Dehavilland BEAVER DHC 2 accident near Thorne Bay, Alaska, July 24, 2013
On July 24, 2013 at about 7:40 pm local time, a Dehavilland BEAVER DHC 2, registered N4787C, was substantially damaged in an accident during enroute (cruise) near Thorne Bay, Alaska. It was flown under charter and air-taxi rules (Part 135). 3 people were seriously injured; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the No. 1 linkrod bushing or the bottom portion of the linkrod, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 24, 2013 · about 7:40 pm local time
- Place
- Thorne Bay, Alaska · map
- Type
- Accident
- Injuries
- 3 people were seriously injured; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Dehavilland BEAVER DHC 2 · all BEAVER DHC 2s on the register
- Registration
- N4787C · registry record · serial 1330
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, while the float-equipped airplane was in cruise flight about 1,200 ft above ground level, the engine made a loud noise and lost partial power, so he maneuvered the airplane to land on a nearby lake. During the approach, the engine lost total power, and the airplane descended into an area of trees before reaching the lake, which resulted in substantial damage to the wings, fuselage, and empennage. The operator reported that the engine had been overhauled (zero-timed) 31 hours before the accident. A postaccident engine examination revealed metal fragments and heavy gouging damage to the rotating components within the crankcase. The bottom portion (crankshaft end) of the No. 1 linkrod and its respective bushing were missing from the No. 1 linkpin; the oil sump contained metal debris consistent with heavily damaged remnants of these (and other) components. The No. 2 cylinder barrel and linkrod and the No. 3 linkrod showed deformation to the left (in the direction of engine rotation). Based on the damage observed in the engine, it is likely that the event that initiated the engine failure involved either the the No. 1 linkrod bushing or the bottom portion of the No. 1 linkrod; however, the extensive damage to these components precluded determination of the failure mode.
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
What happened, in order
- Loss of engine power (partial) during enroute (cruise) defining event
- Loss of engine power (total) during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › (general) › Failure
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; multi-engine sea; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 19,500 hours in all; 600 in this make and model; 189 in the last 90 days; 117 in the last 30 days; 19,400 as pilot in command
- Last flight review: May 31, 2013
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
Passenger
- Seat: ctr
- Injury: no injuries
Passenger
- Seat: ctr
- Injury: serious injuries
Passenger
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 33,326 hours
- Last inspection: approved inspection programme, July 10, 2013
- Maximum gross weight: 5,110 lb
- Seats: 9
- Landing gear: fixed
- Engine: Pratt & Whitney R-985AN-14B (piston); 6,061 hours total
- Operator: Promech Air LLC
The flight
- Departed from: 5KE Ketchikan AK
- Destination: Shipley Bay AK
Weather at the time
- Light: daylight
- Wind: from 120° at 5 knots
- Visibility: 10 statute miles
- Sky: overcast at 2,500 ft
- Temperature: 61°F (16°C), dew point 55°F (13°C)
- Altimeter: 30.09 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 | 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 N4787C 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.