- Date
- October 14, 2011, 09:20 local (14:20 UTC)
- Place
- Fort Worth, TX
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Standing
- Aircraft
- N10375Hughes 269A
- Defining event
- Standing-engine(s) operating: Ground resonance
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 27, 2011
- Report
- Approved by Office Director
- NTSB office
- Central Region
- Parties
- Federal Aviation Administration
- FAA report
- 20111014028709A
- Case key
- 82113
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 inadvertent entry into ground resonance after a hovering autorotation.
Findings · 2
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 certified flight instructor (CFI) and pilot receiving instruction were practicing hovering autorotations on a taxiway. With the skids on the ground for about 20 seconds after completing a hovering autorotation and with the engine at 2,000 rpm, the helicopter began to vibrate and violently shake, consistent with ground resonance. The vibrations and shaking continued to increase and lasted about 15 to 30 seconds. After the shaking stopped, the CFI shut down the helicopter. A postaccident examination of the helicopter revealed that the tail rotor and gearbox separated, and the fuselage was bent and deformed. No preimpact mechanical malfunctions or failures with the helicopter were noted that would have precluded normal operation.
Factual narrative
After practicing some flight and landing maneuvers, the certified flight instructor and pilot receiving instruction decided to practice some hovering autorotations on a taxiway. With the skids on the ground for approximately 20 seconds after completing a hovering autorotation and the engine at 2,000 RPM, the helicopter began to vibrate and violently shake. The vibrations and shaking continued to increase and lasted approximately 15 to 30 seconds. After the shaking stopped, the certified flight instructor shutdown the helicopter. Postaccident examination of the helicopter revealed the tail rotor and gearbox separated, and the fuselage was bent and deformed. No preimpact mechanical malfunctions or failures with the helicopter were noted that would have precluded normal operation.
Aircraft
- Registration
- N10375
- Reported as
- Hughes 269A
- Category
- Helicopter
- Serial number
- 67-18376
- Airframe hours
- 6,176
- Engine
- Lycoming HIO-360-B1A, 180 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- On File
- Registered owner
- On File
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · August 25, 2011
- Departed
- FTW · Fort Worth, TX
- Destination
- FTW · Fort Worth, TX
- Airport
- FTW · Fort Worth Mecham Intl. Airpor
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
- 40
- Injuries
- None
- Certificates
- Flight instructor, Private, Commercial
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- July 18, 2010
- Seat
- Left
- Flight hours
- 803 total · 98 in this make and model · 732 as pilot in command · 49 in the last 90 days · 15 in the last 30 days
- Role
- Pilot
- Age
- 40
- Injuries
- None
- Certificates
- Airline transport, Flight instructor, Commercial
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 3, With waivers/limitations
- Last flight review
- February 8, 2011
- Seat
- Right
- Flight hours
- 6,377 total · 65 in this make and model · 4,954 as pilot in command · 47 in the last 90 days · 17 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 54 °F, dew point 50 °F
- Altimeter
- 29.97 inHg
Docket · 2
The files NTSB released with the investigation on November 17, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.2 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.