- Date
- April 28, 2007, 12:52 local (16:52 UTC)
- Place
- Kalamazoo, MI
- Injuries
- 2 uninjured
- Damage
- Destroyed
- Phase of flight
- Maneuvering
- Aircraft
- N52988Wilkinson Daniel V Rotorway Exec 90
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 27, 2007
- Report
- Approved by Office Director
- FAA report
- 20070428009159A
- Case key
- 65840
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The failure of the sprag clutch which resulted in the disengagement of the drive unit and the pilot's misjudged landing during the autorotation. A factor was the low altitude at which the failure occurred.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The helicopter was destroyed by impact forces and a post crash fire while attempting an auto-rotation after a mechanical failure. The pilot stated that he was practicing takeoffs, hovering, and quick stops above the runway. After takeoff, at about 50 feet and 50mph, he lowered the collective to initiate a quick stop. At this point the engine RPM revved up out of control. He pulled up on the collective to re-engage the drive system, but the system would not engage. He entered into an auto-rotation, and as he neared the ground the helicopter began to slide sideways, folding the skids under the helicopter. The helicopter then rolled on its side, and the occupants climbed out prior to the post crash fire. Subsequent examination of the helicopter's drive system revealed that the drive shafts, pulleys, and drive belts were intact. The only device within the helicopter drive system that could not be determined to be in working condition was the sprag clutch which transmits engine power to the rotor drive system. The sprag clutch was not examined during the course of the investigation.
Factual narrative
The helicopter was destroyed by impact forces and a post crash fire while attempting an auto-rotation after a mechanical failure. The pilot stated that he was practicing takeoffs, hovering, and quick stops above the runway. After takeoff, at about 50 feet and 50mph, he lowered the collective to initiate a quick stop. At this point the engine RPM revved up out of control. He pulled up on the collective to re-engage the drive system, but the system would not engage. He entered into an auto-rotation, and as he neared the ground the helicopter began to slide sideways, folding the skids under the helicopter. The helicopter then rolled on its side, and the occupants climbed out prior to the post crash fire. Subsequent examination of the helicopter's drive system revealed that the drive shafts, pulleys, and drive belts were intact. The only device within the helicopter drive system that could not be determined to be in working condition was the sprag clutch which transmits engine power to the rotor drive system. The sprag clutch was not examined during the course of the investigation.
Aircraft
- Registration
- N52988
- Reported as
- Wilkinson Daniel V Rotorway Exec 90
- Category
- Helicopter, amateur-built
- Serial number
- 1
- Engine
- Rotorway RI-162, 150 horsepower, reciprocating
- Damage
- Destroyed
- Fire
- On-Ground
- Flight
- Personal · Part 91
- Airworthiness certificate
- Special, Experimental (Special)
- Departed
- 4N0 · Kalamazoo, MI
- Airport
- PVT, runway 18, 2,697 × 125 ft, grass/turf
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 59
- Injuries
- Minor
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, With waivers/limitations
- Flight hours
- 463 total · 433 in this make and model · 2 in the last 90 days
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 63 °F, dew point 46 °F
- Altimeter
- 29.87 inHg
- Observed at
- KAZO, 9 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.