ROBINSON R44
Ogden, UT — February 4, 2011
Event Information
| Date | February 4, 2011 |
| Event Type | ACC |
| NTSB Number | WPR11CA121 |
| Event ID | 20110203X11204 |
| Location | Ogden, UT |
| Country | USA |
| Coordinates | 41.35222, -112.19417 |
| Highest Injury | NONE |
Aircraft
| Make | ROBINSON |
| Model | R44 |
| 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
The certified flight instructor’s failure to maintain adequate main rotor blade rpm during a practice autorotation, resulting in a hard landing and rollover.
Full Narrative
After completing several practice landings and autorotations at the airport, the Certified Flight Instructor (CFI) and student pilot departed for the practice area. The CFI demonstrated straight in and 180-degree autorotations; the first 180-degree attempt began at 6,000 feet mean sea level and 55-60 knots. During the second 180-degree attempt, he started about 200 feet lower. The airspeed bled off to about 50 knots during the turn, and the main rotor blades’ revolutions per minute (rpm) began decaying rapidly. About 200 feet above ground level (agl), the CFI attempted a power recovery, but the rpm did not increase with an increase in throttle. He attempted to flair to bring the rpm back, but this did not work either. He attempted a full down autorotation, and put the helicopter in a level attitude prior to contact with the ground. The helicopter bounced; on the second contact, the right skid dug into the muddy ground, and rolled onto its right side. The pilots were not injured, and extricated themselves from the wreckage. The helicopter sustained substantial damage to the airframe and rotor blades. The pilots stated that the helicopter had no mechanical failures or malfunctions.
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.