# NTSB GAA16CA283: Robinson Helicopter R44, N921ES, Spring Branch, TX, May 28, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 28, 2016, 16:35 local (21:35 UTC) - Place: Spring Branch, TX - Coordinates: 29.5025, -98.243888 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.5025&lon=-98.2439&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi-into takeoff position: Abrupt maneuver](https://openairdocs.org/ntsb-events/270) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 22, 2016 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 93324 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA16CA283 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93324/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93324 - Page: https://openairdocs.org/ntsb/GAA16CA283 ## 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 NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Robinson Helicopter R44, 40 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7640120), [All aircraft, 9,308 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Robinson Helicopter R44, 6 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=7640120), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Object/animal/substance: pole](https://openairdocs.org/ntsb-findings/03022010): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Robinson Helicopter R44, 1 case](https://openairdocs.org/ntsb-findings/03022010/cases.md?model=7640120), [All aircraft, 142 cases](https://openairdocs.org/ntsb-findings/03022010/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Robinson Helicopter R44, 5 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=7640120), [All aircraft, 1,201 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) - [Performance/control parameters: yaw control](https://openairdocs.org/ntsb-findings/01062024): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R44, 6 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md?model=7640120), [All aircraft, 150 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi-into takeoff position: Abrupt maneuver](https://openairdocs.org/ntsb-events/270) (defining event); cases with it: [Robinson Helicopter R44, 4 cases](https://openairdocs.org/ntsb-events/270/sequence.md?model=7640120), [All aircraft, 346 cases](https://openairdocs.org/ntsb-events/270/sequence.md) - [Maneuvering-hover: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Robinson Helicopter R44, 3 cases](https://openairdocs.org/ntsb-events/400/sequence.md?model=7640120), [All aircraft, 1,130 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Maneuvering-hover: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Robinson Helicopter R44, 56 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7640120), [All aircraft, 10,154 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## 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](https://openairdocs.org/deregistered/N921ES-2019-04-08), registration cancelled 2019-04-08, S/N 13643, built 2014 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER R44 (Raven II) - Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs) - Registry engine: [Lycoming IO-540-A1A5](https://openairdocs.org/engine/lycoming-io-540-a1a5) (registry code 41634, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 13643 - Year built: 2014 - Airframe hours: 204.9 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 69; injuries: none; 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 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20160528007919A](https://openairdocs.org/incident/20160528007919A), May 28, 2016: Robinson Helicopter R44, Spring Branch, TX, Substantial damage. Helicopter landed at Kestrel airpark Spring Branch , Texas for refuel stop. After refuel, pilot began his taxi for departure on runway 12.while exiting refuel… ## Docket (2 files) The files NTSB released with the investigation on September 2, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93324. 695 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 571 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40444172&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photo (item 2, .PDF, 123 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40444173&FileExtension=.PDF&FileName=Photo-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.