Accident Overview
The airplane overran the departure end of the runway during an aborted landing attempt and collided with a ditch. The pilot reported that the winds were variable at about 3 knots and had set up for landing on runway 24, which the airport had identified as the preferred calm wind runway. According to the airport, runway 24 is a downhill runway with about a 1.9 percent slope.
Pilot Actions
After a normal touchdown, the pilot applied the brakes, which felt mushy. He decided to go around. After adding power, the left engine went into an over-boost condition, so he reduced the power, kept the airplane on the ground, and applied brakes. The pilot was unable to stop the airplane, and it ran off the end of the runway and collided with a ditch.
Post-Accident Examination
Airframe and engine examinations were conducted following recovery of the airplane from the accident site. There were no mechanical discrepancies noted with the airframe. The aircraft brake system was inspected. The left main gear was folded into the wheel well and could not be visually examined. Pressure was applied to the left rudder/brake pedal, and normal resistance was felt. The hydraulic brake line was loosened at the left wing root connection, and fluid was observed coming out of the line with pedal application.
The right hydraulic line was disconnected at the wing root during recovery operations. Pressure was applied to the brake pedal, and a "gurgling" sound was detected at the line opening, and fluid was observed coming out of the line. The right side brakes were then disassembled. No deep grooving was observed on the disc, which had a measured thickness of 0.687 inches. The three brake back plates had thicknesses of approximately 0.125, 0.156, and 0.125 inches, respectively.
The spark plugs from both engines exhibited coloration consistent with operation in the normal range. The electrodes were normal to slightly worn in appearance. Normal range compression was developed in each engine's cylinders with manual rotation of the crankshafts. A visual borescope inspection of the cylinders on the left engine revealed no evidence of detonation. The turbocharger system was removed and functionally checked.