Incident Overview
On August 8, 2023, at about 1500 Pacific daylight time, a Piper PA-24-260, registration N503JA, was substantially damaged when it was involved in an accident near Fullerton, California. The pilot sustained minor injuries. The airplane was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Account
The pilot reported that shortly after takeoff, the airplane began to shake violently. The control yoke moved rapidly forward and aft, from stop to stop. The vibrations were so extreme that he assumed the engine had suffered a catastrophic failure, such as a detached engine cylinder. He shut down the engine and turned the airplane back toward the airport. The pilot stated that he was able to land, but sustained hand injuries due to the extreme control forces and oscillations.
Aircraft Damage and Examination
The airplane sustained substantial damage to the stabilator structure. A postaccident examination revealed that the stabilator tab actuator was disconnected from the control tab, and the bolt, nut, and washer that connected them were missing. The tabs exhibited extensive scratch and peening damage to both their inner and forward surfaces, consistent with high-frequency oscillations. The paint around the end of the tab actuator arm had chipped away, revealing similar peening damage to its steel surface.
Neither the bolt nor the nut that connected the tabs to the actuator were located. There was circumferential scoring around the bolt hole bore in the tabs, but neither bolt hole appeared elongated. The bushing within the actuator did not appear out of round.
Maintenance History
According to the airplane’s illustrated parts catalog, the actuator retaining nut was supposed to be a self-locking type, with no provisions for a cotter pin. The mechanic who had performed an annual inspection 5.5 flight hours before the accident stated that he did not remove or replace either the bolt or the nut, and that he performed a functional check of the pitch trim system with no anomalies noted. Examination of the maintenance logbooks did not reveal any evidence that the nut had been replaced since the airplane was manufactured in 1965.
Conclusion
The investigation determined that the stabilator tab actuator was disconnected from the control tab due to missing hardware, leading to the in-flight oscillations and subsequent forced landing. No probable cause was explicitly stated in the source material.