Mcdonnell Douglas 369E accident near Hilo, Hawaii, February 8, 2008
On February 8, 2008, a Mcdonnell Douglas 369E (helicopter), registered N698DM, was substantially damaged in an accident during enroute (cruise) near Hilo, Hawaii (Hilo airport). It was flown under charter and air-taxi rules (Part 135). 5 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A leak in the fuel filter pressure differential switch that resulted in a loss of engine power. Contributing to the accident was uneven terrain that hindered a successful emergency landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 8, 2008
- Place
- Hilo, Hawaii · Hilo · map
- Type
- Accident
- Injuries
- 5 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas 369E
- Registration
- N698DM · registry record · serial 348E
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The flight was approximately five miles from the departure airport when the pilot turned back due to a fuel bypass caution light. The pilot heard 2-3 abnormal engine sounds, with simultaneous yawing, during the turn and entered an autorotation. During the final stages of the autorotation, the engine flamed out. The helicopter touched down on uneven terrain and rolled over resulting in substantial damage. Post accident examination of the engine assembly revealed a fuel leak from the fuel filter pressure differential switch. The differential switch was in place and the associated fuel lines, bushing and adapter fitting were not damaged. Examination of the system revealed that one of the three fuel filter pressure differential switch set screws, and associated safety wire segment, was missing. The two remaining screws were in place. One of the screws was fixed, the other finger tight. The corresponding safety wire was attached to the remaining set screws. The distal end of the safety wire leading to the missing set screw was severed. A post accident evaluation of the engine in a production test cell revealed a fuel leak at the pressure differential switch when the engine was motored to 16 percent N1 (compressor speed). The original fuel filter pressure differential switch was removed and replaced with an exemplar differential switch. A second engine start was successful and the engine ran, without leaks, and attained normal operating parameters. Maintenance records indicated that the helicopter's fuel system components were inspected during the 100-hour inspection completed 66 flight hours before the accident. The maintenance "check sheet" indicated that the engine's fuel system components, to include fuel lines and connections, were inspected for leaks or damage, and no anomalies were noted. No record was found in the maintenance records of any work done to the fuel filter pressure differential switch subsequent to the 100-hour inspection. It could not be determined when, or how, the fuel filter pressure differential switch set screws, and associated safety wire came loose. The approved maintenance manual for the helicopter contains multiple warnings indicating that air in the closed fuel system will cause a power reduction or flame out.
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 (total) during enroute (cruise) defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- cause Aircraft › Aircraft systems › Fuel system › (general) › Malfunction
- factor Environmental issues › Physical environment › Terrain › Sloped/uneven › Contributed to outcome
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; rotorcraft: helicopter
- Flight time: 19,800 hours in all; 850 in this make and model; 65 in the last 90 days; 38 in the last 30 days; 19,500 as pilot in command
- Last flight review: December 12, 2007
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 9,118 hours
- Last inspection: 100-hour inspection, January 18, 2008; 66 hours since
- Maximum gross weight: 3,000 lb
- Seats: 5
- Landing gear: fixed
- Engine: Rolls-Royce Allison 250-C20B (turboshaft); 0 hours total
The flight
- Departed from: PHTO Hilo HI
- Destination: PHTO Hilo HI
Weather at the time
- Light: daylight
- Wind: from 140° at 12 knots
- Visibility: 6 statute miles
- Sky: broken clouds at 2,000 ft; scat at 1,500 ft
- Temperature: 68°F (20°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 4 |
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.