Bell 47G-3B2 accident near Yuma, Arizona, September 10, 1995
On September 10, 1995 at about 4:20 pm local time, a Bell 47G-3B2 (helicopter), registered N7942J, was substantially damaged in an accident near Yuma, Arizona. 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 failure of the pilot and company maintenance personnel to detect a crack in the clevis ears during the required daily inspection and the recent annual inspection. A factor in the accident was the improper welding and stress relief procedure used to assemble the components, which induced high residual stresses in the clevis ears and led to fatigue cracking of the part.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 10, 1995 · about 4:20 pm local time
- Place
- Yuma, Arizona · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-3B2 · all 47G-3B2s on the register
- Registration
- N7942J · no longer on the register · serial 6804
- 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 said he was en route to spray a field at 150 feet agl when he heard a loud bang, and a fluttering vibration began through the airframe. The helicopter did not respond to anti-torque control inputs and began to spin. The pilot lowered the collective and reduced throttle to control the spin and the helicopter landed hard. The aft left engine mount frame was found separated from the fuselage frame attachment clevis ears. The clevis ears were found fractured. The engine was displaced forward and to the right and was impinging on the collective servo. The tail rotor short shaft was pulled out and disconnected. The components were sent for metallurgical examination. The clevis ear fractures revealed features indicative of fatigue cracking emanating from multiple origins on the forward and aft faces. The fractures exhibited severe oxidation damage with rust colored deposits evident externally. The metal in the frame and clevis ears was correct for the material specification in the manufacturing drawings. During assembly a washer is welded circumferentially around the outside diameter to the inboard side of each clevis ear. Microhardness testing of the welds, heat affected zones (HAZ), and the base metal of the clevis ears and corresponding washers revealed that the tensile strength of the HAZ adjacent to the fracture of the forward clevis ear was significantly higher than the strength of the weld and the base metal. An annual inspection was accomplished on the helicopter 77 hours prior to the accident and the area of the cracks are the subject of a daily inspection requirement.
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; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 16,000 hours in all; 8,600 in this make and model; 170 in the last 90 days; 60 in the last 30 days; 15,460 as pilot in command; 1,450 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: annual inspection, June 20, 1995; 100 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435-61 (piston); 0 hours total
The flight
- Departed from: YUM at 3:50 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: scat at 15,000 ft
- Temperature: 88°F (31°C), dew point 48°F (9°C)
- Altimeter: 29.00 inHg
- Observation at 3:56 pm from YUM, 18 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.
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.