Amateur-built DHC-4A accident near Sparrevohn, Alaska, January 30, 1997
On January 30, 1997 at about 3:10 am local time, a amateur-built DHC-4A, registered N702SC, was destroyed in an accident near Sparrevohn, Alaska (Sparrevohn Lrrs airport). It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
loss of the right engine propeller control oil, which led to an overspeed of the right engine and propeller, and necessitated a shut-down of the right engine; and failure of the pilot to maintain adequate altitude/distance from terrain during visual approach for a precautionary landing at an alternate airport. Factors relating to the accident were: fluctuation of the left engine power, premature lowering of the airplane flaps, and an encounter with adverse weather conditions (including high winds, severe turbulence, and white-out conditions) during the approach.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 30, 1997 · about 3:10 am local time
- Place
- Sparrevohn, Alaska · Sparrevohn Lrrs · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built DHC-4A
- Registration
- N702SC · registry record · serial 126
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The CFR Part 135 cargo flight (flt) departed at night on an IFR flt with a load of mining equipment. Route of flt was over remote/mountainous terrain. About 2 hrs after takeoff, while cruising at 12,000' msl, the right engine (#2 eng) & propeller began to overspeed. The captain (capt) feathered the #2 eng & declared an emergency. He began to divert to an alternate destination, about 120 miles away in an area of lower terrain, but the aircraft (acft) would not maintain altitude (single eng service ceiling, as loaded, was about 8,700'). The capt increased power to the #1 eng, but it began to produce banging & coughing noises. The capt elected to perform an emergency landing at a nearby, remote, military airfield (A/F). The A/F was located in mountainous terrain & had a one-way, daylight only approach. The capt lowered the gear & flaps, & began a visual approach while attempting to keep the runway end identifier lights (REIL) in view. The acft encountered severe turbulence, & the capt applied full throttle to the #1 eng in an attempt to climb. The REIL disappeared from view, & the acft collided with snow covered terrain about 2 miles west of the A/F. Ground personnel at the A/F reported high winds & blowing snow with limited visibility. Postcrash exam of the #2 eng revealed a loss of the propeller control system hydraulic oil. Flt at 12,000' was conducted without crew oxygen. The crew had exceeded their maximum allowable duty day without adequate crew rest.
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: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 4,987 hours in all; 220 in this make and model; 120 in the last 90 days; 41 in the last 30 days; 4,912 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 13,923 hours
- Last inspection: approved inspection programme, December 30, 1996; 12 hours since
- Maximum gross weight: 28,500 lb
- Seats: 3
- Landing gear: retractable
- Engine: P&W R-2000 (piston); 0 hours total
- Operator: South Central Air
The flight
- Departed from: KSM St Marys AK at 1:05 am
- Destination: ENA Kenai AK
- Flight plan: IFR
- Runway 34, 4,100 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: night, dark
- Wind: from 170° at 6 knots
- Visibility: 10 statute miles
- Sky: overcast at 6,000 ft; scat at 4,800 ft
- Temperature: 28°F (-2°C), dew point 21°F (-6°C)
- Altimeter: 28.00 inHg
- Observation at 3:15 am from SVW, 2 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 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.