Doshier Wilbert A GT-500 N599RA

Summary

On 25 November 2017 at about 23:15 local time, a Doshier Wilbert A GT-500 registered N599RA was involved in an accident near Willows, California, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

25 November 2017 at 23:15

Classification

Accident

Location

Willows, California, United States

Nearest airport

Willows-Glenn County (WLW)

Coordinates

39.5158, -122.2172

Aircraft

Doshier Wilbert A GT-500

Registration

N599RA

Category

Airplane

Year built

2009

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Willows → Corning

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR18LA036

2 people had minor injuries.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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. 

Quoted verbatim from the NTSB record.