GAA16CA283

NTSB accident investigation · Robinson Helicopter R44 · Spring Branch, TX · May 28, 2016

Accident · No injuriesData collectionFinal report
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.

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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.

Wind: tailwindEnvironmental issues › Conditions/weather/phenomena · Effect on equipmentRobinson Helicopter R44: 6 casesAll aircraft: 594 casesProbable cause
Object/animal/substance: poleEnvironmental issues › Physical environment · Contributed to outcomeRobinson Helicopter R44: 1 caseAll aircraft: 142 cases
Wind: gustsEnvironmental issues › Conditions/weather/phenomena · Effect on operationRobinson Helicopter R44: 5 casesAll aircraft: 1,199 casesProbable cause
Performance/control parameters: yaw controlAircraft › Aircraft oper/perf/capability · Not attained/maintainedRobinson Helicopter R44: 6 casesAll aircraft: 149 casesProbable cause

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.