Upside Down Trim Tabs Cited In Fatal Navajo Crash


The NTSB says improperly installed trim tabs were a factor in the crash of a Piper Navajo in Myrtle Beach last May 21. A preliminary report (ERA21FA224) issued this week said investigators found the trim tabs were installed upside down and backward during an annual inspection completed two days before the flight. All the control surfaces had been removed and repainted during the annual. The flight was a post-maintenance hop from Myrtle Beach International Airport to Grand Strand Airport in North Myrtle Beach. The aircraft crashed in a field and was consumed by a post-crash fire. The tanks were filled with 167.5 gallons of 100 LL before the flight.

The pilot, who was an ATP reportedly working for American Airlines, took off and almost immediately told ATC he needed to return to the airport. About a minute after takeoff the controller asked if he needed help and the pilot replied “yes, we’re in trouble here.” While turning for the downwind the aircraft reached 1,000 feet AGL, dropped to 475 feet, climbed to 700 feet and then dropped from radar at 450 feet. 

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. Another tragic case of maintenance induced failure. My condolences to the family. A similar case happened years ago to the Beech Sierra/Sundowner family of aircraft. A pilot crashed his Sundowner after the ailerons had been installed in the opposite wing following painting and balancing. The FAA issued an AD requiring owners to install a bracket in the wing preventing the push rod to the aileron from attaching if the wrong aileron was installed. I suspect a similar action may be in the offing here.

    • John Mc: Thanks for the info.

      I couldn’t find the Beech Sierra/Sundowner AD, so I’d appreciate if somebody could post a link.

      • There is a Service Instruction that appears to be what John is referencing. I can’t find a web page that shows the text of the SI.


    • We all due control deflection checks prior to take off, point the horns at the up control, in other words turn the wheel left and left aileron goes up, right and right goes up. Pull and the elevator goes up, rudder back and forth. How many check the flaps, slats, and trim? Perhaps you say continued check of those wear them out. Your test will be when they are set for take off. How about extending one notch beyond take off then retracting and checking, then again with trim, roll it right and look at the tap, roll it left and look at the tab. then center it again. This should especially be done when coming out of maintenance where paint or control surfaces have been removed. Every moveable surface should be exercised and checked for expected for proper movement. Once in the air its way too late.
      Now if you are in the air and you move a control which aggravates the issue, put it back where it was and if it helps think reverse and try it in the opposite direction to see if that helps. Continue to fly the airplane and adjust power to control the problem. Here is a situation that you want a steady airspeed not accelerated airspeed. Keep conditions constant so you can work out the problem. Return to land ASAP, and if things are getting too bad, put it down right side up and get out alive. Then call the insurance company to report you need a new airplane, instead of being dug out of a smoking hole. Even with ME airplanes I tell my students that if you start to lose the airplane or get a roll started, reduce power, get the nose down and if you have altitude add power slowly to increase airspeed. If the ground it too close, pick a spot and put it back on the off airport ground where you can get out and call your insurance company instead of your widow. Land under control, as all airplanes are gliders with the engines at no thrust.

  2. Every plane that I knew going through maintenance involving removal of control surfaces or cables, I would always do a control surface check before flying to make sure this kind of accident doesn’t happen to me. Condolences to those involved.

  3. In Europe under EASA Legislation, a lot of the maintenance tasks and areas are deemed as “critical”, like fuel system, control system, engine controls etc.
    If any work is beeing performed on these, there must be a 4-eye double-inspection performed and signed off to prevent these kinds of failures. No matter if it is small or big aircraft, private or commercial operations.
    This tragic accident and death has been 100% preventable.
    Very sad, my condolences.

  4. Whatever happened to “free and correct” during the preflight? I always check my trim as part of that activity. Not too hard to do at all. Sorry somebody had to pay the ultimate price, though.

    • “Free and correct”, yes, every time. But frankly I’ve never thought to check the trim regularly. Curious how you do that, sitting in the pilot seat. Running it back and forth doesn’t check the tabs for correct movement.

      • I always set mine for take off after landing. During my preflight inspection I note where they are are in relationship to the ruddervator.

      • I’m with you. For 50 something years I’ve always checked free and correct before every flight. However, until this accident, the trim tab has never occurred to me, not to mention how do you do that from the cockpit. We learn from accidents. After an annual the trim tab movement will be something to check now.

        • Open the door and look back while trimming and you will see a steady held elevator with the tab in back rise and fall as you roll the trim.

          • That works for some small aircraft but not on larger planes or jets. In those instances the only way to check movement takes two persons, one to move the controls, the other to watch from outside. Some larger aircraft have markings on the outside of the horizontal stabilizer so to be able to verify elevator trim control settings. If you get a ramp check by an inspector who actually knows what to look for on that aircraft, you could get grounded if those markings are no longer visible.

          • Can’t do that from the pilot’s seat in a Cherokee. Heck, you can’t even see the rudder. But, if my plane just had control surfaces installed, I’d do whatever it takes to make sure they were correct before taking off.

    • We should start talking about the technician shortage combined with extreme demand on existing shops. Big shops and little shops are having the same quality issues. Many of the issues are potentially fatal as with the sad Navajo story above. I was a Captain for one of the largest 135 operators in the country. The company through a massive (absurd) amount of money at maintenance trying to do it right. Didn’t work. Many of my work-cycle tours began picking up aircraft following maintenance at brand-name shops. Many were not airworthy following maintenance. But, by God, the paper work was correct…..

      In the next decade the problem of bad maintenance will escalate. We simply can not tool up fast enough to meet the demands and the retirements.

      • Jeff, I believe that you hit the nail on the head. We have a big gap in our AMT cadre right now. We need more new blood, and a lot of the older AMTs want to do the bare minimum. Shops are backed up, the level of maintenance has dropped.

  5. A return-to-service preflight inspection can help prevent these types of post-maintenance accidents. My type club, MMOPA, has published such an inspection routine for when aircraft come out of annual or significant maintenance. Removal or repair of control surfaces is a significant maintenance event. Years ago, a shop repaired an aileron on my PA46 Mirage that they had damaged. The repair looked perfect. But in my post maintenance test flight, it was all I could do to keep the plane from banking hard left. Turns out that without a jig, that aileron cannot be re-skinned properly, so had to be replaced with new. Had that test flight been with full fuel and plane loaded with passengers, might not have made it back to land. Assume nothing post maintenance.

  6. After my plane was painted we moved the controls, moved the trim tabs. Made sure they were centered and so on. Not sure why this plane crashed. He was in the air for some time, enough to figure out the trim tabs were working backwards. Something else must have been going on.

  7. Terrible tragedy, my condolences to all involved. I am not familiar with the Navajo and was wondering if someone could give a brief explanation of “upside down and backwards” as it applies to this trim tab? Did the tab move opposite during actuation or not work at all, and was it set to takeoff position prior to takeoff or was that not able to be determined? I will look for the NTSB report. Thanks.

    • Jerry M – YOU took the words out of MY mouth!!
      Why didn’t anyone come up with the answers to those questions???
      Also – If nose up trim was selected & the response was nose down, I would try nose down & see what happens. No brainer.
      My take

  8. A lock nut on a pitch control rod loosened on a training helicopter, oozing linseed oil during a preflight. This wasn’t on the checklist but something I did, a hands on approach. When I asked one of the instructors, they all came out and spent the next hour or so contemplating, called the school owner who is also an amt, tightened the lock nut, wiped off the sticky oil before letting me take off solo on a brief practice around the airport and area. I knew the pitch control rod wasn’t going anywhere because the opposite end has its own lock nut, preventing the rod from unscrewing and altering the dimensions but an abundance of caution prevented this newbie from flying until all the commotion was in agreement and within procedures. All preflights become mundane due to repetition but complacency wasn’t and shouldn’t. This preflight stands out along with mistakes I can talk about as a reminder against complacency.

  9. I’ve seen incorrect trim tab installations twice in my flying years. My Baron had a new elevator installed by Ratheon no less, and on delivery my pre-flight found the trim tab operating perfectly, backwards. Many years later I went with my student to pick up his 182 after an autopilot installation and found the same issue. Checking proper elevator trim tab operation in most planes requires you to walk back to the elevator. I don’t think it’s necessary for every flight but certainly if maintenance gets anywhere close to the tab control system a one time post maintenance check is advisable.

  10. Never, never, never accept an aircraft post-maintenance or post-annual without going through it thoroughly. Ask me how I know.

    A couple of years ago, during a general re-do of the instrument panel in my ’73 Aztec, unbeknownst to me the new JPI engine monitor was connected to the wrong engine(s), which is to say the CHT and EGT wires for the left engine were connected to the right monitor and vice-versa. In a hurry to get the airplane out of the path of an oncoming hurricane, I didn’t do a thorough inspection before accepting it and flying it home. My bad.

    Later, at the home ‘drome, when my instructor and I were doing maneuvers, I inadvertently put the right engine into the “red box.” Via my new engine monitor I recognized the problem immediately, but because all the other sensors besides the CHT and EGT were on the correct engines, the oil temperatures were correct, as well as the readings from the native Piper instruments. It was totally confusing. We could never figure it out, and – long story short – I continued to reduce power on the wrong engine, richened the mixture on the wrong engine, added power to the wrong engine to compensate. Had my grizzled instructor not been on board, I would have shut down and feathered the wrong engine.

    Fortunately, we were close to the airport, and reducing power on both engines during the letdown prevented engine stoppage, although several of the CHTs were in the seven-hundreds.

    A quick check of compressions identified the “bad” engine – and the erroneous installation. When I bounced the repair station about the error, the owner’s comment was, “It’s your fault – you should have known the sensors were wrong.” Yes, maybe one. Maybe two. Maybe even three. But not 24. Although there was aluminum on the spark plugs, there was none below the pistons, so I ended up with “only” a complete top overhaul, which the installer refused to even help pay for. I don’t sue people, but he and his shop are locally famous, and getting more so.

    Epilogue: We lived to tell the tale. I later observed my same instructor, who is a commercial pilot in real life, spend almost an hour in the southern summer sun, inspecting and verifying free and correct movement of all control surfaces and trim tabs after an extensive maintenance session. Lesson learned.

  11. I have always believed, sometimes with justification, that when it comes to risk, the first post-maintenance flight is right up there with an approach to minimums (or worse) to a new airport in nasty weather. I have experienced profound wing heaviness from an only slightly-bent fixed trim tab (requiring a major yoke deflection to remain straight and level), no control over a constant speed prop (unsecured crimp nut on a control arm, leaking hydraulic lines that were torqued almost tight enough. And this after I went through the airplane closely on preflight. How much more bent was that fixed trim tab, anyway? A lot, as it turned out. As for the others, I could have gone over every fastener with a torque wrench and not by hand, but at some point you have to just fly the damned thing.
    But one warning I always gave every shop: any tool, anything they leave in the airplane becomes mine. As a result, after a reasonably long flying career punctuated by a bunch of annuals, engine changes and miscellaneous repairs, , I own just about a full set of Snap On screwdrivers.

  12. Does seem odd he was unable to diagnose and overcome a reversal of trim effect condition, especially considering it was specifically a “test” hop where anomalies could be expected. Perhaps there were other factors such as a jam or binding related to the miss-rig. Doubtless the final report will provide a clearer picture.

  13. Alas a re-run of this other terrible accident.
    I have 23.500 hrs airline with 5.5k GA hours included. This kind of accidents gives me no dreams of being the hero and walking away alive from these situations. Rightout nightmare scenarios. Forget fighting all moving stabs with elev, no chance.
    IF checking the elev trim tab, don’t make the mistake it is some kind of mini elevator so should go UP, when asking for nose UP trim…It should go DOWN, thus pushing the elev UP in flight…..

  14. After working at a major Part 145 refurb operation, I can say with confidence, most customers simply got into the airplane and leave. Many times bringing the dog, mistress, and business associates with a kick the tires, light the fires attitude. Very few approached the first post maintenance flight with a test pilot mentality, a post maintenance checklist, or any prepared test card. Most did not check the flight controls other than the normal wiggle of the yoke during the normal pre-take off/runup checks.

    I believe the expectation is/was, you are the Part 145 experts, you took my airplane apart during strip/primer/paint, interior, avionics, and engine refurbishment process. You are the experts putting it all back together. You will do it right because you are a Part 145 operation. Since so many pilot/aircraft owners are not even remotely mechanical savvy, they simply trust you put it back together correctly. From the consumer’s standpoint, the Part 145 label means to them the shop meets all the maintenance requirements because they are FAA approved. That implies that they are superior to shops that are not Part 145 certified. Therefore, bring the inlaws, outlaws, girlfriends, and business buddies to see and fly their new shiney, leather aroma filled airplanes for the first time.

    The reality is, there is a severe shortage of qualified FAA certified A&P’s, including those with an inspection authorization at many Part 145 refurbishment shops. That means most of the refurbishment process is done with manpower that has no specialized training working on airplanes. What few A&P’s and IA’s they might have are largely in supervisory positions, mostly chasing down paperwork, locating suitable approved reference documents, searching for parts, or attempting to engineer a mod the customer wants after he has seen another’s corporate chariot that might be of the same type but usually not the same model. The actual work, including removing the flight controls and trim tabs, stripping, painting, re-balancing, and final installation are largely done by workers who are not A&P’s. Few have any idea how an airplane flies, the function of the flight controls, and mostly put the flight controls back on the way they took them off. Rigging is rarely checked. Cost of normal flight control removal, painting, and re-installation does not include rigging them. While there are inspections along the way, many are completed with expectation bias because of the tremendous workload required of the few credentialed workers.

    Another key ingredient in the recipe for disaster is meeting deadlines for aircraft delivery. Promises are made with deals structured for a pre-determined delivery date. Often, these dates are not even remotely attainable. To get the work, shops make promises they know they cannot keep. Shop owners do not want to lose business because they cannot meet a competitors delivery date. But once the airplane is apart, the aircraft owner loses control, and is now at the mercy of the shop. Tempers flare, customers are unhappy, with shop owners applying even more pressure on the paint, interior, and avionics divisions for a hasty completion because the airplane is now several weeks or months beyond the original delivery date. Put it back together and whatever needs further repair, fixing, or tweaking will be done under “warrantee”. This leads to many refurb deliveries late, with impatient, frustrated owners and pilots just wanting to leave. I have witnessed many of these deliveries launching IFR, hard IFR.

    I am not broad brushing Part 145 refurb shops. Those who have A&P credentialed staff, with type rated capable post-maintenance test pilots, and meet their respective delivery deadlines do exist. But they have order backlogs that last years. And they deservedly command the highest shop labor rates.

    Many airplanes are broker owned for a flip, or by private owners looking for a better deal meaning cheaper costs, flight schools working on a thin profit line, or managed by company finances whose check writers are only looking for the least expensive bottom line. These airplanes do not go to the high end shops. They go to those FAA approved Part 145 shops who operate under their certificates with many un-credentialed, unskilled with aviation or new-to-airplane workers, who look at airplanes just like cars, working under “supervision” of A&P’s and A&P/IA’s.

    At the end of the day, there is a severe shortage of quality aircraft maintenance personnel, including those with IA credentials, dealing with 40+ year old airplanes that have already been refurbished at least once if not more in much less than high end shops, creating a demand situation that fosters unrealistic expectations that leads to incredible levels of frustration for the aircraft owner and/or the pilot who ends up picking up the airplane. Don’t like them apples? Where are you going to go for an alternative?

    It does not take much alteration on the flight controls of a high performance airplane to make it uncontrollable. Jimmy Leeward’s P-51 only lost a small elevator trim tab when it crashed into the spectator stands at Reno. Ruddervator trim tabs often are put on upside down yet still work in the right direction. Depending on the rigging of the Bonanza, speed, and the CG at the time of flight that will determine how good or bad it will fly. Most pilots would not notice or be aware of it being upside down. But it happens more often than one would expect.

    I don’t know what happened in this crash, but I would not be surprised that there is a trail of circumstances within the refurbishment of this Navajo that are playing key roles in this newly refurbished airplane becoming a smoking hole. Including unrealistic expectations by both aircraft owner and shop that will, most likely, not be included in the NTSB final probable cause.

    I am surprised there are not more accidents like this considering few look at a post-maintenance check flight any different than any other flight. Trust in a FAA certificates, lack of mechanical understanding, combined with unrealistic delivery expectations makes for a dangerous stew that can lead to a wreck. I am sad for that Navajo pilot who had his hands full with expectations his shiney, new looking airplane would fly as well as it looked.

  15. One time after I did an annual on my Cessna 172, I did a post inspection checkout flight and immediately noticed the elevator forces didn’t feel right. Since I’ve been flying that same airplane for decades, I know it intimately. It wasn’t so horrible that it was an emergency but it was “different.” Wracking my brain in flight, I decided that there was a possibility that I might not have put the trim tab access plate back on. I have the habit of taking two of the three screws out, rotating the plates 180 deg and hand tightening the screws into their tinnerman nuts … that way I don’t have to search for things upon finishing.

    Anyhow … when I landed and walked back … sure enough, that plate was turned forward and was spoiling the airflow over a portion of the trim tab … which is why it felt different. I calculated how much and it wasn’t much but enough to feel. Once I put it back on correctly, all was back to normal. The reason I missed it is because I didn’t get onto my knees to inspect things … it’s easy to miss. And, I had a sore knee so I was babying it.

    This is one of the reasons why when I do my own QC, I either walk away from a task and come back later OR — better still — do it a subsequent day when I’m fresh.

    Shows to go ya how easy it is to make a mistake. Guess what’s on my preflight mental checklist now.

    Several people are talking about the shortage of qualified A&P’s and IA’s. All the more reason that EAA recommended “Primary Aircraft Category” should have been implemented into the FAR Part 23 rewrite. An owner who gets some schooling and works with an A&P would usually be in a better position to do maintenance than some 18 year old A&P wannabe with no vested interest in what he/she is doing.

    • Larry, you are preaching to the choir. I have lobbied for years to have the FAA allow owners to be certified to work on their own aircraft. I’m not an A&P, but as you say, it is my butt in the sling when the plane leaves the ground, so I’m motivated to make sure it is done right. I have an A&P/IA that allows me to participate in the annual inspection. If he didn’t I would find another mechanic. It is a good learning experience for me, and it relieves him of the grunt work of removing inspection covers, etc. Plus, I get to see what he inspects and I learn how it all functions. Having said that, I have never had to verify proper placement of control surfaces following removal, so a checklist would be helpful.

  16. Yes there is a AD on the Beech Sierra/Sundowner . If you are looking for it then go to the FAA site and find it, free and available to anyone. Another one is Beech 91-17-01 that deals with the ability to install the trim actuator on the wrong side, reversing the tabs. Straight tail Bonanzas and Twins. Regarding owner involvment in maintenance…. based on my couple years in the industry (45) I have met only a couple owners that have the moxie and the skills to work on their own plane. ( under my supervision ) Its one thing to be a good wrench, totally another issue staying within part 23 requirements and good practices. Unfortunately, not all IA’s are equal too, compounding issues. I’ll teach anyone that wants to learn. Despite all the safeguards we can put in place, these accidents still happen, from GA up to Majors and Corporate. I’m still looking for solutions after all these years. (SMS is not one of them)