According to the Designated Pilot Examiner, following steep turn maneuvers during a check ride for a multi-engine rating, he and the flight instructor heard a “loud metallic bang” from the tail of the Piper PA-34-200 and the control yoke abruptly went to the full nose-up position.
He told investigators the nose of the airplane pitched up rapidly and the stall warning went off as they entered an accelerated stall.
He took control of the airplane and applied full power to recover from the stall, at which time they heard another loud bang from the tail and the nose of the airplane pitched abruptly down.
He reduced power to idle, there was another bang, and once again the airplane pitched up uncontrollably. This time he did not add power and the nose of the airplane pitched down, but not as severely and he was able to use the engine power to dampen the pitch oscillations.
Unable to maintain full control of the airplane, he elected for an emergency, off-airport landing near Coldspring, Texas.
While on the final approach, as the airplane clipped the tops of trees, the DPE pulled the mixture controls to cutoff. Upon touchdown, the airplane bounced then slid through a rough, muddy field, which resulted in substantial damage to both wings, the fuselage, and empennage.
The DPE and flight instructor sustained serious injuries in the crash.
A post-accident examination revealed that the bolt that connects the stabilator trim rod assembly to the stabilator link assembly was missing.
A review of maintenance records revealed two maintenance logbook entries for the elevator trim wheel cable becoming unspooled, the first on March 14, 2023, and the second on March 23, 2023. After each repair, a functional check flight was accomplished with no discrepancies noted.
In an interview with the mechanic from the March 23 repair, he stated that he did not disconnect or otherwise perform maintenance on the affected control rod or linkage.
The pilot examiner stated that during the preflight inspection, no anomalies were noted with the trim linkage assembly.
Following the accident, the flight school inspected all PA-34 airplanes in its fleet and replaced the affected bolt on each airplane.
Probable Cause: The stabilator trim rod assembly separated from the stabilator link assembly due to a missing connecting bolt, which resulted in the pilot’s inability to maintain pitch control of the airplane.
To download the final report. Click here. This will trigger a PDF download to your device.
This May 2023 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
I read the accident report and the comments from the instructor were startling to me. He applied full power which lowered the nose. The aircraft then pitched down and he reduced the power and the aircraft pitched up. He was able to control the aircraft somewhat and bring the aircraft close to the ground. His comments are so important as to how to survive this experience. Had they not survived we may never know how to respond and bring the aircraft in to a survivable landing.
I could only imagine his thoughts and thank him for this information. I completely understand how he managed to over come the situation.
My point here is this is exactly what FAA/NTSB needs to do. Discuss this and have safety seminars on how to respond to such emergencies.
Thanks to the this instructors flight experience he saved himself and his student and did not hurt anyone one the ground
This is exactly why I published my elevator failure article and still give seminars on how to survive a problem with a crippled aircraft.
FAA NEEDS TO DO THIS.
Thank you
Rich Wyeroski
If you use a nuts up approach on connecting, and some red fingernail polish you can see it easier if a nut is loosening.
Most people just look at the bolt head and think everything is good without ever checking the bottom for the nut.
JMO.
Darlene
I am so glad you survived to discuss what happened. You came back and got your rating and with the same DPE……Great!
You have the right stuff to be successful in anything you do !
I am a high time instructor/IA and former FAA inspector. I have been involved with accidents and unfortunately they keep happening.
I would like to see the FAA/NTSB work together and have seminars on how to prevent accidents and how to survive and operate a crippled aircraft.
I personally have lost all three flight controls over the years. I left a gust lock on the rudder as a student years ago. I learned from that error. My ailerons were jammed on a small twin because the auto failed and jammed the ailerons. Lastly my lateral control was effected when my elevator detached in flight causing the aircraft to be uncontrollable….
I survived to discuss the last one and yet the FAA never issued an AD at my request. The NTSB report was excellent and showed the problem. However it never discussed how to survive !…..WHAT TO DO IF!!!!
My point is we need to discuss and train on how to survive when something like this happens and prevent it from happening again.
FAA spends millions each year on seminars and in my career I attended 100s over the years.
I have given seminars on my own on how to survive these failures in flight and why they happen
So Good luck Darlene and go forward with your career
Regards
PS this was published here 7 years ago
ELEVATOR FAILURE AT 4500 FEET
https://airfactsjournal.com/2018/12/elevator-failure-at-4500-feet-in-a-cessna-150/
Mechanics need to check their work. Even if the a nylon lock nut is reused and it is worn, it won’t loosen up if it’s tightened properly. I worked piston GA for a long time. Now working in corporate. It is interesting to see the differences of certification standards. Primary controls are redundant. They use locking castellated nuts. Tabs to prevent bolts from backing out if the nut falls off. These are all things that experience has taught FAA are necessary.
The DPE performed a miracle in them both not dying. A free flying stabilator? Omg. That’s nightmare material. Excellent work by the DPE.
Post maintenance and they didn’t touch it ?… Sure thing buddy. Seen that before. Good lawyer and good advice.
It’s possible the Nylock nut was reused. That is strictly forbidden. The nut could have worked itself loose before allowing the bolt itself to work itself out.
The nylock stop nut is allowed to be reused, up to 15 times, as long as the minimum retention torque is achieved. But, the minimum is only about 20% of the new torque.
So, why reuse them, especially when most of the smaller sizes are about $0.20 ??
I would not be surprised if the nut was left off due to a cell phone interruption and the bolt eventually worked out. Such an error could have happened YEARS ago. I kept a small clipboard handy to jot down uncompleted tasks like this so that I would not forget.
Mechanics training includes installing a bolt’s head positioned UP or FORWARD (if there is a choice) helps; but does not always work successfully to prevent such an occurrence.
Jerry King
What a surprise to see this in my email box haha. I was the checkride applicant in this accident and wanted to say thank you for sharing our story. I hope it is informative for pilots and mechanics. To be clear, we did a thorough preflight and no abnormalities were found. I get asked a lot if I passed the checkride, but unfortunately it was decided to be “discontinued.” Once I was healed and the FAA cleared my medical 7 months later, I reattempted the checkride with the same DPE and passed. I am extremely blessed to be alive and healed. I hope that no one goes through what we did, but may our story insightful none the less.
D, I’m glad to hear that you’ve recovered and passed your checkride..!!!
Was it ever found out how the trim rod bolt came loose and fell out.?
A nylock nut should have never come loose.!
So glad you made it out, and continued to pursue your flying dream! I wonder if I would have had the guts!
My bet is someone is lying, or it’s a CYA story and there IS a mechanic or maintenance facility that flubbed-up BIG time. Moral of the story is this: ALWAYS RE-CHECK ANY MAINTENANCE ITEM THAT HAS BEEN TOUCHED BY AN A&P… ESPECIALLY in critical component areas such as this. If you don’t, chances are YOU WILL BE the next accident.
Looking at the service manual, 761 590, the trim tab hardware uses an MS 20365-1032C nut, which is a fiber , self locking nut.
So, it was either very worn and un-threaded itself, as was the nut on the P-51 at Reno, or the wrong hardware was used that was not properly secured .
Good piloting!
For the want of a nail the shoe was lost,
For the want of a shoe the horse was lost,
For the want of a horse the rider was lost,
For the want of a rider the battle was lost,
For the want of a battle the kingdom was lost,
And all for the want of a horseshoe-nail.”
― Benjamin Franklin
Pilots and mechanics look at aircraft differently!…….Maybe we all should work together. Possibly FAA should have seminars on aging aircraft and what to look for….?
…strange to see a clean (input) bracket compared to the other parts surrounding this disconnected rod / missing bolt. It seems new(er), so how can this bolt just disappeared and or broken of / out…? so no maintenance lately to this part… or cleaned for post investigation? it doesn’t add up…
I’m guessing the student didn’t pass the checkride?
This crash and the P-51 at Reno, both from trim tabs disconnecting….sad.!
One of the items on my Cessna pre-flight check list is to lift the elevator and check the 2 sets of hardware on the trim tab pushrod.
I also grab both side of the elevator and check for looseness in the torque tube rivets.
[ a Cessna item]
I check the aileron hinges, to be sure the hinge pins are visible at both ends…
Any of these not connected correctly can kill us.!!!
I’ve replaced a number of moving parts, like these on my 64 YO Cessna…’nothing lasts forever’…