Accident Details
On 23 September 2000 at approximately 16:45 local time, a Bell 407 helicopter crashed in a rapeseed field near Bliedersdorf, Germany. The helicopter was being operated by its owner-pilot on a local flight from a private helipad. Witnesses reported observing the helicopter flying at low altitude near the landing area before disappearing to the east. It then reappeared from the south on a northerly approach. About 250 meters from the landing pad, at a height of approximately 50 meters, the helicopter executed a right turn, began descending rapidly, and struck the ground in a near-horizontal attitude with minimal forward speed. The impact caused the helicopter to roll left, the main rotor to strike the ground, and the tail boom to separate. One rotor blade was thrown approximately 100 meters away. The pilot sustained serious injuries, and the helicopter was destroyed. Crop damage also occurred.
Pilot Information
The pilot, who also owned the helicopter, held approximately 700 hours of flight experience, predominantly on the Bell 206 L4 Long Ranger. He had obtained his type rating for the Bell 407 one year prior to the accident but had not flown the model until a few days before the accident, when he completed 1 hour and 50 minutes of refresher training with an authorized instructor. The pilot could not recall the accident sequence and was unable to provide a statement.
Technical Examination
Examination of the wreckage revealed no anomalies in the flight controls or drivetrain; all damage was consistent with the impact sequence. The Rolls-Royce Allison 250 C47 engine exhibited external signs of foreign object damage to the radial compressor impeller resulting from the accident. The N1 and N2 shafts rotated freely, there was no oil leakage, and metal particle detectors in the oil system were clean. Notably, unburned fine metal and paint particles were found in the exhaust diffuser, likely originating from structure in the intake area, suggesting that combustion was not occurring in the engine at the moment the airframe broke up after ground contact. The engine was removed for further analysis, and the Full Authority Digital Engine Control (FADEC) unit was preserved for data reading. Investigations conducted by the manufacturer and the National Transportation Safety Board (NTSB) found no evidence of engine malfunction. Spray metal deposits on the power turbine blades indicated the engine was running at ground impact. FADEC data parameters showed normal engine operation leading up to the accident.
Weather Conditions
At the time of the accident, weather conditions were good with light gusty winds from the east-southeast at a mean of 15 knots.
Conclusion
Technical examinations of the wreckage revealed no evidence of a mechanical failure that could have caused the accident. Based on the evidence at the scene and witness statements, a determination of pilot error could not be made. The accident cause could not be determined.