What happened
On October 29, 2003, at 16:19, a Dornier Alpha Jet departed from Oberpfaffenhofen Airfield under Visual Flight Rules (VFR). The flight was part of a training program intended to help a pilot obtain a civilian type rating for the aircraft. The crew consisted of a trainee pilot in the front cockpit and an instructor in the rear seat.
After departing runway 22, the aircraft flew south toward Penzberg before turning east. Witnesses observed the aircraft performing low-altitude maneuvers near Waakirchen and later near the Wendelstein weather station at approximately 1,900 m MSL. Radar data indicated flight speeds between 280 and 310 knots.
As the aircraft approached the Inntal region near Brannenburg, witnesses reported seeing the aircraft perform a loop at an altitude of approximately 200–500 m AGL, accompanied by a roll around its longitudinal axis. Following this maneuver, the aircraft appeared to lose speed in level or slightly climbing flight, followed by a left turn and a subsequent left bank. The aircraft then entered a steep descent, potentially involving two to three spins, and struck the ground near Brennenburg. The impact caused the aircraft to disintegrate and triggered an explosion and fire. Both pilots were killed in the accident.
The investigation
The BFU investigation focused on the aircraft's condition, the flight path, and the mechanical state of the control systems. The aircraft, which had been decommissioned since 1993 and was being prepared for civilian use, lacked a flight data recorder or cockpit voice recorder. Investigators relied on primary radar data and witness accounts to reconstruct the flight path.
Investigators examined the two engines, the hydraulic control cylinders for the elevators and ailerons, and the wreckage at the impact site. The investigation also addressed the specialized nature of the aircraft's recent demilitarization, which involved removing the original military ejection seats and replacing them with a manual canopy jettison system and conventional parachutes for civilian compliance.
Findings
- The aircraft was operating under a provisional airworthiness certificate as part of a wide-range testing program.
- The Alpha Jet had been demilitarized for civilian use, meaning the Stencel ejection seats and their associated pyrotechnic firing systems had been removed and deactivated.
- The impact occurred in a meadow, creating a crater 5–7 meters in diameter; the high water table at the site significantly hindered the recovery of debris.
- Examination of the hydraulic control cylinders showed no significant signs of wear or internal failures prior to the impact; however, the impact forces were so extreme that the control rods were broken or bent.
- The engines were found to have been under full power at the time of impact, as both thrust levers were positioned at maximum power.
- The investigation found no evidence of engine failure or unusual engine noise prior to the loss of control, though the aircraft's flight path became erratic during the final maneuvers.