What happened
On May 18, 2015, during an engine test prior to flight, the pilot of a Schweizer 300C helicopter experienced difficulty starting the engine. During the testing process, a drop in RPM of 250 rpm was observed on one of the magnetos, which was accompanied by irregular engine operation. The operator reported that the issue was addressed by adjusting the ignition timing advance, though initial reports suggested high-voltage leads might have been responsible.
Several days after this initial event, the same aircraft was involved in a second incident. During this flight, the pilot was forced to perform a precautionary landing following a loss of engine power. The investigation established that this second occurrence was caused by a technical failure within the ignition system.
The investigation
The PKBWL examined the sequence of events involving the two separate engine-related incidents. The investigation focused on the technical failures occurring during the engine tests and the subsequent flight. The inquiry confirmed that the second incident was directly linked to the degraded condition of the ignition system.