- Date
- February 3, 2011, 17:20 local (Feb 4, 2011, 00:20 UTC)
- Place
- Ogden, UT
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Emergency descent
- Aircraft
- N441TBRobinson R44
- Defining event
- Autorotation: Hard landing
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 8, 2011
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- FAA FSDO
- FAA report
- 20110203000739A
- Case key
- 78278
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 certified flight instructor’s failure to maintain adequate main rotor blade rpm during a practice autorotation, resulting in a hard landing and 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
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 at 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’ rpms began decaying rapidly. About 200 feet above ground level the CFI attempted a power recovery, but the rpms did not increase with an increase in throttle. He unsuccessfully attempted to flair to bring the rpms back before attempting a full down autorotation. He put the helicopter in a level attitude prior to contact with the ground and the helicopter bounced upon initial contact; on the second contact, the right skid dug into the muddy ground and the helicopter rolled onto its right side. The helicopter sustained substantial damage to the airframe and rotor blades. The pilots stated that the helicopter had no mechanical failures or malfunctions prior to the accident.
Factual 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.
Aircraft
- Registration
- N441TB
- Reported as
- Robinson R44 (UNDESIGNAT)
- Category
- Helicopter
- Serial number
- 0631
- Airframe hours
- 1,676
- Engine
- Lycoming O-540-F1B5, 250 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Whirlybird Helicopters LLC
- Registered owner
- Av8 LLC
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · January 13, 2011 · 32 hours before
- Departed
- OGD · Ogden, UT
- Destination
- OGD · Ogden, UT
- Flight plan
- Company VFR
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
- 24
- Injuries
- None
- Certificates
- Flight instructor, Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- July 29, 2009
- Seat
- Left
- Flight hours
- 964 total · 661 in this make and model · 806 as pilot in command · 200 in the last 90 days · 55 in the last 30 days
- Role
- Student pilot
- Age
- 30
- Injuries
- None
- Certificate
- Private
- Instrument ratings
- Helicopter
- Medical
- Class 2, Without waivers/limitations
- Seat
- Right
- Flight hours
- 172 total · 109 as pilot in command · 29 in the last 90 days · 10 in the last 30 days · 1 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 25 °F, dew point 7 °F
- Altimeter
- 30.46 inHg
- Observed at
- KOGD
Docket · 1
The files NTSB released with the investigation on March 7, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.8 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.