What happened
On April 1, 2017, a pilot was conducting a navigation flight as part of a training program for junior flight crew near the EPCD airfield. Approximately 100 minutes into the flight, the pilot noticed that the alternator switch was in the off position. Upon switching the alternator on, the charging indicator moved to its maximum rightward position. After attempting to restart the alternator several times without success, the pilot decided to terminate the mission and return to the departure airfield.
The investigation
The investigation established that the pilot had failed to engage the alternator switch during the initial engine start sequence. When the switch was finally activated 100 minutes into the flight, the charging indicator's position at the maximum rightward limit was actually a correct indication of the battery being discharged. The investigation found that the pilot misidentified this reading as a sign of alternator failure or excessive charging current, which led to the repeated, unsuccessful attempts to restart the component.
Findings
- The primary cause of the incident was the incomplete execution of the engine start procedure by the pilot.
- This procedural error led to a secondary misinterpretation of the cockpit instrumentation.
- The pilot's limited experience contributed to the incorrect assessment of the electrical system status during the flight.