Incident Description
A student pilot, who was already rated, was on his first instructional flight in the aircraft. During the session, a practice aborted takeoff was performed. Subsequently, the student applied power to initiate another takeoff. At that moment, the aircraft began to veer to the right. The instructor applied left rudder and instructed the student to reduce power. Despite these actions, the aircraft continued its rightward movement and eventually struck a snowbank.
Investigation Findings
After the incident, investigators conducted operational checks on the engines. The right engine, when tested with the fuel boost pumps turned off, functioned normally. However, when the boost pump switch was placed in the high position, the engine exhibited abnormal behavior. Specifically, when the throttle was retarded from a high power setting and then readvanced, the engine did not respond properly. Fuel flow remained high, and black emissions were observed from the exhaust system. Additionally, when the throttle was retarded, the engine would stop running altogether. In contrast, the left engine operated normally under the same test conditions.
During the investigation, the instructor suspected a malfunction of the fuel pump pressure switch as a possible cause of the right engine's erratic performance.