Hughes OH-6 accident near Valentine, Texas, February 8, 2008
On February 8, 2008 at about 5:15 pm local time, a Hughes OH-6 (helicopter), registered N66372, was substantially damaged in an accident during maneuvering near Valentine, Texas (None airport). It was a public-use flight (federal) under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
Preview. This page is not yet listed for search engines.
The NTSB's probable cause their words, unchanged
The contract mechanic's failure to properly secure the castellated nut that attached the governor lever control rod to the idler bell crank. Contributing to the accident was the lack of maintenance oversight by the operator.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 8, 2008 · about 5:15 pm local time
- Place
- Valentine, Texas · None · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes OH-6 · all OH-6s on the register
- Registration
- N66372 · no longer on the register · serial 67-16595
- Damage
- Substantial damage
- Flight
- Public-use flight (federal) · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot/air interdiction agent was engaged in a United States Custom and Border Patrol (CBP) mission in a single-engine turbine equipped helicopter when the engine stopped producing power and the helicopter descended rapidly from a height of 30-50 feet above the ground. The pilot maintained directional control and made a hard landing in a wash-out. The helicopter remained upright, but the skids were completely spread, the tail rotor blades were damaged, and the fuselage sustained structural damage. Further examination of the engine revealed that a castellated nut used to secure the governor lever control rod to the idler bell crank had come completely loose, and the cotter pin that secured the nut was missing. The engine had been replaced 5.1 hours prior to the accident by a contract maintenance facility. The mechanic stated that during the first engine run-up, he discovered an oil leak on the left side of the engine. As a result, the engine was shut down and the linkages on the left side of the engine were disassembled, including the governor level control rod assembly. During the reassembly, he got distracted by a phone call, which delayed him from completing the repair. As a result, when he returned to complete the repair, he got "tunnel vision" and forgot to install the cotter pin during the reassembly process, which would have kept the castellated nut that secured the attachment bolt for the governor level control rod from loosening. According to CBP, their agency was responsible for the oversight of this maintenance and the helicopter was returned to service in accordance with the military technical manuals. However, there were no established inspection procedures to properly accept an aircraft that had just undergone a major repair. In addition, a review of the OH-6A Technical Manuals revealed that only a standard castellated nut and cotter pin was needed to properly install the governor lever control rod, while the more recent Hughes 500 repair manual and an FAA Airworthiness Directive required a castellated nut with fiber inserts to prevent the nut from backing off.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (total) during maneuvering defining event
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Rotorcraft flight control › (general) › Incorrect use/operation
- cause Aircraft › Aircraft handling/service › Maintenance/inspections › (general) › Incorrect service/maintenance
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 2,014 hours in all; 255 in this make and model; 143 in the last 90 days; 31 in the last 30 days; 873 as pilot in command
- Last flight review: November 1, 2007
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 5,999 hours
- Last inspection: continuous airworthiness programme, January 1, 2008
- Maximum gross weight: 2,700 lb
- Seats: 4
- Landing gear: fixed
- Engine: Rolls-Royce 250-C20B (turboshaft); 0 hours total
The flight
- Departed from: MRF Marfa TX at 3:40 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 54°F (12°C), dew point 48°F (9°C)
- Altimeter: 30.22 inHg
- Observation at 5:15 pm from MRF, 40 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number DFW08TA066.