What happened
During the flight phase, the pilot experienced a critical mechanical issue with the number two engine. The oil pressure for this engine dropped to zero, prompting the pilot to feather the propeller to reduce drag and manage the aircraft's performance. Shortly after addressing the engine failure, the number one alternator failed to produce power, leaving the aircraft dependent on its battery system.
As the pilot proceeded with the landing gear extension, the electrical load caused the battery to deplete rapidly. The loss of electrical power resulted in the cockpit instrument lights going out, significantly impairing the pilot's ability to monitor flight instruments during the approach. Despite these challenges, the aircraft was landed; however, it touched down at a speed higher than intended. The aircraft failed to stop within the available runway distance and overran the departure end of the runway. Upon leaving the paved surface, the aircraft collided with an embankment. This impact caused the nose gear to collapse and buckled the nose section of the aircraft.
The investigation
The physical evidence from the accident site indicated a high-speed impact with terrain beyond the runway threshold. The damage pattern was consistent with an overrun event where the aircraft maintained significant forward momentum after leaving the runway surface. The structural damage to the nose gear and fuselage was concentrated at the point of contact with the embankment.
Findings
The sequence of events was driven by a cascading series of system failures. The initial failure of the number two engine oil pressure necessitated feathering, which altered the aircraft's power configuration. The subsequent failure of the number one alternator removed the primary source of electrical generation. The depletion of the battery during the critical phase of landing gear extension led to the loss of cockpit lighting, which likely contributed to the high-speed touchdown and subsequent overrun. The loss of electrical power was a key factor in the inability to maintain proper instrument reference during the final approach.
Safety message
This incident highlights the importance of managing electrical loads during emergency procedures. Pilots should be aware that extending high-draw systems like landing gear during an electrical failure can rapidly deplete battery reserves, potentially leading to a total loss of electrical instruments at critical times. Proper energy management and awareness of system limitations are essential when dealing with multiple simultaneous failures.