Willey Rotorway Exec 90
Westport, OK — March 8, 2008
Event Information
| Date | March 8, 2008 |
| Event Type | ACC |
| NTSB Number | DFW08CA079 |
| Event ID | 20080411X00454 |
| Location | Westport, OK |
| Country | USA |
| Coordinates | 36.22222, -96.34444 |
| Highest Injury | NONE |
Aircraft
| Make | Willey |
| Model | Rotorway Exec 90 |
| Category | HELI |
| FAR Part | 091 |
| Aircraft Damage | SUBS |
Conditions
| Light Condition | DAYL |
| Weather | VMC |
Injuries
| Fatal | 0 |
| Serious | 0 |
| Minor | 0 |
| None | 2 |
| Total Injured | 0 |
Event Location
Probable Cause
An unsuccessful precautionary landing due to an electrical system malfunction.
Full Narrative
The certified flight instructor and the student pilot were on an instructional flight to practice autorotations and simulated engine failures. About 45 minutes into the flight the instructor noticed the engine tachometer read lower than the rotor tachometer. The student pilot checked the battery voltage and said that it was "low". The instructor reported that the engine's fuel pump and ignition systems were not independent and he did not want to risk a downwind autorotation landing. When the instructor saw the rotor tachometer drop to 90 percent, he initiated an autorotation, assuming the helicopter had or was about to lose engine power. During the landing the left skid sank into the soft terrain and the helicopter subsequently rolled on to its side. The helicopter sustained substantial damage during the precautionary landing.
About This NTSB Record
This aviation event was investigated by the National Transportation Safety Board (NTSB). NTSB investigates all U.S. civil aviation accidents to determine probable cause and issue safety recommendations to prevent future accidents.