- Date
- September 25, 2012, 18:00 local (Sep 26, 2012, 02:00 UTC)
- Place
- Anchorage, AK
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Emergency descent
- Aircraft
- N4171JRobinson Helicopter R22 Beta II
- Defining event
- Autorotation: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 19, 2012
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- Parties
- Federal Aviation Administration
- FAA report
- 20120925023289A
- Case key
- 85148
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 flight instructor's inadequate supervision of the student pilot during a hovering autorotation, which resulted in a dynamic rollover.
Findings · 3
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The flight instructor was providing primary helicopter flight instruction to a student pilot. The instructor reported that while practicing a series of hovering autorotations, he inadvertently allowed the student pilot to drift to the left during the descent. The instructor then took control of the helicopter, applied right cyclic, and raised the collective slightly to level the helicopter and arrest the descent, but the helicopter started to descend with the right skid low. The instructor then added left cyclic and raised the collective further in an attempt to cushion the landing. The helicopter then drifted to the right as the right skid subsequently struck the ground. After touchdown, the helicopter’s skids slid over the asphalt surface before the right skid “caught,” the helicopter rolled to the right, and the main rotor blades struck the ground. The helicopter came to rest on its right side, sustaining substantial damage to the fuselage, tail boom, and main rotor drive system. The instructor reported that there were no preaccident mechanical problems with the helicopter that would have precluded normal operation. He also stated that the accident might have been avoided if he had taken corrective action sooner and with less input on the cyclic.
Factual narrative
The certificated flight instructor (CFI) was providing primary helicopter flight instruction to a student pilot. The CFI reported that while practicing a series of hovering autorotations, he inadvertently allowed the student pilot to drift to the left during the descent. The CFI then took control of the helicopter, applied right cyclic and raised the collective slightly to level the helicopter and arrest the descent, but the helicopter started to descend with the right skid low. He then added left cyclic, and raised the collective further in an attempt to cushion the landing. The helicopter then drifted to the right as the right skid subsequently struck the ground. After touchdown, the helicopter’s skids slid over the asphalt surface before the right skid “caught” and the helicopter rolled to the right, and the main rotor blades struck the ground. The helicopter came to rest on its right side, sustaining substantial damage to the fuselage, tail boom and main rotor drive system. In his written statement to the NTSB, the pilot reported that there were no preaccident mechanical problems with the helicopter, and in the recommendations section of the NTSB 6120.1 form he reported that the accident might have been avoided if he had taken corrective action sooner, and with less input on the cyclic.
Aircraft
- Registration
- N4171J
- Reported as
- Robinson Helicopter R22 Beta II
- Category
- Helicopter
- Serial number
- 4392
- Airframe hours
- 2,096
- Engine
- Lycoming O-360-J2A, 124 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Alpine Air Alaska Inc
- Registered owner
- Alpine Air Alaska Inc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · September 1, 2012
- Departed
- PAMR · Anchorage, AK
- Destination
- PAMR · Anchorage, AK
- Airport
- PAMR · Merrill Field, runway 05, asphalt
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
- Flight instructor
- Age
- 31
- Injuries
- None
- Certificate
- Flight instructor
- Instrument ratings
- Helicopter
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- December 11, 2011
- Seat
- Right
- Flight hours
- 338 total · 255 in this make and model · 271 as pilot in command · 127 in the last 90 days · 45 in the last 30 days · 2 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- 8,500 ft overcast
- Temperature
- 48 °F, dew point 45 °F
- Altimeter
- 29.30 inHg
- Observed at
- PAMR
Docket · 2
The files NTSB released with the investigation on October 29, 2012, on NTSB’s docket system: statements, records, photos and specialists’ reports. 973 KB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.