Hughes 369D accident near Neah Bay, Washington, October 27, 1989
On October 27, 1989 at about 7:30 pm local time, a Hughes 369D (helicopter), registered N9163F, was substantially damaged in an accident near Neah Bay, Washington. It was an other work-use flight under external-load helicopter rules (Part 133). 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
FATIGUE FAILURE OF ALL FOUR ATTACHMENT STUDS OF THE TAILROTOR GEARBOX RESULTING IN SEPARATION OF THE GEAR BOX, AND INADEQUATE MAINTENANCE INSPECTION.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 27, 1989 · about 7:30 pm local time
- Place
- Neah Bay, Washington · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes 369D · all 369Ds on the register
- Registration
- N9163F · no longer on the register · serial 690540D
- Damage
- Substantial damage
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
DURING AN EXTERNAL LOAD OPERATION, THE PILOT HAD JUST RELEASED THE LOAD AND WAS TRANSITIONING TO A CLIMB ATTITUDE WHEN THE TAIL ROTOR GEARBOX SEPARATED FROM THE TAIL BOOM. THE PILOT WAS UNABLE TO MAINTAIN CONTROL AND THE HELICOPTER COLLIDED INTO THE ROUGH TERRAIN. THE GEARBOX WAS METALLURGICALLY EXAMINED, REVEALING THAT ALL FOUR ATTACHMENT STUDS HAD FAILED DUE TO FATIGUE. FURTHER EXAMINATION REVEALED CONTAMINANTS ON THE GEARBOX MOUNTING PADS BETWEEN THE TAIL ROTOR GEARBOX AND THE TAIL BOOM; FRETTING WAS NOTED. AD88-17-09 AND SERVICE INFORMATION NOTICE DN-151/EN-39/FN-28 BOTH MANDATE INITIAL AND RECURRENT INSPECTION (EVERY FLIGHT) OF THE GEARBOX ATTACHMENT AREA.
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; rotorcraft: helicopter
- Flight time: 9,796 hours in all; 3,512 in this make and model; 332 in the last 90 days; 9,505 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 8,187 hours
- Last inspection: annual inspection, May 9, 1989; 96 hours since
- Maximum gross weight: 2,100 lb
- Seats: 4
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
The flight
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 40 statute miles
- Sky: clear
- Temperature: 0°F (-18°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.
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.