Amateur-built Rotorway INTL 162F accident near Argyle, New York, May 21, 2007
On May 21, 2007 at about 10:00 pm local time, a amateur-built Rotorway INTL 162F (helicopter), registered N636PB, was substantially damaged in an accident near Argyle, New York (Argyle airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of engine power due to the sticking of the exhaust valves that resulted from carbon buildup.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 21, 2007 · about 10:00 pm local time
- Place
- Argyle, New York · Argyle · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Rotorway INTL 162F
- Registration
- N636PB · no longer on the register · serial 6636
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The certified flight instructor (CFI) stated that the purpose of the flight was instruction. He conducted a preflight of the helicopter and did not note any problems with the helicopter. Start up and run up was completed by the checklist with no problems. They lifted off, hovered for a few minutes and landed again. Shortly thereafter they departed an airport for training. The takeoff and climb were normal, and they leveled off at 1,500 feet. Approximately 3 miles from the airport, the engine began to run rough and there was a drop in power. The dual student transferred the flight controls to the CFI. The CFI decided not to continue the flight to the airport, and initiated an approach to a field behind a house. On approach the engine stopped, and an autorotation was initiated to the field. The touchdown was "smooth" and level, with a slow forward speed. The helicopter slid approximately 10 feet and rolled over onto the left side. Examination of the helicopter by an FAA inspector revealed no flight control anomalies. The pilot reported that the helicopter was fine until the engine power began decrease. The examination of the engine revealed that the number 4 rocker arm was unsecured and the spring retainer was damaged. Further examination revealed that the number 4 exhaust valve had stuck in the open position. In a review of the logbook it was discovered that the mechanic had made valve lash adjustments to all the cylinders on September 16, 2006, at an engine tachometer time of 17.4 hours. The engine tachometer time at the accident site was 18.1 hours. The engine had .7 hours before the exhaust valve failed. The cylinder heads were sent to Rotorway International for examination of the exhaust and intake valves. According to Rotorway, examination of the heads revealed that the exhaust valves were found to be "sticky in their guides". The guide size measured at the low side of the tolerance before cleaning. After cleaning with a wire brush, the fit of the valves in the cylinder heads and the tolerance of sizes were acceptable.
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
Flight instructor
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: helicopter; instructor: instrument airplane; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 18,000 hours in all; 17 in this make and model
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 17 hours
- Last inspection: condition inspection, May 1, 2007; 0.6 hours since
- Maximum gross weight: 2,400 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway 150W (piston); 0 hours total
The flight
- Departed from: Private Strip NY at 9:45 pm
- Destination: NY02 Argyle NY
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 330° at 7 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,100 ft; ovct at 4,100 ft
- Temperature: 46°F (8°C), dew point 39°F (4°C)
- Observation at 9:15 pm from KGFL, 8 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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.