# NTSB GAA18CA117: Hughes Helicopters 369, N618SG, Wrightwood, CA, February 1, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: February 1, 2018, 09:45 local (17:45 UTC) - Place: Wrightwood, CA - Coordinates: 34.208889, -117.40361 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.2089&lon=-117.4036&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report August 27, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 96697 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA117 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96697/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96697 - Page: https://openairdocs.org/ntsb/GAA18CA117 ## Probable cause The pilot’s high altitude, high gross weight landing with insufficient tail rotor thrust resulting in a loss of tail rotor effectiveness. ## 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: [Hughes Helicopters 369E, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=4470707), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Tail rotor](https://openairdocs.org/ntsb-findings/01046400): Aircraft › Aircraft propeller/rotor · Capability exceeded (probable cause); cases with it: [Hughes Helicopters 369E, 1 case](https://openairdocs.org/ntsb-findings/01046400/cases.md?model=4470707), [All aircraft, 23 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md) - [Performance/control parameters: yaw control](https://openairdocs.org/ntsb-findings/01062024): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Hughes Helicopters 369E, 1 case](https://openairdocs.org/ntsb-findings/01062024/cases.md?model=4470707), [All aircraft, 149 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. - [Landing: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242); cases with it: [Hughes Helicopters 369E, 1 case](https://openairdocs.org/ntsb-events/242/sequence.md?model=4470707), [All aircraft, 100 cases](https://openairdocs.org/ntsb-events/242/sequence.md) - [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Hughes Helicopters 369E, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=4470707), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Hughes Helicopters 369E, 3 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=4470707), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot selected a landing site on a ridge above 8,000 ft mean sea level and initiated an approach. The helicopter descended below effective translational lift airspeed, and the pilot turned the nose of the helicopter to the right. The helicopter developed a rapid right yaw, and he applied full left pedal to arrest the yaw and forward cyclic to fly out of the condition, but the main rotor blades struck the ground. The helicopter came to rest on its left side, and sustained substantial damage to the fuselage, the tailboom and both rotor systems. The pilot reported that the maximum gross weight of the helicopter was 3,000 pounds, and the weight of the helicopter at the time of the accident was 2,700 pounds. According to the recommendation section of the National Transportation Safety Board pilot's aircraft accident report, the pilot reported that the accident could have been prevented if the helicopter wasn't so heavy. Additionally, he noted that he should have selected a better landing area with the landing direction into the wind. Per the Federal Aviation Administration Helicopter Flying Handbook pg. 11-20, "Loss of Tail Rotor Effectiveness [LTE]," when operating at high altitudes and high gross weights, especially while hovering, the tail rotor thrust may not be sufficient to maintain directional control, and LTE can occur. In this case, the hovering ceiling is limited by tail rotor thrust and not necessarily power available. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. ## Factual narrative The helicopter pilot selected a landing site on a ridge above 8,000ft mean sea level, and initiated an approach. The helicopter descended below effective translational lift airspeed, and the pilot turned the nose of the helicopter to the right. The helicopter developed a rapid right yaw, and he applied full left pedal to arrest the yaw, and forward cyclic to fly out of the condition, but the main rotor blades struck the ground. The helicopter came to rest on its left side, and sustained substantial damage to the fuselage, the tailboom and both rotor systems. The pilot reported that the maximum gross weight of the helicopter was 3,000 pounds, and the weight of the helicopter at the time of the accident was 2,700 pounds. According to the Recommendation section of the National Transportation Safety Board Pilot's Aircraft Accident Report, the pilot reported that the accident could have been prevented if the helicopter wasn't so heavy. Additionally, he noted that he should have selected a better landing area with the landing direction into the wind. Per the Federal Aviation Administration Helicopter Flying Handbook pg. 11-20, "Loss of Tail Rotor Effectiveness" LTE at Altitude, when operating at high altitudes and high gross weights, especially while hovering, the tail rotor thrust may not be sufficient to maintain directional control, and LTE can occur. In this case, the hovering ceiling is limited by tail rotor thrust and not necessarily power available. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N618SG](https://openairdocs.org/deregistered/N618SG-2020-11-06), registration cancelled 2020-11-06, S/N 0014E, built 1982 (OpenAirDocs) - Reported make and model: HUGHES HELICOPTERS INC 369 (E) - Registry model: [Hughes Helicopters 369E](https://openairdocs.org/model/hughes-helicopters-369e) (registry code 4470707) (OpenAirDocs) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 0014E - Year built: 1982 - Airframe hours: 8250.8 - Engines: Rolls Royce 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Operator: Western Helicopters, Inc., doing business as Western Helicopters, Inc. - Registered owner: Helicopters Unlimited LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 2, 2018 - Departed: RAL, RIVERSIDE, CA - Destination: Wrightwood, CA - Flight plan: Company VFR - Equipment: Handheld GPS, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 75; injuries: none; flight instructor, airline transport, commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review April 24, 2017; seat: left; restraint: 4-point; flight hours: 20,000 total, 7,850 in this make and model, 19,000 as pilot in command, 29 in the last 90 days, 8 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Temperature: 72 °F, dew point 28 °F - Altimeter: 30.04 inHg - Observed at: KCCB, 15 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 20180201001939A](https://openairdocs.org/incident/20180201001939A), Feb 1, 2018: Hughes Helicopters Inc HU-369-E, Wrightwood, CA, Substantial damage. N618SG, a HU369E on a part 135 revenue flight, lost control during its landing approach just prior to touchdown at a 8300 ft MSL mountain landing zone (lz)… ## Docket (2 files) The files NTSB released with the investigation on June 20, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96697. 4.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40464246&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photos (Courtesy of FAA) (item 2, .PDF, 2 photos, 298 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40464247&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.