NTSB Identification: MIA99FA159.
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Accident occurred Thursday, May 20, 1999 in TAMARAC, FL
Probable Cause Approval Date: 03/09/2001
Aircraft: Classic Aircraft Corp. S-51D, registration: N25VV
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
On the morning of the accident the airplane had flown for about 1.2 hours, landed, was refueled, and shut down for a an unknown period of time. After start up the pilot taxied to the active runway, and was delayed in taking off by ATC, due to traffic. The time between engine start and takeoff was about 16 minutes. About 11 nautical miles west of the airport, the pilot radioed the control tower that he was having a problem raising the landing gear and he wanted to return to the airport. The pilot then radioed that he had lost the engine. Radar and radio contact was lost shortly thereafter. A witness heard the engine losing power, and sputtering. The witness also observed the airplane make a controlled descent towards the ground. On-site examination revealed that the approximately 10-foot-high brush, to the west of the ground impact site was bent towards the east, and the area of bent brush was about 20 feet in length. There were no ground scars to indicate that the airplane had any forward movement after impacting the soft ground. A test run of the engine was performed and revealed that when the engine was brought to cruise RPMs, and running for about 10 minutes, the fuel temperature reached 153 degrees F, which set up a vapor lock condition, the fuel pressure needle fluctuated, went to zero, and the engine completely shut down. The engine was allowed to cool and then started again. On the second run the fuel temperature reached 152 degrees F, the RPM and fuel pressure fluctuated, and the engine completely stopped, similar to the first run. A test on a similar airplane revealed that while cycling the landing gear, the wheels would pass in front of the radiator scoop. With the gear partially up, but not in the wheel well, the gear almost completely blocked the radiator scoop, which would have caused cooling air to be blocked or deflected.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: A complete loss of engine power caused by the malfunctioning landing gear, which blocked the radiator scoop, leading to increased fuel temperature and the subsequent vapor lock condition and fuel blockage. A secondary cause was the pilot's failure to maintain flying speed resulting in the subsequent stall/mush Full narrative available
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