Amateur-built Exec 162F accident near Coos Bay, Oregon, March 10, 2005
On March 10, 2005 at about 8:20 pm local time, a amateur-built Exec 162F (helicopter), registered N20539, was destroyed in an accident near Coos Bay, Oregon. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The disintegration, for undetermined reasons, of the upper main drive pulley assembly bearing, while in cruise flight, leading to the decoupling of the main rotor drive assembly from the engine drive assembly. Factors include the absence of any suitable forced landing area, leading to a landing between the gravestones of a cemetery.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 10, 2005 · about 8:20 pm local time
- Place
- Coos Bay, Oregon · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Exec 162F
- Registration
- N20539 · no longer on the register · serial 001
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While in cruise flight, the pilot detected a burning rubber smell and heard "strange loud noises" just as both the engine and rotor rpm began to fluctuate. Soon thereafter, the engine began to lose power, and the pilot elected to make an autorotational landing. He headed for a nearby opening, which turned out to be a cemetery, and as he touched down among the gravestones with zero forward speed, the aircraft rolled over onto its right side. Immediately after it rolled to the side, flames appeared in the cockpit, but the pilot was able to escape out of the left side of the helicopter. A post-accident teardown inspection of the engine and drive assembly revealed that the upper main drive pulley bearing, a double ball bearing assembly, had partially disintegrated, leading to the decoupling of the main rotor shaft drive from the engine output drive shaft. The upper ball bearings were loose in the assembly, and their retaining cage had been destroyed. All of the subject bearings displayed excessive wear, flat spots, and significant thermal damage. Although there was very little grease remaining in the assembly, and the lower drive belt sheave grease passage set screw was found backed half way out, it could not be positively determined whether a lack of lubrication initiated the sequence of events leading to the failure of the bearing assembly, or whether the grease had been consumed by the heat generated by an internal failure resulting from other factors. According to the pilot/builder of the helicopter, he had adhered to the required 25 hour grease service intervals since the aircraft had been built, approximately 115 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: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: helicopter
- Flight time: 20,000 hours in all; 162 in this make and model
- Last flight review: November 1, 2003
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 115 hours
- Last inspection: condition inspection, April 1, 2004; 40 hours since
- Maximum gross weight: 1,500 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway 162F (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: OTH North Bend OR at 9:00 pm
- Destination: Norway OR
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 330° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 0°F (-18°C)
- Altimeter: 30.14 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.
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.