Mcdonnell Douglas 369D accident near Hana, Hawaii, November 13, 1996
On November 13, 1996, a Mcdonnell Douglas 369D (helicopter), registered N8625F, was substantially damaged in an accident near Hana, Hawaii. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
subsequent failure of the spur adapter gearshaft (SAG), after 'retaining ring to compressor impeller machining' occurred and allowed the SAG to shift aft. The mechanism which induced the ring to impeller machining was not determined. Mountainous terrain in the emergency landing area was a related factor.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 13, 1996
- Place
- Hana, Hawaii · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas 369D
- Registration
- N8625F · no longer on the register · serial 470111D
- 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
During flight, the pilot heard a loud noise from the engine compartment, accompanied by the engine out light & horn. He entered an autorotation, & the helicopter rolled over during touchdown on mountainous terrain. Disassembly of the engine revealed the forward splines of the Spur Adapter Gearshaft (SAG), which connected the compressor & turbine module shafts, had fractured, & the compressor module was disconnected from the turbine section. The SAG retaining ring was found to have machined into the compressor impeller, which allowed the SAG to shift aft. Aft movement of the SAG then resulted in heavy wear on the splines of both the Compressor Adapter Coupling (CAC) & the SAG, which resulted in a fatigue failure of the SAG splines. The CAC & impeller were of an old configuration. Allison Commercial Engine Bulletin 1325 recommended replacement of the old CAG, SAG, impellers, & retaining rings with models of a newer design to 'improve spline wear characteristics.' Allison engineers opined that the typical retaining ring to impeller machining was due to the same retaining ring being returned to the engine during overhaul, though evidence of this was not apparent in the engine examination.
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; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 5,350 hours in all; 3,700 in this make and model; 260 in the last 90 days; 70 in the last 30 days; 5,200 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 17,998 hours
- Last inspection: 100-hour inspection, October 12, 1996; 79 hours since
- Maximum gross weight: 3,000 lb
- Seats: 5
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Alika Aviation
The flight
- Departed from: OGG Kahului HI
- Runway 0
Weather at the time
- Light: daylight
- Wind: at 5 knots
- Visibility: 20 statute miles
- Sky: overcast at 3,000 ft; not recorded
- Temperature: 68°F (20°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.