Schweizer G-164B accident near Oakdale, Washington, June 27, 1998
On June 27, 1998 at about 1:30 pm local time, a Schweizer G-164B, registered N7502C, was substantially damaged in an accident near Oakdale, Washington (Oakesdale airport). 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
A fatigue failure of the number three cylinder exhaust rocker box assembly, compromising the ability of the exhaust valve to operate. Factors include a ditch at the end of the runway.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 27, 1998 · about 1:30 pm local time
- Place
- Oakdale, Washington · Oakesdale · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Schweizer G-164B
- Registration
- N7502C · registry record · serial 817-B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
According to the pilot, during takeoff, approximately 10 feet above the ground, the aircraft started backfiring and losing power. He aborted the takeoff, but was unable to get the aircraft stopped before impacting a ditch just off the departure end of the airstrip. A post-accident inspection of the engine by an FAA Airworthiness Inspector found that a portion of the number three cylinder head casting through which the exhaust valve rocker pin passes had fractured. This allowed the number three cylinder exhaust valve to remain in the closed position during the time that it should have been open, resulting in a loss of power. The rocker box casting was sent to the NTSB metallurgical laboratory for further analysis. That examination revealed that the fracture in the casting was the result of a fatigue crack that originated in the wall of the hole in the casting through which the rocker arm pivot bolt passed. It could not be determined what caused the fatigue crack to initiate.
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; single-engine sea; instrument: airplane
- Flight time: 19,400 hours in all; 600 in this make and model; 200 in the last 90 days
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 4,048 hours
- Last inspection: inspection type not recorded, February 25, 1998; 347 hours since
- Landing gear: fixed
- Engine: P&W 1340 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0, 2,100 ft by 55 ft
Weather at the time
- Light: daylight
- Wind: from 180° at 5 knots
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.