This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
After trimming for level flight and while adjusting the prop for cruise, the Cessna 182 suddenly started shaking violently at a regular and high frequency.
Thinking that something had gone wrong with the prop, I reduced throttle to try to reduce the severity of the shaking, but this had no apparent effect.
Engine oil pressure and temperature were both well within the green range. We had just departed a nearby airport, so turned around to land. I noticed that keeping the nose of the airplane up required significant back pressure. Adjusting the trim appeared to have no effect.
Enroute to the airport the shaking suddenly stopped. We continued to land without incident.
After stopping the airplane on the ground we inspected the trim tab and found that it was stuck in the nose-down position. Looking underneath the elevator, we found that the trim-tab control rod was not connected where it usually met the horizontal stabilizer. The end of the trim-tab control rod towards the stabilizer appeared to have been bent and broken. It appeared that at some point the rod broke and jammed.
After replacing and reattaching the trim control rod the airplane is operating normally and has been returned to service.
Speculation is that at some point the bolt connecting the rod had either partially failed or come loose, causing uneven stress on the control rod, eventually resulting in failure due to metal fatigue. The elevator trim cable had recently been replaced but it is not clear if the control rod had been touched as part of that work. Inspection of this connection point can be done simply and quickly during pre-flight and may benefit from increased awareness as a possible or likely point of failure.
Primary Problem: Aircraft
ACN: 1792193
Unfortunately not everyone can but anything requiring an A&P/IA, I open, they perform service, I inspect and close. Amazing what is found….like a missing nut on a front landing gear door linkage bolt after being worked on during an annual. Or a P lead worn through and grounded coming out of annual. Completely visible wear, center conductor showing, tie strapped to two brackets and at mag connection. Although the mag functioned going in it was apparently moved enough to short and delivered back that way. Was putting it back in the hangar and something told me to do a runup. That’s when I starting inspecting and closing myself.
Plan was a 4 am departure straight across the Rookies, bad time to catch it during runup.
JS & David — ++1
Fortunately he landed safely! I had this happen on a DHC-6 Twin Otter with a full load of jumpers (23 souls) after take-off passing through 1000ft. The shaking was so severe that my door opened and kept slamming. It disconnected my headset, lucky I made all radio calls necessary. Not high enough for jumpers to jump and survive, I took the airplane to another airport straight ahead and declared an emergency. The slower I flew to land, the less the shaking. After landing everyone applauded. The elevator trim tab had broken off. It was a very intens flight to say the least but I kept cool. FAA investigated. Focus on flying it till the end, never give up.
The tail of the 182 deserves a thorough damage inspection after the beating it took from trim flutter. Additionally, with trim flutter, deploying full flaps can change the air flow over the tail and may moderate the trim flutter. I had this situation on my aircraft (not a 182). The trim flutter was severe enough that I decided to land off field. When I pulled in full flaps on the approach, it moderated the flutter enough that I was able to fly another 6 miles to the nearest airport. I did find internal damage in the tail after this incident as well as significant damage to the trim tab mounting.
This person was very lucky the rod *jammed* as opposed to free fluttering. Though this seems like a minor part for control, many planes have been lost with trim tab failures: VITAL. This was the cause of Jimmy Leewards P-51 crash into the crowd a Reno: https://www.popularmechanics.com/flight/a8074/investigators-id-cause-of-reno-air-races-crash-12141717/