Mcdonnell Douglas 369D accident near Volcano, Hawaii, June 15, 2003
On June 15, 2003 at about 7:35 pm local time, a Mcdonnell Douglas 369D (helicopter), registered N4493M, was destroyed in an accident near Volcano, Hawaii. It was flown under charter and air-taxi rules (Part 135). 4 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
a loss of engine power due to the fatigue fracture and separation of the compressor coupling adapter. The fatigue fracture was initiated by fretting on the pilot diameter due to both the inadequate design of the coupling and the coaxial misalignment of the spur adapter gear, compressor-coupling adapter, and compressor impeller during recent engine maintenance where the gearbox was removed and replaced. A factor in the accident was the unsuitable nature of the terrain to make an emergency landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 15, 2003 · about 7:35 pm local time
- Place
- Volcano, Hawaii · map
- Type
- Accident
- Injuries
- 4 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas 369D
- Registration
- N4493M · no longer on the register · serial 570137D
- Damage
- Destroyed
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The helicopter crashed onto a rugged hardened lava flow following a loss of engine power during cruise. The pilots of other helicopters heard the pilot make a mayday call with the clear "engine out" audio warning in the background. A post crash fire consumed the majority of the wreckage. An airframe examination revealed no evidence of a preimpact malfunction in what remained of the airframe. An engine inspection and a metallurgical examination revealed that the compressor-coupling adapter, a Parts Manufacturer Approval (PMA) part made by a company other than Rolls-Royce, had failed above the shear point due to fatigue cracking initiated by fretting on the pilot diameter, which had disconnected the compressor from the turbine section. The metallurgist noted that the damage was consistent with the rotation of the aft piece of the fractured compressor-coupling adapter within the stub shaft after it had separated. Fretting damage to the impeller corresponded to the fretting damage on the compressor-coupling adapter, and indicated relative movement between the parts. Rolls-Royce had records of 12 other compressor-coupling adapters that had fractured and failed, with all instances of the failure/fracture occurring in this specific new coupling design, which was significantly different than the previous design. The nature of the fretting and fractures indicated that the newly designed couplings have a small amount of longitudinal movement that is occurring between the outer diameter of the compressor-coupling adapter and the inner diameter of the impeller, which was not a factor in the previous design. If the spur adapter gear, compressor-coupling adapter, and compressor impeller (all coaxial spline joints) were in alignment, there would be no significant longitudinal movement of the pilot diameter. However, any axial misalignment of these components during engine buildup, for example, could induce a misalignment that would result in relative motion between the components with each engine rotation. The misalignment would also induce bending stresses into the compressor-coupling adapter in addition to torsion stresses that could result in fatigue. The combination of fretting damage and cyclic bending stresses are most likely the main factor in the failures of these couplings. One month prior to the accident, company maintenance personnel had changed out the engine gearbox due to finding a loose stud on the gearbox to turbine section mounting. Changing the gearbox would involve disturbing the coaxial spline joints between the spur adapter gear, compressor-coupling adapter, and compressor impeller.
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: rotorcraft: helicopter
- Flight time: 3,300 hours in all; 2,800 in this make and model; 30 in the last 30 days
- Last flight review: April 1, 2003
- Medical certificate: Class 2
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 7,859.3 hours
- Last inspection: continuous airworthiness programme, June 1, 2003; 7,836.1 hours since
- Maximum gross weight: 3,000 lb
- Seats: 5
- Landing gear: fixed
- Engine: Rolls-Royce 250 C20B (turboshaft); 0 hours total
- Fire on the ground
The flight
- Departed from: ITO Hilo HI at 7:15 pm
- Destination: ITO
Weather at the time
- Light: daylight
- Wind: from 020° at 8 knots
- Visibility: 10 statute miles
- Sky: scat at 8,500 ft
- Temperature: 81°F (27°C), dew point 68°F (20°C)
- Altimeter: 30.05 inHg
- Observation at 7:53 pm from ITO, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 3 |
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 N4493M 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.