FTW97TA162

NTSB accident investigation · Hughes OH-6A · Marfa, TX · April 15, 1997

Accident · No injuriesFinal report
Date
April 14, 1997, 21:00 local (Apr 15, 1997, 02:00 UTC)
Place
Marfa, TX
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N6638PHughes OH-6A
Weather
Visual (VMC) · Dusk
Status
Completed · report January 30, 1998
Report
Approved by Office Director
FAA report
19970414037699A
Case key
20379

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Hard landingLanding - flare/touchdown
Light condition - duskFactor
Autorotation - initiatedPilot in command
Touchdown - improperPilot in commandCause
Supervision - inadequateDesignated examinerCause

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
Reported as
Hughes OH-6A
Category
Helicopter
Serial number
67-16333
Airframe hours
6,338
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
54
Certificate
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.