# NTSB FTW97TA162: Hughes OH-6A, N6638P, Marfa, TX, April 15, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: April 14, 1997, 21:00 local (Apr 15, 1997, 02:00 UTC) - Place: Marfa, TX - Coordinates: 30.310188, -104.02008 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.3102&lon=-104.0201&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 30, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20379 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97TA162 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20379/pdf - Page: https://openairdocs.org/ntsb/FTW97TA162 ## Probable cause the pilot's improper touchdown, and the designated examiner's inadequate supervision. The light condition at dusk was a related factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - flare/touchdown - light condition - dusk (contributing factor) - autorotation - initiated, pilot in command - touchdown - improper, pilot in command (cause) - supervision - inadequate, designated examiner (cause) ## Analysis The instructor pilot, an FAA designated flight examiner, was giving a 'semi-annual helicopter checkride' to a commercial pilot. According to the examiner, the flight was planned for a 'before dark departure...for a more gradual dark adaptation for planned PM full touchdown autorotations.' The commercial pilot performed 'several hovering autorotations and a Run-On landing before complete sunset.' The commercial pilot's first practice autorotation was initiated at dusk from approximately 700 feet AGL, and all indications were 'normal.' At about 65 feet, he initiated a flare and 'held the flare to an approximate altitude of 10 feet, where he began the initial pitch pull and began to level the aircraft.' The helicopter touched down prior to reaching a 'full level attitude and prior to applying full up collective.' The helicopter 'made initial contact on the rear portion of the skids causing the main rotor blades to flex down and sever the tailboom' approximately 2-1/2 feet forward of the tail rotor gearbox. ## Factual narrative On April 14, 1997, approximately 2100 central daylight time, a Hughes OH-6A helicopter, N6638P, registered to and operated by the U.S. Border Patrol as a public use aircraft, was substantially damaged during a practice night touchdown autorotation in Marfa, Texas. Neither the certificated designated examiner pilot nor the commercial pilot-in-command receiving instruction were injured. Visual meteorological conditions prevailed for the night check ride conducted under Title 14 CFR Part 91. A flight plan was not filed for the local flight that originated at Marfa Municipal Airport, Marfa, Texas at 2030. The instructor pilot, a FAA designated flight examiner, was giving a "semi-annual helicopter checkride" to the commercial pilot. According to the instructor, the flight was planned for a "before dark departure... for a more gradual dark adaptation for planned PM full touchdown autorotations." The commercial pilot performed "several hovering autorotations and a Run-On landing before complete sunset." The commercial pilot's first practice autorotation was initiated from approximately 700 feet AGL, during dusk light conditions, and all indications were "normal." At 65 feet, he initiated a flare and "held the flare to an approximate altitude of 10 feet, where he began the initial pitch pull and began to level the aircraft." The aircraft touched down prior to reaching a "full level attitude and prior to applying full up collective." The helicopter "made initial contact on the rear portion of the skids causing the main rotor blades to flex down and sever the tailboom" approximately 2 1/2 feet forward of the tail rotor gearbox. ## Aircraft - Registration: [N6638P](https://openairdocs.org/aircraft/N6638P), registered now, S/N 67-16333 (OpenAirDocs) - Reported make and model: Hughes OH-6A - Registry model: [Hughes OH-6A](https://openairdocs.org/model/hughes-oh-6a) (registry code 4470905) (OpenAirDocs) - Category: Helicopter - Serial number: 67-16333 - Airframe hours: 6338 - Engines: Allison T63A700 300 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Registered owner: U S Border Patrol I&Ns - Airworthiness certificate: Standard, Normal - Last inspection: Unknown, April 1, 1997, 5 hours before - Departed: MRF - Airport: MRF, Marfa Municipal, runway 12, 6,220 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; airline transport; airplane ratings: single-engine sea, multi-engine land, multi-engine sea, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 20,702 total, 2,150 in this make and model, 20,702 as pilot in command, 102 in the last 90 days, 23 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 120° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 48 °F - Altimeter: 30.00 inHg ## 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 19970414037699A](https://openairdocs.org/incident/19970414037699A), Apr 14, 1997: Hughes OH6A, Marfa, TX, Substantial damage. Night practice autorotation. Night recurrent training. Rocked back on skids. Student used aft cyclic. Chopped tail. 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.