Helio H-391B accident near Edmonds, Washington, August 26, 1992
On August 26, 1992 at about 3:40 am local time, a Helio H-391B, registered N4431U, was destroyed in an accident near Edmonds, Washington. It was a personal flight under general aviation rules (Part 91). 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 PARTIAL LOSS OF ENGINE POWER WHEN AN EXHAUST VALVE SEIZED IN THE OPEN POSITION AND THE WATER WHERE THE PILOT WAS FORCED TO LAND, WHICH RESULTED IN AN ACFT NOSE OVER ON TOUCHDOWN.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 26, 1992 · about 3:40 am local time · cases in 1992
- Place
- Edmonds, Washington · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Helio H-391B · all H-391Bs on the register
- Registration
- N4431U · registry record · serial 091
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT INCREASED POWER TO INITIATE A CLIMB AND THE ENGINE PARTIALLY LOST POWER. HE DITCHED THE ACFT IN PUGET SOUND WHEN HE WAS UNABLE TO REACH AN AIRPORT OR THE SHORE FOR AN EMERGENCY LANDING. THE ACFT NOSED OVER ON TOUCHDOWN IN THE WATER. AN EXAM OF THE ENGINE AFTER THE ACCIDENT REVEALED THE NO 4 EXHAUST VALVE WAS SEIZED IN THE OPEN POSITION.
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: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane; rotorcraft: glider
- Flight time: 3,000 hours in all; 190 in this make and model; 30 in the last 90 days; 15 in the last 30 days; 2,500 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,371 hours
- Last inspection: annual inspection, March 26, 1992; 30 hours since
- Maximum gross weight: 3,000 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming GO-435 (piston); 0 hours total
The flight
- Departed from: FRH Friday Harbor WA at 3:15 am
- Destination: BFI Seattle WA
- Flight plan: none
- Runway 0
Weather at the time
- Light: night, dark
- Wind: from 350° at 4 knots
- Visibility: 75 statute miles
- Sky: scat at 25,000 ft
- Temperature: 72°F (22°C), dew point 50°F (10°C)
- Altimeter: 30.00 inHg
- Observation at 3:45 am from PAE, 4 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.
Other NTSB records under N4431U the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N4431U on the register today · the tail number may have moved to another aircraft since
- Helio H-391 16 registered today · the model family and its accident history
- Helio 120 aircraft on the register
- Engine: Lycoming GO-435 33 aircraft carry this series today · as the NTSB recorded it
- French Lick Municipal · departed from
- Boeing Fld/King County International · bound for
- Accidents and incidents in Washington 2,713 since 1982 · 362 in the last ten years
- Washington 10,568 aircraft registered
- Other NTSB records under N4431U 2 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/SEA92LA191.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.