What happened
On July 23, 1999, a Reims Aviation F 150 L departed from Mannheim-Neuostheim for a training flight to Speyer, carrying a flight instructor and a student. The instructor's plan involved practicing touch-and-go maneuvers and subsequently allowing the student to perform solo circuits.
During the flight, the crew performed a touch-and-go on runway 35, followed by a right-hand circuit. As the instructor began a subsequent climb-out without touching down, he reported engine problems. Air traffic control observed the aircraft flying straight for a short period before entering a left-hand turn, which subsequently led to a descending spiral.
The aircraft struck a road running perpendicular to the runway departure path with a high longitudinal pitch. The impact on the asphalt was severe, compressing the fuselage up to the leading edge of the wings. The wreckage finally came to rest against the airfield perimeter fence. The flight instructor sustained fatal injuries, while the student survived with serious injuries. The accident also resulted in damage to a parked car and the airfield fence.
The investigation
An investigator from the BFU examined the wreckage on-site and found no structural defects in the airframe. While the student's memory of the event faded over time, his initial accounts corroborated the occurrence of engine issues during the initial climb.
Technical examination of the engine revealed that the propeller flange had broken from the crankshaft. Although the engine sustained impact damage to the front left cylinder and the carburetor intake, the internal components, including the pistons, cylinders, and bearings, were in good mechanical condition. Both magnetos showed good performance during testing. The mixture control lever was found fixed in the "full rich" position. However, combustion patterns on the spark plugs suggested a lean fuel-air mixture during operation.
Findings
- The investigation could not identify a specific technical cause for the engine malfunction.
- Because the mixture lever was found in the full rich position, the crew could not have caused a lean condition by manual adjustment.
- While a temporary fuel supply disruption was possible, the engine was likely running at partial power at the time of impact.
- The primary cause of the accident was the pilot's decision to attempt a climbing turn back to the runway after having already passed over terrain that was unsuitable for an emergency landing.