On November 1, 1983, a Piper PA-23-250 (registration N40249) was involved in an aviation accident near Greer, SC. Investigators recorded the probable cause as: An aileron balance cable chafed against a hydraulic line in the landing gear system until a hole was worn through the line, allowing the hydraulic fluid to leak out. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During flight, hydraulic failure prevented landing gear from locking. After orbiting over an hour, the gear collapsed on landing. Investigation revealed an aileron balance cable had chafed through a hydraulic line, causing fluid loss.
Incident
During the flight, a hydraulic failure of the landing gear system occurred. The aircrew was unable to get the landing gear locked in the down position. After orbiting for over an hour, a landing was made. During touchdown, the gear collapsed.
Examination
A detailed examination of the aircraft was conducted to determine the cause of the hydraulic failure. The examination revealed that an aileron balance cable had chafed against a hydraulic line in the landing gear system. The chafing continued until a hole was worn through the wall of the line. This hole allowed hydraulic fluid to leak out of the system. The loss of hydraulic fluid resulted in insufficient pressure to lock the landing gear in the extended position. When the aircraft landed, the gear was not properly locked and collapsed under the load. The investigation did not identify any other contributing factors.
Probable cause
An aileron balance cable chafed against a hydraulic line in the landing gear system until a hole was worn through the line, allowing the hydraulic fluid to leak out.