Cessna T-337 G-P accident near Snoqualmie Pass, Washington, July 17, 1999
On July 17, 1999 at about 8:00 pm local time, a Cessna T-337 G-P, registered N98C, was destroyed in an accident near Snoqualmie Pass, Washington. It was a personal flight under general aviation rules (Part 91). 2 people were killed. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance from mountainous terrain while maneuvering below low ceilings. Factors include low ceilings and inadequate in-flight planning.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 17, 1999 · about 8:00 pm local time
- Place
- Snoqualmie Pass, Washington · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Cessna T-337 G-P · all T-337 G-Ps on the register
- Registration
- N98C · no longer on the register · serial P3370135
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While en route from Lewistown, Montana, to Olympia, Washington, on an instrument flight plan, the pilot developed a problem with the aircraft's autopilot and elected to cancel his instrument flight plan and proceed to Seattle, Washington, where repairs to the aircraft could be made. The pilot stated he was going to continue on his IFR flight plan until reaching Ellensburg, Washington, and then '...change to VFR and drop down and fly through the pass.' Approximately 30 minutes after the pilot canceled his IFR flight plan, a witness observed an aircraft 'with two tail fins' fly out of the clouds and proceed westbound along the Interstate Highway. The witness, who did not see the crash, also stated that the visibility was 100-300 feet, and the clouds were low to the ground. The aircraft collided with mountainous terrain approximately 25 miles east of Seattle, Washington.
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: private
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 2,900 hours in all
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,025 hours
- Last inspection: annual inspection, July 12, 1999
- Maximum gross weight: 4,700 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental TSIO-360-C (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: LWT Lewistown MT at 4:31 pm
- Destination: BFI Seattle WA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 280° at 8 knots
- Visibility: 4 statute miles
- Sky: overcast at 100 ft; not recorded
- Temperature: 43°F (6°C), dew point 43°F (6°C)
- Altimeter: 30.00 inHg
- Observation at 7:56 pm from SMP, 9 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.