Cessna 337D accident near Hickory, Pennsylvania, April 1, 1997
On April 1, 1997 at about 7:52 pm local time, a Cessna 337D, registered N2685S, was destroyed in an accident near Hickory, Pennsylvania. It was a business flight under general aviation rules (Part 91). 1 person was killed and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Servicing of the pilots portable oxygen system with compressed air, which resulted in pilot incapacitation due to Hypoxia.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 1, 1997 · about 7:52 pm local time
- Place
- Hickory, Pennsylvania · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 337D · all 337Ds on the register
- Registration
- N2685S · no longer on the register · serial 337-0985
- Damage
- Destroyed
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the unpressurized airplane was cleared to climb to 25,000 feet by air traffic control (ATC) and he was observed going through the assigned altitude and leveling at 27,700 feet. Then the aircraft was observed at 26,000 feet, and subsequent contact was lost. The pilot did not respond when ATC queried him about exceeding his assigned altitude. The aircraft sustained an inflight breakup during an uncontrolled descent, and came to rest in a tree. According to the surviving passenger, the airplane was refueled and a portable oxygen bottle was filled prior to takeoff. She stated that they were going to take aerial photographs at four separate locations during this flight. She said that they shot three of the locations and landed at Williamsburg, Pennsylvania where the pilot filed a flight plan and setup the portable oxygen system for their use during the next flight. They departed and climbed to 10,000 feet, and the pilot told her to put her oxygen mask on, and he did the same. The last altitude she remembered the pilot calling out was 20,000 feet, and he asked her how she was doing and if she felt okay and she said yes. When asked, 'who turned on the oxygen?' she stated that she did, started to but wasn't sure how, so, the pilot reached back and turned it on. She said she knew it was on because she could feel the cool air and that there was a little valve in both lines and they went from red to green indicating the oxygen was flowing. She said that she remembered him saying that they had just crossed 20,000 feet and she began feeling dizzy, she said that her eyes would not focus, and that she felt like she was cross eyed. She said she told the pilot that she was dizzy but she thought that he was talking to the tower because he did not respond. She recalled that she felt better when she closed her eyes, when she did, that was the last thing she clearly remembered until after the crash. Analytical testing of the contents of each cylinder used to fill the pilot's oxygen bottle found that they contained compressed breathing air at about 21 percent oxygen instead of aviation oxygen. Postmortem examination revealed the pilot's death was a result of hypoxic hypoxia due to insufficient oxygen reaching the blood.
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
- Flight time: 3,100 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: annual inspection, October 18, 1996
- Maximum gross weight: 4,500 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental IO-360 (piston); 0 hours total
- Operator: Flight Services, INC.
The flight
- Departed from: WAY Waynesburg PA at 6:45 pm
- Destination: 4G4 North Lima OH
- Flight plan: IFR
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 350° at 13 knots, gusting 23
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 52°F (11°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 7:51 pm from PIT, 65 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.