Event Description
While en route in instrument meteorological conditions (IMC), the pilot of a twin-engine, piston-powered airplane declared an emergency after a loss of power to the right engine. The pilot secured the failed engine and received vectors from air traffic control for an instrument approach procedure to the nearest airport, which was completed successfully. The pilot reported flying the approach and landing with the wing flaps retracted. He visually acquired the runway about 500 ft above ground level. The airplane touched down on the first third of the runway at a speed of 120 knots. Recognizing that he could not stop on the 3,500-ft runway, the pilot committed to landing rather than risk a single-engine go-around in IMC. After touchdown, the airplane continued beyond the departure end of the runway, impacted a berm, collapsed the landing gear, and sustained substantial damage.
Engine Examination
Examination of the right engine revealed catastrophic damage consistent with detonation and subsequent oil starvation. Damage to the No. 5 cylinder was consistent with overpressurization of the crankcase, which likely expelled the crankshaft nose seal and the oil supply. Detonation of the cylinder(s) can create excessive crankcase pressures capable of displacing the crankshaft nose seal. The seal displacement likely caused rapid oil loss and subsequent oil starvation. The fractured connecting rod and high-temperature signatures were consistent with oil starvation. No source or anomaly that would result in engine detonation was identified.
Pilot's Actions and Published Guidance
According to the Pilot’s Operating Handbook (POH) for the accident airplane, during a single-engine inoperative approach the pilot should maintain an airspeed of 116 KIAS or above until landing is assured. Once landing is assured, the pilot should extend the landing gear and flaps, slowly retard power on the operative engine, and land normally. The airplane’s best single-engine rate of climb speed (blue line) was 106 KIAS, and its minimum controllable airspeed with one engine inoperative (Vmca) was 76 KIAS. The maximum speed for full flap extension (40°) was 132 KIAS. The POH also stated that a single-engine go-around should be avoided if at all possible. The pilot’s decision to commit to the landing was reasonable given the circumstances and POH guidance; however, it is likely that the decision to land without flaps and the excessive airspeed at touchdown resulted in the runway overrun.