What happened
On November 28, 1998, at approximately 15:35 local time, a mid-air collision occurred at the Marl-Loemühle airfield in Germany. The incident involved two high-wing aircraft: a Cessna F 150 L and a Cessna F 172 H.
The pilot of the Cessna F 150 L had chartered the aircraft from a local flight school for an introductory flight, accompanied by an experienced pilot to familiarize the operator with the local traffic pattern. The aircraft departed from runway 25 at 15:33. Simultaneously, the Cess and F 172 H was returning from a 50-minute flight, announcing its intention to join the south pattern for landing.
During the transition from the departure turn to the downwind leg, the two aircraft collided. The propeller of the Cessna F 172 H struck the tail section of the Cessna F 150 L, severing its vertical stabilizer. The Cessna F 150 L subsequently crashed into an open field near the A 43 autobahn, resulting in the death of both occupants. The Cessna F 172 H sustained minor damage but remained controllable, allowing the pilot and passenger to land safely without injury.
The investigation
The BFU investigation reconstructed the flight paths using radar data and physical evidence. While multiple aircraft were using the same transponder code, the radar track for the Cessna F 172 H was identified through its alignment with the pilot's statement. The Cessna F 150 L's path was harder to track as its transponder was not activated upon departure.
Analysis of the impact marks on the Cessna F 150 L's fuselage and tail revealed that the collision occurred at an angle of approximately 52 degrees from the rear right. Based on the propeller RPM, the investigators estimated a relative closing speed of approximately 67 knots. The investigation also noted that the pilot of the Cessna F 172 H had observed another aircraft in the pattern earlier but lost visual contact during a right-hand turn.
Findings
- The crew of the Cessna F 150 L failed to maintain adequate lookout and did not sufficiently monitor the radio frequency, likely due to the high workload associated with the introductory flight.
- The pilot of the Cessna F 172 H underestimated the closing speed of the other aircraft and failed to take timely evasive action before losing visual contact with the Cessna F 150 L.