Grumman-Schweizer G-164A accident near New Plymouth, Idaho, July 7, 1999
On July 7, 1999 at about 1:30 am local time, a Grumman-Schweizer G-164A, registered N7869, was substantially damaged in an accident near New Plymouth, Idaho. 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
Loss of engine power due to failure of the supercharger impeller. A contributing factor was the ditch.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 7, 1999 · about 1:30 am local time
- Place
- New Plymouth, Idaho · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman-Schweizer G-164A
- Registration
- N7869 · no longer on the register · serial 1003
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
Immediately after takeoff the pilot sensed a loss of engine performance and attempted to return to the departure airstrip. Unable to maintain altitude, he dumped the chemical load and then initiated a forced landing to an agricultural (sugar beet) field. The pilot was unable to stop the aircraft before reaching an irrigation ditch and impacted the upsloping terrain at the ditch's opposite side. Partial disassembly of the engine revealed that a gear tooth from the engine's supercharger blower section had broken off and was found in the blower drive section.
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
- Flight time: 14,000 hours in all; 4,000 in this make and model; 2 in the last 90 days
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 6,227 hours
- Last inspection: annual inspection, May 3, 1999; 45 hours since
- Maximum gross weight: 4,500 lb
- Seats: 0
- Landing gear: fixed
- Engine: P&W R-985-14B (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 350° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 90°F (32°C), dew point 46°F (8°C)
- Altimeter: 29.00 inHg
- Observation at 1:53 am from ONO, 9 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.