What happened
On March 8, 2009, a Bell 206-L4 helicopter, registration N863H, crashed into terrain near Moundridge, Kansas. The aircraft, operated by Hillcrest Aircraft Company, was performing a positioning flight from Searle Field Airport in Ogallala, Nebraska, to Newton City/County Airport in Kansas.
At approximately 14:24 CDT, the helicopter's Sky Connect system transmitted its last position report, indicating it was traveling at 113 knots at an altitude of 1,749 feet mean sea level, roughly 280 feet above ground level. Shortly thereafter, the aircraft impacted the ground in a wheat field. The pilot, the sole occupant of the aircraft, sustained 1 fatal injury.
Nearby residents reported hearing the engine rev to a high RPM twice, followed by two or three loud thumping sounds before the impact.
The investigation
The investigation of the wreckage revealed a debris path over 100 yards long. The wreckage included a damaged right vertical stabilizer, tail rotor gearbox separation, and multiple strikes from both the main rotor blades and the tail rotor. The engine was found at the end of the debris path; examination by technical representatives showed all engine mounts and the spragg clutch housing had fractured due to overload. While the fuel spray nozzle was found at least finger tight without lock wire, no pre-impact anomalies were detected in the engine or airframe.
An examination of the aircraft's annunciator panel showed no evidence that any warning lights, such as the low rotor RPM light, were illuminated at the time of the accident.
Medical examination of the pilot revealed a history of severe obstructive sleep apnea, treated with a CPAP device, which was recovered from the wreckage. Investigators also found nasal swabs used for congestion relief among the pilot's effects. While the pilot's recent medical records indicated effective treatment and no excessive daytime sleepiness, it could not be determined if the pilot had used the CPAP device in the days immediately preceding the flight.
Findings
- The helicopter impacted terrain in a relatively level attitude at high speed.
- Sky Connect data showed fluctuations in altitude during the flight prior to impact.
- No mechanical anomalies were found in the engine or airframe that would have caused the crash.