On August 23, 1985, a Beech B19 (registration N9718L) was involved in an aviation accident near Van Nuys, CA. Investigators recorded the probable cause as: The shearing of the right inboard aileron control push rod at the forward end due to a seized bearing caused by a lack of lubrication. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
The pilot executed a successful landing after the right aileron disconnected at 800 feet due to a sheared control push rod caused by seized bearings and lack of lubrication.
What happened
Shortly after takeoff, the aircraft reached an altitude of approximately 800 feet when the right aileron suddenly became disconnected from its control system. Despite this critical mechanical failure, the pilot maintained control of the aircraft. The pilot managed to execute a left turn and established a left-hand traffic pattern. The pilot then proceeded to land the aircraft successfully without further incident.
The investigation
A post-accident examination of the airframe revealed the specific mechanical failure responsible for the loss of control surface functionality. Investigators found that the right inboard aileron control push rod had sheared at its forward end. Further inspection indicated that the bearing associated with this component had seized. Evidence showed a distinct lack of lubrication, which contributed to the bearing seizure and subsequent structural failure of the push rod.
Findings
The primary factor leading to the incident was the mechanical failure of the right inboard aileron control push rod. This failure was directly caused by the shearing of the rod at the forward end, which resulted from a seized bearing. The root cause of the bearing seizure was identified as a lack of lubrication within the control system components.
Probable cause
The shearing of the right inboard aileron control push rod at the forward end due to a seized bearing caused by a lack of lubrication.