tank cover. The other problem is about 1/2 of the overhauled and new components I get have some defect or problem. Quality control stinks. I’m talking about big ticket items like radios, engines, instruments. The time to trouble shoot the failure and convince the overhauler it’s defective is terrible. Used to be the airplanes that were never annualed and owner kept flying them were the bad ones. Now they are a mess coming from a regular shop. I’m afraid this is the first of many AD’s to come on all makes. Every type is getting hit with at least one “big” AD. Ask the Comanche owners too. And the AD’s address problem areas so it’s not unneeded. Just the AD is not always written by someone who knows the airplane. Other times the AD is resisted even though there is a bigger problem. I’ve found 14- 16 cracked wood Aeronca spars, (sorry lost count) and the type club wasn’t interested when I argued maybe the spar AD was needed. Some were previously replaced and damaged beyond repair on installation. So the AD’s may cause more harm than good. The Comanche stabilator AD is a similar example. Very close tolerance critical parts being disassembled and reassembled without proper tooling. For the Cherokee AD how many will be rigged right on reassembly? How many have corrosion on the steel fittings under the cabin door against the skin where it’s not visible? Might be the next AD. Take a look sometime.

    • Bill says:

      Charlie, I agree with you on the rigging. Having rigged many Cherokee series, I wonder how many people doing it will either try to find the proper rig tool or make one per the Piper Service Manual, took me a day to make mine years ago, or will not follow the instructions to level the aircraft properly. You would be suprised how many mechanics don t know the purpose of those two screws sticking out of the left side of the plane.

      • Charlie says:

        Exactly. the cherokee has no fixed stabilizer to line up with for neutral. Same applies for getting cables back in pulleys, setting proper tension, cottor pins in critical areas, safety turnbuckles, etc.
        The sad scenario I see are airplanes left to rot at the coast and then scooped up in a back tiedown lein sale. Sold with new paint and interior to dress them up but they are still a mess inside. E-bay airplane buyers sees low time and new paint/interior. Flies it a year and then comes in for first annual. The IA is left with a mess and trying to fix every squawk is tough. The AD list is nonexistent and even if there is one it’s wrong.
        The airplanes cared for and maintained, kept in hangars still get the same AD but how can you make a line to say airplane A needs the AD and airplane B does not. No good answer. The other problem is the mechanic ahead of you was probably a nut so when the airplane comes into the shop for first time all AD’s need to be researched and done again or at least visually inspected. not a FAA rule but my rules. Back to the beginning because I’ve been burned so many times.
        So this AD being done in the logs is no indicator of it being done correctly. Next trouble is how many mechanics part 91 have current Piper SB subscriptions. The FAA should print the AD to mirror the Piper SB! Will Piper provide a current copy of the SB for free or at least a website download? Or you can head to Kansas city to view the FAA copy like the AD says.
        How many part 91 operators have the CURRENT Piper MX manual and parts manual too. IF you inspect per 43 appendix D checklist are they required?
        The AD could at least list the current info and specs to put the airplane back together. Also show hot spots where the failures have been found. Too many lawyers and not enough focus on simple wording to find a problem with clear photos or diagrams.

  13. Gordon says:

    Hold on a second here , Pete…

    It’s easy to scream “Government Overreach” at every turn…

    sometimes it is even true…however in the case of Airworthiness Directives…it is more a case of having a whole organization that is focused on making sure the airplane YOU fly is up to snuff…

    What’s wrong with that…?…look it is a very long list of defects that have required ADs to fix…how come nobody is mad at Piper or Cessna or whomever built the airplane for cutting corners…?

    I think Mac is making an issue out of nothing here…first of all there have been some accidents….the NTSb has weighed in and raised a flag…it is now the FAA’s job to make sure these issues are addressed…

    I think Mac’s criticism of this FAA move would hold more water if he provided some context about those crashes and the NTSb conclusions…

    That is one of the benefits you get when you buy a certified airplane…there is a system in place that continues to monitor your aircraft and make sure the type continues to be airworthy…

    Yes…this particular directive seems to underline a maintenance issue that should be part of the annual inspection…well it seems that crashes have happened so maybe this item is not being looked at properly…

  14. Bill Berson says:

    I recall several Beavers that crashed shortly after an AD was issued.
    While doing the AD compliance, mechanics got the aileron cables reversed. The AD medicine may have been worse than the disease, in that case.

  15. Stephen says:

    The FAA and the NTSB are not always in tune or correct on their findings and conclusions on accident statistics. Take the case of N295BA (Helio Super Courier) of Branham Adventures that perished very near Wolf River Lodge, AK. They sent out a service bulletin to all Helio owners and to Helio Aircraft LLC. The cause was determined to be a corrosive issue in the lower attachment fittings in the wing carry-thru, and that failed. No it did not. It was a medical issue with the pilot who had high blood pressure and sleep apnea. Branham offered to help with the examination and the AK office refused. I’m not saying the AD is not warranted at some point, but there should always be a wing pull of airplanes 25 years and older on the 1500 hour mark if it’s not been done. The PA-28, 32, 32R, and all the rest have the flying stab, so does the Helio. The stabilator on the PA-28 is far easier to work on and inspect, but can be time consuming. This should be a service bulletin, and not an AD..

  16. Jay says:

    What happened to my comment?

  17. Pingback: AD for many Piper aircraft « Ad Inexplorata

  18. Josh Johnson says:

    Bill – regarding the ailerons being reversed, I really think there should be a basic level of flight training required for an A&P. Maybe not a whole private certificate, but at least 20 hours of dual or something like that. That said, it’s sure a good reason to check your flight controls are free and correct, especially after doing maintenance.

    Personally, I think I’d have a real difficult time doing my job without the ability to go test-fly my work. It’s amazing how many little things I find when doing a test flight after completing an annual – I’d say I end up tweaking some little thing here or there on about half the planes I work on, and my customers seem to be real happy with the results.

  19. Bill Berson says:

    Josh- I watched one of the Beavers that crashed after reversed ailerons. That image is burned in my memory. In that case, the mechanic was also the pilot/owner (with 9 thousand flight hours).
    Every flight after maintenance is a test flight. The pilot should double check everything as much as possible.

  20. SkyGuy says:

    Dosen’t the pilot check for full & correct defection of control sufraces…prior to fight.

    The airline guys try to do this.

    Shame on GA the pilot.

  21. David says:

    dissimilar metal corrosion is a design issue and hidden damage on a primary flight control requires additional measures

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