NTSB Identification: MIA05LA079.
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Accident occurred Saturday, March 12, 2005 in San Juan, PR
Probable Cause Approval Date: 10/27/2005
Aircraft: Rockwell Aero Commander 500, registration: N8498C
Injuries: 4 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
Maintenance had been performed to the left main landing gear actuator and flexible hoses that connect to it earlier in the week. The mechanic who performed the work did not complete retraction tests of the landing gear and did not approve the airplane for return to service. The pilot stated that braking action was normal during taxiing, but after takeoff, at approximately 1,000 feet above ground level (AGL), the main gear would not retract and he noticed the hydraulic pressure gauge indicating 0 pressure. He selected gear down, observed three green lights, used the hydraulic emergency hand pump, and turned back to the airport. While operating the hydraulic emergency hand pump, he noticed "some pressure" up to 800 psi. While returning to the airport he moved the emergency hand pump selector valve to "brake only" to be able to stop the airplane but reported he did not get any pressure when using the emergency hydraulic pump. On final approach he slowed the airplane to approximately 85 miles per hour, touched down, and started pumping the hydraulic emergency hand pump for the brakes, with no success. Unable to stop the airplane, it collided with a ditch beyond the departure end of the runway. Following recovery of the airplane, the emergency hand pump selector valve was not found in the "brakes only" position. Operation of the hydraulic emergency hand pump with the selector set to "brakes only" revealed hydraulic pressure was produced. NTSB review of the airplane's Maintenance Manual reveals that the emergency hand pump selector valve, located between the pilot and co-pilot seats, provides a means of directing the flow of hand pumped pressure to either the brake system or the normal hydraulic system. With the selector valve in "brakes only" position, only the wheel brake system and nose steering cylinder received hand pump pressure which will not be indicated on the hydraulic pressure gauge.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The failure of the pilot to follow the emergency checklist and his inadvertent operation of the airplane with known discrepancies resulting in landing overrun and on-ground collision with a ditch during the landing roll. Full narrative available
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