Hiller UH-12E accident near Quinton, Oklahoma, April 7, 2008
On April 7, 2008 at about 5:30 pm local time, a Hiller UH-12E (helicopter), registered N34SD, was substantially damaged in an accident during enroute (cruise) near Quinton, Oklahoma. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An undetermined mechanical malfuction associated with the tail rotor drive system which led to a loss of control.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 7, 2008 · about 5:30 pm local time
- Place
- Quinton, Oklahoma · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N34SD · registry record · serial 1618
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported hearing a loud noise and experiencing vibrations while piloting his helicopter in cruise about 1,000 feet above the ground. The pilot performed an autorotation to an open field, and was able to maintain control of the helicopter throughout the autorotaion. The pilot reported that a tail rotor strike did not occur. Failed parts from the transmission, tail rotor blades, and associated tail rotor drive hardware were submitted to the NTSB for metallurgical examination. All parts appeared to have failed in overload; however, the origin of the overload failures, or whether they were pre- or post-impact, could not be determined
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
- Sys/Comp malf/fail (non-power) during enroute (cruise) defining event
- Loss of tail rotor effectiveness during enroute (cruise)
- Autorotation Off-field or emergency landing
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › Tail rotor gearbox › Failure
Pilot
- Certificate: airline transport pilot, flight instructor, flight engineer
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: glider; instructor: instrument airplane; instrument: airplane; rotorcraft: glider; rotorcraft: helicopter
- Flight time: 33,000 hours in all; 30 in this make and model
- Last flight review: November 1, 2007
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 4,068 hours
- Last inspection: annual inspection, December 1, 2007
- Maximum gross weight: 2,800 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
The flight
- Departed from: Quinton OK
- Flight plan: none
- Runway NA
Weather at the time
- Wind: from 110° at 11 knots, gusting 14
- Visibility: 10 statute miles
- Sky: broken clouds at 6,000 ft; clear
- Temperature: 75°F (24°C), dew point 50°F (10°C)
- Altimeter: 29.93 inHg
- Observation at 12:53 pm from MLC
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.
Other NTSB records under N34SD the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.