Amateur-built GT-500 accident near Willows, California, November 25, 2017
On November 25, 2017 at about 11:15 pm local time, a 2009 amateur-built GT-500, registered N599RA, was substantially damaged in an accident during takeoff near Willows, California (Willows-Glenn County airport). It was an instructional flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power during takeoff due a coolant leak and the subsequent overheating of the engine, and the student pilot's failure to maintain airspeed and his exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall and collision with terrain. Contributing to the accident was inadequate maintenance inspection and the flight instructors delayed remedial action.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 25, 2017 · about 11:15 pm local time
- Place
- Willows, California · Willows-Glenn County · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built GT-500 NO SERIES, built 2009
- Registration
- N599RA · registry record · serial 0151
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor and the student pilot, who was the pilot flying, departed for the third leg of the cross-country flight. The student pilot indicated that shortly after takeoff, when the airplane was about 70 ft above the runway, the engine sputtered and then lost power. He stated that he attempted to land straight ahead but did not maintain proper airspeed. The video from an onboard camera showed that after the engine lost power, the student pilot pulled back on the yoke, and the airplane rapidly descended toward the runway and impacted the ground likely following an aerodynamic stall. Postaccident examination of the engine revealed that the radiator coolant level was low enough that the fluid was not visible through the radiator cap. The examination revealed a coolant leak around the water pump housing nipple due to an improper seal of the hose to the nipple attachment. In addition, the radiator recovery and overflow bottle were improperly installed, which prevented the system from refilling coolant into the radiator during the engine cooling period in between flights. The intake port sides of the cylinders had antifreeze particles embedded into their surfaces consistent with overheating. The top portion of the No. 1 piston exhibited melted metal deposits from spark plug electrodes consistent with preignition and detonation, and the No. 2 piston exhibited discoloration and burnt-on carbon deposits consistent with the piston overheating for a period of time. It is likely that the airplane had lost a significant amount of coolant during the previous legs of the cross-country flight, which led to an overheated cylinder and subsequent engine failure. In addition, the student pilot failed to maintain airspeed after the partial loss of engine power. The airplane exceeded its critical angle of attack, which resulted in an aerodynamic stall at an altitude too low to recover.
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 takeoff defining event
- Collision with terrain or object (not controlled flight into terrain) during landing
- Aerodynamic stall/spin during emergency descent
The NTSB's findings
- factor Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng liquid cooling › Damaged/degraded
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Angle of attack › Capability exceeded
- Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Other
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Student/instructed pilot
- Personnel issues › Psychological › Attention/monitoring › Monitoring other person › Instructor/check pilot
Dual student
- Certificate: student
- Flight time: 200 hours in all; 145 in this make and model
- Last flight review: November 18, 2017
- Medical certificate: None
- Seat: frt
- Injury: minor injuries
Flight instructor
- Certificate: flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 2,835 hours in all; 4 in this make and model
- Last flight review: June 7, 2017
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: rear
- Injury: minor injuries
The aircraft
- Airframe total time: 1,451.3 hours
- Last inspection: annual inspection, December 9, 2016
- Maximum gross weight: 1,000 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 582UL-99 (piston); 0 hours total
The flight
- Departed from: WLW Willows CA at 11:15 pm
- Destination: 0O4 Corning CA
- Flight plan: none
- Runway 16, 4,125 ft by 100 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 150° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 66°F (19°C), dew point 55°F (13°C)
- Altimeter: 29.98 inHg
- Observation at 10:53 pm from KOVE, 28 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on December 31, 2020. 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, 10 pages | View Download |
| 2 | Record of Conversation | PDF, 1 page | View Download |
| 3 | Engine Exam | PDF, 21 pages | View Download |
| 4 | Photo of the Wreckage | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.