North Las Vegas, NV, USA
N8232M
Cessna 210K
On the first flight following an annual inspection, in night, visual meteorological conditions, when the pilot attempted to retract airplane's landing gear, the gear would neither fully retract nor fully extend. The pilot attempted to extend the landing gear using the emergency manual extension hand pump. He reported the ". . .pump handle was locked solid and would not move. . ." He couldn't get the selector handle to recenter as it was supposed to and he didn't get a landing gear extended cockpit indication. The pilot elected to return to the departure airport. The pilot performed a flyby past the air traffic control tower and the controller radioed that all three gear appeared to be down; however, the pilot's wife, in the right seat, told him she couldn't see a wheel on that side of the airplane. During the ensuing landing, the right main landing gear collapsed, the right wing contacted the runway, and the airplane veered off the runway to the right. The aircraft was delivered for the annual inspection with a landing gear extension discrepancy. A misrigging problem on the left main landing gear seemed to explain all of the symptoms and was repaired. The gear was satisfactorily cycled 10 times using an external hydraulic pressure source (mule). Inspection subsequent to the accident revealed that, although functional, the output of the engine-driven hydraulic pump was deficient and insufficient to operate the gear. The emergency hand pump and emergency gear extension system operated normally. The maintenance facility manager speculated that the reason the pilot was not able to extend the landing gear with the emergency hand pump was because he didn't first fully extend the handle. If the telescoping handle shaft is not fully extended the handle cannot be moved and feels similar to a "hydraulic lock."
On November 9, 2001, at 1849 Pacific standard time, a Cessna 210K, N8232M, veered off the runway when the right main landing gear collapsed during landing at North Las Vegas, Nevada. The private certificated pilot and one passenger were not injured. The airplane was substantially damaged. The personal flight was operated by the owner under 14 CFR Part 91. The flight originated from North Las Vegas and was destined for Lancaster, California; however, after takeoff the landing gear would neither fully retract nor fully extend and the pilot elected to return to North Las Vegas. Night, visual meteorological conditions prevailed and a visual flight rules flight plan was filed. According to an inspector from the Federal Aviation Administration Las Vegas Flight Standards District Office, the accident flight was the first flight of the airplane following an annual inspection. The aircraft was delivered for the annual inspection with a landing gear extension discrepancy and the repair facility reported they re-rigged the landing gear and then placed the aircraft on jacks and successfully cycled the gear 10 times using a external hydraulic pressure source (mule). Inspection subsequent to the accident revealed the output of the engine-driven hydraulic pump was deficient. The pilot reported that, the landing gear did not fully retract and subsequently would not extend and lock down either. The pilot attempted to extend the landing gear using the emergency manual extension hand pump. He reported the ". . .pump handle was locked solid and would not move. . ." He couldn't get the selector handle to recenter as it was supposed to and he didn't get a landing gear extended cockpit indication. He manually moved the selector to the center position. The pilot performed a flyby past the air traffic control tower and the controller radioed that all three gear appeared to be down; however, the pilot's wife, in the right seat, told him she couldn't see a wheel on that side of the airplane. During the ensuing landing the right main landing gear collapsed, the right wing contacted the runway, and the airplane veered off the runway to the right. The manager of the maintenance facility that performed the annual inspection told the Safety Board investigator that, during the inspection, his mechanic had identified a serious misrigging problem on the left main landing gear that seemed to explain all of the symptoms the owner had told them about. The misrigging was repaired and the gear was satisfactorily cycled 10 times using a hydraulic mule. Following the inspection, the airplane was taken outdoors, the landing gear doors were manually opened, and the engine was started. The gear doors closed, indicating the engine driven hydraulic pump was operational. Following the accident, the airplane was hoisted and the landing gear was extended and locked down using the emergency hand pump. Back at the hangar, the gear doors were manually opened and a pressure gauge was attached to the hydraulic pump output line. When the engine was started the doors closed but the pump output pressure on the gauge was low and the gear handle would not recenter. On a repetitive check the pressure was insufficient to even close the doors. Disassembly examination of the pump revealed a ruptured diaphragm, which was bypassing fluid and thereby reducing output flow and pressure. The facility manager speculated that the reason the pilot was not able to extend the landing gear with the emergency hand pump was because he didn't first fully extend the handle. If the telescoping handle shaft is not fully extended the handle cannot be moved and feels similar to a "hydraulic lock." When it was checked after the accident, the emergency hand pump and emergency gear extension system operated normally.
The failure of maintenance personnel to properly diagnose the cause of a reported maintenance discrepancy resulting in the airplane being released from an annual inspection with a worn hydraulic pump which lacked sufficient output to operate the landing gear. Another cause was the pilot's improper execution of the landing gear emergency extension procedure by failing to fully extend the manual hydraulic pump handle prior to attempting emergency gear extension.
Source: NTSB Aviation Accident Database
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