What happened
On 30 November 2000, a KIS TR4 aircraft, registration ZU-BKK, was conducting its fourth test flight following construction. The flight was being operated privately, with the pilot accompanied by the aircraft's owner/builder. While orbiting above Grand Central aerodrome (FAGC), the aircraft's engine experienced a sudden failure.
During the flight, approximately 20 minutes after departure, a laptop computer connected to the engine management system displayed a cam sensor failure message. Because the engine is powered by a Subaru automotive engine, the management system is programmed to automatically terminate engine operation if it detects mechanical issues that might cause internal damage. Following the initial failure, the owner successfully reset the computer and restarted the engine, but the system triggered a second automatic shutdown shortly thereafter.
In the ensuing attempt to land on runway 35, the pilot miscalculated the aircraft's high rate of descent. Consequently, the aircraft struck a steep grass embankment before reaching the runway threshold.
The investigation
The investigation focused on the interaction between the engine's electronic monitoring system and the engine's operation. Investigators examined the engine management computer and its connection to various sensors, specifically the sensor responsible for monitoring cam position relative to the engine. It was established that the engine management system functioned as designed by cutting ignition to prevent potential mechanical damage following the detection of a sensor error.
Findings
- The engine management computer automatically shut off the engine after detecting a failure in the cam sensor.
- The pilot misjudged the aircraft's high sink rate during the approach to runway 35.
- The aircraft impacted a grass embankment short of the runway threshold.