Bell 47G-2 accident near Zillah, Washington, June 12, 1986
On June 12, 1986 at about 11:45 am local time, a Bell 47G-2 (helicopter), registered N11VH, was destroyed in an accident near Zillah, 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 NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 12, 1986 · about 11:45 am local time
- Place
- Zillah, Washington · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-2 · all 47G-2s on the register
- Registration
- N11VH · registry record · serial 2027
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
EN ROUTE TO THE LOCAL SPRAY AREA A TOTAL LOSS OF POWER OCCURRED ALONG WITH A LOSS OF OIL PRESSURE. THE ACFT WAS APRX 200 FT AGL OVER A PEAR ORCHARD. THE PLT WAS ATTEMPTING TO AUTOROTATE ONTO A NEARBY ROAD BUT THE LEFT SKID CAUGHT THE ROOF TOP OF A METAL SHED. THE HELICOPTER CRASHED THROUGH THE ROOF OF THE SHED AND ROLLED OVER ONTO ITS SIDE. INVESTIGATION REVEALED THAT THE NUMBER THREE CYLINDER ROD BOLT HAD FAILED. METALLURGICAL EXAM REVEALED THAT THE NUMBER 3 CYLINDER CONNECTING ROD CAP HAD FAILED AS A RESULT OF OVERSTRESS FORCES DUE TO EXCESSIVE HEATING OF THE ROD AND CAP. FAILURE OF THE NUMBER 3 CYLINDER CONNECTING ROD BOLT WAS DUE TO FATIGUE CRACKING. THE MOST LIKELY CAUSE OF THE OVERHEATING WAS DUE TO A DETERIORATED BEARING.
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: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 2,086 hours in all; 800 in this make and model; 85 in the last 90 days; 1,894 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 9,124 hours
- Last inspection: 100-hour inspection, January 22, 1986; 82 hours since
- Maximum gross weight: 2,450 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435-BIA (piston); 0 hours total
The flight
- Departed from: Buena WA at 11:30 am
- Flight plan: none
- Runway 0
Weather at the time
- Light: dawn
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 64°F (18°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
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 N11VH 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.