- Date
- November 18, 2018, 08:30 local (14:30 UTC)
- Place
- Knox City, TX
- Injuries
- 4 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N4167YRobinson R44
- Defining event
- Maneuvering-low-alt flying: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 26, 2019
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20181118022739A
- Case key
- 98654
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 pilot's failure to maintain adequate airspeed with a tailwind, which resulted in the helicopter settling with power, and his subsequent incorrect collective application while attempting to recover, which resulted in a loss of helicopter control due to a loss of tail rotor effectiveness.
Findings · 5
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 helicopter pilot reported that, while conducting a photography flight about 70 ft above ground level, the helicopter's heading was 190°, and the airspeed was less than 9 knots. With a 10-knot tailwind, the helicopter began to settle with power. The pilot increased the collective and applied forward cyclic to increase the airspeed, but the helicopter continued to settle and impacted the ground hard. The helicopter sustained substantial damage to the main rotor system and fuselage. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot reported that the wind about the time of the accident was from the north at 10 knots. According to the Helicopter Flying Handbook, Chapter 11, page 11-10 When recovering from a settling with power condition, the pilot tends first to try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thereby increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control may be limited. Recovery is accomplished by increasing airspeed, and/or partially lowering collective pitch. In many helicopters, lateral cyclic combined with lateral tailrotor thrust will produce the quickest exit from the hazard assuming that there are no barriers in that direction. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state.
Factual narrative
The helicopter pilot reported that while conducting a photography flight about 70ft AGL, the helicopter's heading was 190° and the airspeed was less than 9 knots. With a 14-knot tailwind the helicopter began to settle with power. He increased collective and applied forward cyclic to increase the airspeed, but the helicopter impacted the ground. The helicopter sustained substantial damage to the main rotor system and the fuselage. The pilot reported that the wind about the time of the accident was from the north at 14 knots. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. According to the Helicopter Flying Handbook, Chapter 11, page 11-10: When recovering from a settling with power condition, the pilot tends first to try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thereby increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control may be limited. Recovery is accomplished by increasing airspeed, and/or partially lowering collective pitch. In many helicopters, lateral cyclic combined with lateral tailrotor thrust will produce the quickest exit from the hazard assuming that there are no barriers in that direction. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state.
Aircraft
- Registration
- N4167Y
- Reported as
- Robinson R44 (Undesignat)
- Category
- Helicopter
- Serial number
- 1889
- Built
- 2008
- Airframe hours
- 2,087.5
- Engine
- Lycoming O-540-F1B5, 235 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial observation · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · July 10, 2018
- Departed
- F75 · Knox City, TX
- Destination
- F75 · Knox City, TX
- Equipment
- None
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
- 34
- Injuries
- None
- Certificate
- Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- September 28, 2018
- Seat
- Right
- Restraint
- 3-point
- Flight hours
- 302.8 total · 302.8 in this make and model · 224.8 as pilot in command · 35.2 in the last 90 days · 30.8 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 350° at 10 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 3,300 ft overcast
- Temperature
- 30 °F, dew point 23 °F
- Altimeter
- 30.37 inHg
- Observed at
- KCDS, 57 nm away
Docket · 2
The files NTSB released with the investigation on June 27, 2019, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.6 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.