Piper PA-24-260 N503JA accident near Fullerton, California

Probable cause

The separation of the stabilator actuator from the stabilator tab, which resulted in pitch control surface flutter and structural damage.

NTSB analysis

Shortly after takeoff the airplane began to shake violently with the control yoke moving rapidly forward and aft from stop to stop. The pilot was able to perform an on-airport emergency landing after shutting down the engine, but sustained hand injuries due to the extreme control forces and oscillations.

The airplane sustained substantial damage to the stabilator structure in a manner consistent with it exhibiting aerodynamic flutter. 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 disconnection of the actuator allowed the tab surface to uncouple, which resulted in flutter and structural damage to the stabilator.

Circumferential scoring around the bolt hole within the tabs indicated that the bolt was likely loose for an undetermined period before failure. The nut had likely not been replaced since the airplane was manufactured almost 60 years before the accident, so its locking properties would have been significantly diminished.

Text from the NTSB. Open the NTSB docket for WPR23LA317 for the full record.