Stinson 108-1 accident near Concrete, Washington, October 23, 2008
On October 23, 2008 at about 5:05 am local time, a Stinson 108-1, registered N97946, was substantially damaged in an accident during initial climb near Concrete, Washington (Concrete Municipal airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed and 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of engine power during initial climb due to the pilot's improper exhaust system maintenance, which resulted in restriction of the carburetor's air intake.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 23, 2008 · about 5:05 am local time
- Place
- Concrete, Washington · Concrete Municipal · map
- Type
- Accident
- Injuries
- 1 person was killed and 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Stinson 108-1 · all 108-1s on the register
- Registration
- N97946 · no longer on the register · serial 108-946
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
For 7 years, the pilot had performed maintenance, which included 100-hour and annual inspections of his airplane's engine. On an undetermined date, a rope-like material had been placed between the exhaust's heater shroud and muffler. At an undetermined date/time, this material became separated from its installed location. During takeoff on the accident flight, the rope-like material became lodged in the carburetor's air intake. This resulted in restricting the flow of air into the carburetor, and the engine lost power. It was a dark night, and the airplane collided with trees during the ensuing forced landing. Toxicology results were consistent with the relatively recent use of diphenhydramine, an over-the-counter antihistamine with sedative and impairing effects, and propoxyphene, a prescription narcotic medication with impairing effects. The levels detected on toxicology evaluation were not consistent with impairment at the time of the accident. The pilot had indicated to the FAA a history of diabetes and kidney stones, but not the use of diphenhydramine or propoxyphene, and it could not be determined whether medical conditions or the use of medication may have played a role in his decision to insert the rope-like material in the engine compartment.
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
What happened, in order
- Miscellaneous/other during initial climb
- Aircraft maintenance event during prior to flight
- Loss of engine power (partial) during initial climb defining event
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft power plant › Power plant › (general) › Failure
- cause Aircraft › Aircraft power plant › Engine exhaust › (general) › Incorrect service/maintenance
- cause Personnel issues › Task performance › Maintenance › (general) › Pilot
- Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Contributed to outcome
- Environmental issues › Conditions/weather/phenomena › Light condition › (general) › Contributed to outcome
Pilot
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; multi-engine sea; single-engine land; instrument: airplane
- Flight time: 34,100 hours in all; 113 in this make and model
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Last inspection: annual inspection, August 2, 2008
- Maximum gross weight: 2,100 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin 6A4-150-B3 (piston); 0 hours total
The flight
- Departed from: 3W5 Concrete WA at 5:00 am
- Destination: S50 Auburn WA
- Flight plan: none
- Runway 25, 2,609 ft by 60 ft
Weather at the time
- Light: night, dark
- Wind: from 170° at 8 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 50°F (10°C), dew point 43°F (6°C)
- Altimeter: 30.14 inHg
- Observation at 4:53 am from BLI, 31 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 |
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.