NTSB Identification: FTW99LA023.
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Accident occurred Tuesday, November 10, 1998 in TULSA, OK
Probable Cause Approval Date: 03/31/2000
Aircraft: Beech 35-C33, registration: N24TH
Injuries: 1 Serious,3 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The aircraft's engine lost power due to severe detonation shortly after takeoff. During the ensuing forced landing on a road, the airplane collided with trees and the road median. The pilot stated that he had leaned the mixture during climb to 30 gallons per hour because the fuel flow gauge was indicating 'red line of about 35 gallons per hour.' During the climb, the engine RPM started to 'over speed.' The pilot stated that he attempted to reduce engine RPM with the propeller control then subsequently with the throttle; however, the engine 'quit.' Examination of the engine revealed that all of the cylinders showed signs of severe overheating and characteristics of lean mixture operation and detonation. According to the performance charts, the fuel flow should have been set to approximately 20.5 gallons per hour. The complete engine fuel system was bench checked revealing no anomalies that would have prevented normal operation of the engine. Post-accident testing of the fuel flow gauge revealed that the gauge operated correctly and indicated fuel flow properly.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The loss of engine power due to detonation for undetermined reasons. A factor was the lack of suitable terrain for the forced landing.

Full narrative available

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