# NTSB GAA16CA296: Robinson Helicopter R22, N931SH, Cahokia/St. Louis, IL, June 7, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 7, 2016, 13:28 local (18:28 UTC) - Place: Cahokia/St. Louis, IL - Coordinates: 38.570278, -90.154998 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.5703&lon=-90.1550&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 27, 2016 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 93350 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA16CA296 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93350/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93350 - Page: https://openairdocs.org/ntsb/GAA16CA296 ## Probable cause The flight instructor's delayed remedial action and his failure to remain vigilant as the helicopter entered the weathercock stability region, in gusting wind conditions, resulting in loss of tail rotor effectiveness and ground impact. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Robinson Helicopter R22 BETA, 35 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=7640110), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md) - [Attention/monitoring: task monitoring/vigilance](https://openairdocs.org/ntsb-findings/02021520): Personnel issues › Psychological · Instructor/check pilot (probable cause); cases with it: [Robinson Helicopter R22 BETA, 11 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md?model=7640110), [All aircraft, 330 cases](https://openairdocs.org/ntsb-findings/02021520/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 R22 BETA, 37 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=7640110), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/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 R22 BETA, 13 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=7640110), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) - [Terrain](https://openairdocs.org/ntsb-findings/03021000): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Robinson Helicopter R22 BETA, 1 case](https://openairdocs.org/ntsb-findings/03021000/cases.md?model=7640110), [All aircraft, 267 cases](https://openairdocs.org/ntsb-findings/03021000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) (defining event); cases with it: [Robinson Helicopter R22 BETA, 10 cases](https://openairdocs.org/ntsb-events/242/sequence.md?model=7640110), [All aircraft, 100 cases](https://openairdocs.org/ntsb-events/242/sequence.md) - [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Robinson Helicopter R22 BETA, 67 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7640110), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-hover: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Robinson Helicopter R22 BETA, 85 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7640110), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis According to the flight instructor, he was instructing his student in hovering flight operations. He reported that he instructed the student to execute a right pedal turn at a three foot hover. The instructor recalled that the student complied and during the turn, as the tail came into the wind, the helicopter started to weathervane, and the turn rate increased rapidly and did not subside until the helicopter impacted the ground. The helicopter sustained substantial damage to the fuselage and both rotor systems. The instructor reported that there were no mechanical anomalies or malfunctions with any portion of the helicopter that would prevent normal flight operations. The instructor reported that the wind velocity at the time of the accident was 11 knots gusting to 16 knots. Weathercock stability is defined as a region of loss of tail rotor effectiveness (120 degree - 240 degree tailwind) that will weathervane the helicopter, and if not prevented will result in a loss of helicopter control about the horizontal axis. According to the Helicopter Flying Handbook (FAA 8083-21A): Pilots who put themselves in situations where the combinations above occur should know that they are likely to encounter LTE. The key is to not put the helicopter in a compromising condition but if it does happen being educated enough to recognize the onset of LTE and be prepared to quickly react to it before the helicopter cannot be controlled. ## Factual narrative According to the flight instructor, he was instructing his student in hovering flight operations. He reported that he instructed the student to execute a right pedal turn at a three foot hover. The instructor recalled that the student complied and during the turn, as the tail came into the wind, the helicopter started to weathervane, and the turn rate increased rapidly and did not subside until the helicopter impacted the ground. The helicopter sustained substantial damage to the fuselage and both rotor systems. The instructor reported that there were no mechanical anomalies or malfunctions with any portion of the helicopter that would prevent normal flight operations. The instructor reported that the wind velocity at the time of the accident was 11 knots gusting to 16 knots. Weathercock stability is defined as a region of loss of tail rotor effectiveness (120 degree - 240 degree tailwind) that will weathervane the helicopter, and if not prevented will result in a loss of helicopter control about the horizontal axis. According to the Helicopter Flying Handbook (FAA 8083-21A): Pilots who put themselves in situations where the combinations above occur should know that they are likely to encounter LTE. The key is to not put the helicopter in a compromising condition but if it does happen being educated enough to recognize the onset of LTE and be prepared to quickly react to it before the helicopter cannot be controlled. ## Aircraft - Registration: [N931SH](https://openairdocs.org/aircraft/N931SH), registered now, S/N 3890, built 2005 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER R22 (BETA) - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series) (registry code 41575, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 3890 - Year built: 2005 - Airframe hours: 5869.2 - Engines: LYCOMING O-360-J2A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: My Sky LLC - Registered owner: My Sky LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 1, 2016 - Departed: CPS, Cahokia/St. Louis, MO - Destination: CPS, Cahokia/St. Louis, MO - Airport: CPS, St Louis Downtown - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 29; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review November 10, 2015; seat: left; restraint: 3-point; flight hours: 289 total, 143 in this make and model, 219 as pilot in command, 26 in the last 90 days, 22 in the last 30 days, 3 in the last 24 hours - Student pilot; age 29; injuries: none; medical: class 2, without waivers/limitations; seat: right; restraint: 3-point; flight hours: 11 total, 11 in this make and model, 11 in the last 90 days, 11 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 7 knots - Visibility: 10 statute miles - Temperature: 79 °F, dew point 46 °F - Altimeter: 29.90 inHg - Observed at: KCPS ## 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 20160607006609A](https://openairdocs.org/incident/20160607006609A), Jun 7, 2016: Robinson Helicopter R22 BETA, Cahokia, IL, Destroyed. Certified flight instructor and student were conducting a training flight practicing hover work in a grass area at the north end of runway 23 at St Louis… ## Docket (2 files) The files NTSB released with the investigation on September 23, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93350. 2.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40444689&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photos (Courtesy of FAA) (item 2, .PDF, 2 photos, 811 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40444690&FileExtension=.PDF&FileName=Photos%20(Courtesy%20of%20FAA)-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.