Cessna 207 accident near Quinhagak, Alaska, January 10, 1999
On January 10, 1999 at about 5:30 pm local time, a Cessna 207, registered N6312H, was substantially damaged in an accident near Quinhagak, Alaska (Quinhagak airport). It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Loss of engine power due to fracture of the engine crankshaft, and the manufacturer's improper manufacturing procedure during engine assembly. Factors associated with the accident were the manufacturer's inadequate quality control standards, trees, and snow-covered terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 10, 1999 · about 5:30 pm local time
- Place
- Quinhagak, Alaska · Quinhagak · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 207 · all 207s on the register
- Registration
- N6312H · no longer on the register · serial 20700478
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The certificated commercial pilot reported that during the initial descent to land, the engine began to run rough and lose power. He noted that the roughness improved momentarily, followed by a severe engine vibration, and complete loss of engine power. The pilot selected a forced landing area on snow and tree-covered terrain. The airplane sustained substantial damage to the landing gear, fuselage, and wings. Postaccident investigation discovered that the engine crankshaft had sustained a complete fracture of the #2 cheek. A subsequent investigation revealed that on some crankshafts, a crack in the nitride layer that originated from a shallow tool mark, would in some cases ultimately lead to the fatigue failure of the crankshaft cheek. On April 22, 1999, the FAA issued an emergency airworthiness directive (AD) requiring that all TCM 470, 520, and 550 engine crankshafts manufactured in 1998, with less than 300 hours in service, will be inspected in accordance with the TCM critical service bulletin (CSB) within 10 hours of operation.
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
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane
- Flight time: 5,350 hours in all; 1,100 in this make and model; 238 in the last 90 days; 100 in the last 30 days; 5,230 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 10,286 hours
- Last inspection: 100-hour inspection, December 16, 1998; 75 hours since
- Maximum gross weight: 3,800 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental IO-520-F (piston); 0 hours total
The flight
- Departed from: BET Bethel AK at 4:45 pm
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 040° at 5 knots
- Visibility: 20 statute miles
- Sky: broken clouds at 1,000 ft; not recorded
- Temperature: 16°F (-9°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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 N6312H 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.