Bell BH-47G2A accident near Waitsburg, Washington, March 31, 1991
On March 31, 1991 at about 4:15 pm local time, a Bell BH-47G2A (helicopter), registered N38926, was substantially damaged in an accident near Waitsburg, Washington. 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
THE IMPROPER INSTALLATION OF THE MAIN ROTOR MAST NUT AND LOCK WASHER BY MAINTENANCE PERSONNEL WHICH RESULTED IN THE SEPARATION OF THE MAIN ROTOR SYSTEM.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 31, 1991 · about 4:15 pm local time
- Place
- Waitsburg, Washington · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell BH-47G2A
- Registration
- N38926 · no longer on the register · serial NAH 1957-1
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
WHILE THE PILOT WAS LOWERING THE COLLECTIVE PITCH AFTER LANDING TOUCHDOWN, THE MAIN ROTOR SEPARATED FROMT HE MAST. THE EXAMINATION REVEALED THE IMPROPER INSTALLATION OF THE MAST NUT AND LOCK WASHER WHEN THE MAIN ROTOR WAS INSTALLED.
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: rotorcraft: helicopter
- Flight time: 8,000 hours in all; 8,000 in this make and model; 150 in the last 90 days; 40 in the last 30 days; 8,000 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming VO-435A1F (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 340° at 5 knots
- Visibility: 50 statute miles
- Sky: scat at 18,000 ft
- Temperature: 46°F (8°C), dew point 39°F (4°C)
- Altimeter: 30.00 inHg
- Observation at 3:45 pm from PSC, 37 miles away
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 N38926 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.