- Date
- May 28, 2016, 16:35 local (21:35 UTC)
- Place
- Spring Branch, TX
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Taxi
- Aircraft
- N921ESRobinson Helicopter R44
- Defining event
- Taxi-into takeoff position: Abrupt maneuver
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 22, 2016
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20160528007919A
- Case key
- 93324
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 helicopter control while hovering in gusting tailwind conditions, resulting in the tailboom striking a light pole and impact with terrain.
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
According to the pilot, he was hover taxiing the helicopter in a confined area, after refueling. He reported there was a large tree to the southwest of his position and a light pole to northeast of his position. He recalled that he began to taxi to the northwest; away from the light pole, but "a significant left quartering wind" about 9 knots gave him "a hard time controlling the tail". He reported that he did not feel that he could turn the nose into the wind in the confined area and decided to climb vertically to avoid obstacles. He reported that he ascended, encountered a wind gust, and the tailboom yawed to the right and struck the light pole. The helicopter descended, impacted the ground, and came to rest on its left side. The helicopter sustained substantial damage to the fuselage, the main and tail rotor systems. The pilot reported that there were not any mechanical anomalies or malfunctions with any portion of the helicopter that would have prevented normal flight operations. The nearest weather reporting station was two miles north-northwest. The meteorological aerodrome report about the time of the accident reported the wind was out of 160 degrees true at 11 knots. FAA-8083-21A, Chap. 11-20 para. 2 states: Weathercock Stability (120–240°) In this region, the helicopter attempts to weathervane, or weathercock, its nose into the relative wind. Unless a resisting pedal input is made, the helicopter starts a slow, uncommanded turn either to the right or left, depending upon the wind direction. If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly. In order to avoid the onset of LTE in this downwind condition, it is imperative to maintain positive control of the yaw rate and devote full attention to flying the helicopter.
Factual narrative
According to the pilot, he was hover taxiing the helicopter in a confined area, after refueling. He reported there was a large tree to the southwest of his position and a light pole to northeast of his position. He recalled that he began to taxi to the northwest; away from the light pole, but "a significant left quartering wind" about 9 knots gave him "a hard time controlling the tail". He reported that he did not feel that he could turn the nose into the wind in the confined area and decided to climb vertically to avoid obstacles. He reported that he ascended, encountered a wind gust, and the tailboom yawed to the right and struck the light pole. The helicopter descended, impacted the ground, and came to rest on its left side. The helicopter sustained substantial damage to the fuselage, the main and tail rotor systems. The pilot reported that there were not any mechanical anomalies or malfunctions with any portion of the helicopter that would have prevented normal flight operations. The nearest weather reporting station was two miles north-northwest. The meteorological aerodrome report about the time of the accident reported the wind was out of 160 degrees true at 11 knots. FAA-8083-21A, Chap. 11-20 para. 2 states: Weathercock Stability (120–240°) In this region, the helicopter attempts to weathervane, or weathercock, its nose into the relative wind. Unless a resisting pedal input is made, the helicopter starts a slow, uncommanded turn either to the right or left, depending upon the wind direction. If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly. In order to avoid the onset of LTE in this downwind condition, it is imperative to maintain positive control of the yaw rate and devote full attention to flying the helicopter.
Aircraft
- Registration
- N921ES
- Reported as
- Robinson Helicopter R44 (Raven II)
- Category
- Helicopter
- Serial number
- 13643
- Built
- 2014
- Airframe hours
- 204.9
- Engine
- Lycoming IO-540-A1A5, 290 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Operator
- Flying Helicopters Inc
- Registered owner
- Flying Helicopters Inc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · January 12, 2016
- Departed
- PVT · Borne, TX
- Destination
- 1T7 · Spring Branch, TX
- Airport
- 1T7 · Kestrel Airpark
- Equipment
- Satellite tracking device, Stall warning system
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
- 69
- Injuries
- None
- Certificates
- Airline transport, Private
- Airplane ratings
- Multi-engine land, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, With waivers/limitations
- Last flight review
- April 3, 2016
- Restraint
- 3-point
- Flight hours
- 4,928 total · 635 in this make and model · 4,750 as pilot in command · 28.7 in the last 90 days · 7.3 in the last 30 days · 3.2 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 160° at 11 knots
- Visibility
- 10 statute miles
- Temperature
- 90 °F, dew point 75 °F
- Altimeter
- 29.90 inHg
- Observed at
- KRND, 2 nm away
Docket · 2
The files NTSB released with the investigation on September 2, 2016, on NTSB’s docket system: statements, records, photos and specialists’ reports. 695 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.