What happened
During cruise flight, the pilot turned off the left half of the split-rocker type master switch. This specific switch controls the alternator, and its deactivation resulted in the battery being drained.
Upon approaching the runway, the crew utilized the emergency method to extend the landing gear. The aircraft touched down on Runway 7 with a wind from 030 degrees at 10 knots. Following touchdown, the aircraft traveled off the right side of the runway and into a ditch. The pilot reported that the brakes were inoperative during the event and noted that the emergency gear extension system was difficult to operate.
The investigation
Maintenance records and inspections revealed that the right main gear tire had developed a flat spot. Subsequent checks of the aircraft systems showed that the brake system, the alternator, and the emergency gear extension system all continued to operate normally without failure or malfunction following the incident.