Grumman-Schweizer G-164A accident near Prescott, Washington, May 27, 1999
On May 27, 1999 at about 3:00 pm local time, a Grumman-Schweizer G-164A, registered N9970, was substantially damaged in an accident near Prescott, 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 pilot-in-command's failure to maintain directional control during the takeoff roll and overloading of the right landing gear strut. Contributing factors were the soft takeoff surface, confined (narrow) takeoff surface, and high vegetation.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 27, 1999 · about 3:00 pm local time
- Place
- Prescott, Washington · 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
- N9970 · no longer on the register · serial 1375
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
After approximately 900 feet of takeoff roll, the Grumman G-164A 'AgCat' rolled off the left side of the 15 foot wide, soft, sandy airstrip/road and came to rest rotating approximately 200 degrees counter-clockwise from the takeoff heading. There was no evidence of any mechanical malfunction with the aircraft and the left wing spray boom retention arm aft brackets had separated in overload as did the right main landing gear strut. High wheat flanked either side of the landing strip. The operator reported that '[the] left wing and spray boom entered wheat along side of [the] airstrip pulling [the] aircraft off [the] strip and into [the] wheat field. [The] aircraft was unable to recover directional control with rudder.'
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: balloon
- Flight time: 9,500 hours in all; 7,600 in this make and model
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 8,436 hours
- Last inspection: annual inspection, February 17, 1999; 106 hours since
- Maximum gross weight: 6,497 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 37°F (3°C)
- Altimeter: 30.00 inHg
- Observation at 2:53 pm from ALW, 16 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.