Enstrom F-28F accident near Skwentna, Alaska, July 25, 1998
On July 25, 1998 at about 10:00 pm local time, a Enstrom F-28F (helicopter), registered N8622U, was substantially damaged in an accident near Skwentna, Alaska. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to a fractured number three cylinder intake manifold flange, and the pilot's inability to maintain the proper rate of descent during the autorotation flare. A contributing factor associated with the accident was the downwind (tailwind) landing condition.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 25, 1998 · about 10:00 pm local time
- Place
- Skwentna, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom F-28F · all F-28Fs on the register
- Registration
- N8622U · registry record · serial 721
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The certificated commercial helicopter pilot was conducting a salmon survey for the State of Alaska, Department of Fish & Game. This operation required him to hover the helicopter over the stream while the passenger, a wildlife biologist employed by the State of Alaska, noted the number of fish. The pilot stated that while in a hover above the stream, he felt a slight vibration followed by a partial loss of engine power. He said that while hover taxiing the helicopter to a suitable landing area, the engine continued to lose power, and he was forced to make a downwind autorotation. He said that as the helicopter touched down, the main rotor blades flexed downward, and struck the tail boom. The helicopter's tail boom, and tail rotor gearbox sustained substantial damage. The operator reported that during a postaccident inspection of the engine, a fractured intake manifold flange was discovered on the number three cylinder assembly.
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: commercial pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane; rotorcraft: helicopter
- Flight time: 11,000 hours in all; 1,200 in this make and model; 200 in the last 90 days; 80 in the last 30 days; 11,000 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 1,280 hours
- Last inspection: annual inspection, February 28, 1998; 74 hours since
- Maximum gross weight: 2,600 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO 360 (piston); 0 hours total
The flight
- Departed from: SKW AK at 3:45 pm
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 120° at 10 knots, gusting 15
- Visibility: 7 statute miles
- Sky: overcast at 1,500 ft; not recorded
- Temperature: 55°F (13°C), dew point 0°F (-18°C)
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.
Other NTSB records under N8622U the same tail number, which may have belonged to a different aircraft at the time
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.