What happened
On April 2, 2000, a Cessna 441 departed Dortmund Airport to conduct a training flight for a type rating. The flight proceeded north, exiting the Dortmund control zone. West of Werne, the aircraft performed a series of maneuvers, including a left turn followed by a right turn. During the right turn, the aircraft experienced a significant loss of altitude, dropping from FL 27 to FL 15 with a sink rate between 2,000 and 3,000 ft/min.
As the aircraft attempted a climb from FL 29 to FL 38, the airspeed dropped to between 75 and 90 KCAS. This was immediately followed by a steep descent with sink rates exceeding 4,500 ft/min. Radar tracking showed the aircraft entering a nearly vertical descent at approximately 85 KCAS, with sink rates reaching as high as 8,900 ft/min in the final seconds before impact. Witnesses described a "corkscrew" motion and observed the aircraft striking a field near a farm in a flat attitude with engines at high power.
Both occupants sustained fatal injuries due to the high energy of the impact. Notably, neither occupant was wearing a seatbelt at the time of the crash.
The investigation
The BFU examined the aircraft, the engines, and the flight history of the crew. The investigation established that the aircraft was airworthy and that the engines showed no mechanical defects. The investigation also reviewed the pilot's experience, noting that the instructor was highly experienced with over 13,500 flight hours, while the trainee had approximately 1,800 hours.
Investigators also looked into the meteorological conditions and the flight maneuvers. The investigation found that the weather was unsuitable for the intended maneuvers, as the cloud base was approximately 4,000 ft AGL, whereas the manufacturer's manual recommends that stall training should not be conducted below 5,000 ft AGL.
Findings
- The primary cause of the accident was that the instructor was unable to recover from the spin once it developed.
- The altitude at which the maneuver was initiated was insufficient to allow for a safe recovery.
- The flight maneuvers were being conducted below the altitude recommended by the manufacturer for stall training.
- A similar incident had occurred approximately four weeks prior, where a stall maneuver resulted in a loss of 2,300 to 2,800 ft before recovery.