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).
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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 October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 26, 1992 · about 3:40 am local time
- 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 |
Other NTSB records under N4431U the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number SEA92LA191.