- Date
- December 15, 2012, 13:45 local (20:45 UTC)
- Place
- Logan, UT
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Emergency descent
- Aircraft
- N393LERobinson R22
- Defining event
- Autorotation: Loss of lift
- Weather
- Visual (VMC) · Day
- Status
- Completed · report April 3, 2013
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- Federal Aviation Administration
- FAA report
- 20121215027449A
- Case key
- 85819
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 delayed remedial action and inadequate supervision during a practice autorotation, which resulted in a failure to maintain adequate main rotor rpm. Contributing to the accident was the wet landing surface.
Findings · 4
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
During the 180-degree autorotation, the student pilot maintained an airspeed of 65 knots, with rotor rpm in the green. As the student rolled out of the turn about 300 feet above ground level and at 70 knots, the rotor rpm continued to remain in the green. However, before the flare, the rotor rpm began to decay and failed to build as the flare was entered. The flight instructor then took control of the helicopter and immediately rolled on throttle to recover engine power and to maintain rotor rpm, but there was insufficient engine power to recover, and the low rotor rpm light and horn activated. Because power was not available for a full-power-on landing, the flight instructor initiated a full-down autorotation to a taxiway. During the landing, the helicopter skidded across and off the wet taxiway into loose gravel and mud before the left skid dug into the ground, resulting in the helicopter rolling over and coming to rest on its left side. The helicopter sustained substantial damage to its welded frames, firewall, and tail cone. The flight instructor reported no preaccident mechanical or malfunctions or failures with the helicopter or flight controls that would have precluded normal operation.
Factual narrative
During the 180-degree autorotation the student maintained 65 knots with the rotor revolutions per minute (RPM) in the green. As the student rolled out of the turn at about 300 feet above ground level and at 70 knots, the rotor rpm continued to remain in the green. However, prior to the flare the rotor RPM began to decay and failed to build as the flare was entered. The flight instructor then took control of the helicopter and immediately rolled on throttle to recover engine [power] and to maintain [rotor] RPM, but there was insufficient engine power to recover the decayed rotor RPM; this was followed by a low rotor RPM light and horn. As power was not available for a full power on landing, the flight instructor initiated a full down autorotation to a taxiway. During the landing the helicopter skidded across and off the wet taxiway into loose gravel and mud before the left skid dug into the ground. This resulted in the aircraft rolling over and coming to rest on its left side. The helicopter sustained substantial damage to its welded frames, firewall, and tail cone. The flight instructor reported no mechanical malfunctions or failures with the helicopter or flight controls that would have precluded normal operation.
Aircraft
- Registration
- N393LE
- Reported as
- Robinson R22 (BETA)
- Category
- Helicopter
- Serial number
- 4393
- Airframe hours
- 3,007
- Engine
- Lycoming O-360, 145 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Mountain Ridge Helicopters
- Registered owner
- Mountain Ridge Helicopters
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · December 11, 2012 · 27 hours before
- Departed
- LGU · Logan, UT
- Destination
- LGU · Logan, UT
- Airport
- LGU · Logan-Cache Airport, runway 35, 9,010 × 100 ft, 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 · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Flight instructor
- Age
- 23
- Injuries
- None
- Certificate
- Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- July 7, 2011
- Seat
- Left
- Flight hours
- 651 total · 589 in this make and model · 590 as pilot in command · 129 in the last 90 days · 41 in the last 30 days
- Role
- Student pilot
- Age
- 27
- Injuries
- None
- Certificate
- Student
- Medical
- Class 3, Without waivers/limitations
- Seat
- Right
- Flight hours
- 62 total · 62 in this make and model · 7 as pilot in command · 62 in the last 90 days · 26 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- 5,000 ft overcast
- Temperature
- 43 °F, dew point 28 °F
- Altimeter
- 29.79 inHg
- Observed at
- LGU
Docket · 4
The files NTSB released with the investigation on January 16, 2013, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.2 MB 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.
Other investigations on N393LE · 1
Matched to the same aircraft by N-number and date.