Amateur-built LANCAIR IV P incident near Fulton, New York, June 1, 2017
On June 1, 2017 at about 10:30 pm local time, a 2000 amateur-built LANCAIR IV P, registered N366TF, was involved in an incident during maneuvering near Fulton, New York (Oswego County airport). It was a personal 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 oil pressure and subsequent engine overspeed/surge during a zero g-force maneuver, which resulted in the separation of a crankshaft counterweight and loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 1, 2017 · about 10:30 pm local time
- Place
- Fulton, New York · Oswego County · map
- Type
- Incident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built LANCAIR IV P NO SERIES, built 2000
- Registration
- N366TF · registry record · serial LIV-388
- Damage
- Not recorded
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot and a flight instructor planned to conduct an inflight calibration of an angle of attack indicator. Following a zero g-force maneuver, engine oil pressure decreased to 3 psi and engine speed increased to 3,140 rpm. Immediately after the engine overspeed, a total loss of power occurred. The pilot performed a forced landing to the departure airport without further incident. Examination of the engine revealed one of the two rear crankshaft counterweights (6th order) separated from the crankshaft, with a 6th order counterweight connecting pin lodged in the crankcase between cylinder Nos. 4 and 6. An impression in the No. 1 connecting rod matched the shape of a 6th order counterweight connecting pin. The oil sump contained significant debris, including four counterweight pin retaining snap rings, four counterweight pin retainer plates, and two 6th order counterweight connecting pins. Based on the examination, the lack of oil pressure and subsequent engine rpm overspeed/surge likely caused the separation of the crankshaft counterweight and engine failure.
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
What happened, in order
- Loss of engine power (total) during maneuvering defining event
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Failure
- cause Aircraft › Fluids/misc hardware › Fluids › Oil › Related operating info
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 1,204 hours in all; 1 in this make and model; 12 in the last 90 days; 5 in the last 30 days; 1,140 as pilot in command; 137 on instruments
- Last flight review: May 10, 1997
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 1,146.6 hours
- Last inspection: condition inspection, November 16, 2016
- Seats: 4
- Landing gear: retractable
- Engine: Cont Motor TSIO-550 SER (piston); 1,105 hours total
The flight
- Departed from: FZY Fulton NY at 10:15 pm
- Destination: FZY Fulton NY
- Flight plan: none
- Runway 33, 5,196 ft by 100 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 300° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 39°F (4°C)
- Altimeter: 29.96 inHg
- Observation at 10:54 pm from KFZY
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on June 14, 2018. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Engine Maintenance Records | PDF, 35 pages | View Download |
| 3 | Service Bulletin - SB00-3A | PDF, 35 pages | View Download |
| 4 | Photos | PDF, 5 pages | View Download |
| 5 | Flight Data Download | data file | Download |
| 6 | Alert from Lancair Owners and Builders Organization | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N366TF 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.