# NTSB GAA19CA063: Robinson R44, N4167Y, Knox City, TX, November 18, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 18, 2018, 08:30 local (14:30 UTC) - Place: Knox City, TX - Coordinates: 33.514999, -99.953613 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.5150&lon=-99.9536&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report September 26, 2019 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 98654 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA063 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98654/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98654 - Page: https://openairdocs.org/ntsb/GAA19CA063 ## 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 NTSB's coded findings; those marked are part of the probable cause. - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Robinson Helicopter R44, 8 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=7640120), [All aircraft, 1,387 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [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) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R44, 3 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=7640120), [All aircraft, 1,682 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R44, 15 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=7640120), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on operation; 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) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Settling with power/vortex ring state](https://openairdocs.org/ntsb-events/244); cases with it: [Robinson Helicopter R44, 1 case](https://openairdocs.org/ntsb-events/244/sequence.md?model=7640120), [All aircraft, 52 cases](https://openairdocs.org/ntsb-events/244/sequence.md) - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Robinson Helicopter R44, 43 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7640120), [All aircraft, 5,010 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-low-alt flying: 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 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](https://openairdocs.org/deregistered/N4167Y-2021-12-04), registration cancelled 2021-12-04, S/N 1889, built 2008 (OpenAirDocs) - Reported make and model: Robinson R44 (Undesignat) - Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs) - Registry engine: [Lycoming O-540-F1B5](https://openairdocs.org/engine/lycoming-o-540-f1b5) (registry code 42353, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 1889 - Year built: 2008 - Airframe hours: 2087.5 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; injuries: none; 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 ## 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 20181118022739A](https://openairdocs.org/incident/20181118022739A), Nov 18, 2018: Robinson Helicopter R44, Knox City, TX, Destroyed. On November 18, 2018, at approximately 0855 central daylight time (CDT), N4167Y, a Robinson R-44 was conducting aerial filming of hog hunting approximately 5… ## Docket (2 files) The files NTSB released with the investigation on June 27, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98654. 3.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40473833&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photo (item 2, .PDF, 142 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40473834&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.