Mcdonnell Douglas 369HS accident near Saipan, In, December 6, 1997
On December 6, 1997 at about 4:49 pm local time, a Mcdonnell Douglas 369HS (helicopter), registered N9068F, was destroyed in an accident near Saipan. It was a flight of an unrecorded kind under general aviation rules (Part 91). 5 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the maintenance facility to comply with the service bulletins, which resulted in the development of a corrosion pit, subsequent leakage and failure of the acceleration bellows of the fuel control.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 6, 1997 · about 4:49 pm local time
- Place
- Saipan, India
- Type
- Accident
- Injuries
- 5 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas 369HS
- Registration
- N9068F · no longer on the register · serial 210293S
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he was making a standard approach to the helicopter pad which was located on a bluff overlooking a golf course. About 100 yards from the pad and 150 feet agl, he noticed a twitch in the nose of the aircraft and heard the rpm decreasing and the engine spooling down. He entered an autorotation and turned the helicopter to the right to avoid upsloping terrain. The aircraft touched down hard and the landing gear collapsed and the tail rotor struck the ground. The pilot stated that after coming to a stop, the engine was still idling so he closed the fuel shutoff valve and throttle and turned off all electrical power. The engine took about 20 to 30 seconds to spool down. The fuel control components were then tested at the Allied Signal Materials Technology Center in South Bend, Indiana, under the auspices of the FAA. Operational bench tests performed on the fuel control and governor indicated that the fuel control would meter minimum fuel flow throughout the various test points and that the acceleration bellows assembly was the probable source for the uncommanded minimum fuel flow condition. A leak was found in the bellows which stemmed from a corrosion pit that penetrated through the outer ply of a convolution tube at the edge of a braze fillet. The pit caused evacuation and malfunction of the bellows. Allied Signal and Allison Engines issued service bulletins on November 18, 1993, regarding the replacement of the fuel control bellows. The Allison Commercial Engine Bulletin CEB-A-282 directed that the beryllium copper bellows be replaced by a stainless steel welded Pc Inconel Bellows the next time the affected fuel control was at a repair/overhaul facility and the bellows area was disassembled for any reason, but in no case later than the next fuel control unit overhaul. The aircraft maintenance records revealed that on April 22, 1997, an overhaul of the fuel control assembly was performed. On a form indicating compliance with applicable service bulletins and directives, 'NA' was written by the maintenance facility in the space next to the listing for the Allison CEB-282. The records revealed that the fuel control with the beryllium copper Pc bellows was reinstalled in the helicopter on October 1, 1997, at engine time 2,247.1 hours, 39 hours prior to the accident.
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; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 13,500 hours in all; 3,005 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 1,806 hours
- Last inspection: annual inspection, August 27, 1997; 41 hours since
- Maximum gross weight: 2,550 lb
- Seats: 5
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Micronesian Aviation CORP
The flight
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 070° at 13 knots
- Visibility: 7 statute miles
- Sky: scat at 1,500 ft
- Temperature: 82°F (28°C), dew point 73°F (23°C)
- Altimeter: 29.00 inHg
- Observation at 5:00 pm from PGS
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.
Other NTSB records under N9068F 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.