What happened
During a positioning flight, a twin-engine medical transport airplane experienced a loss of power in one engine. The aircraft was initially at 2,600 feet and descending shallowly approximately 8 miles northwest of the airport when the pilot contacted the tower to request landing. Roughly three and a half minutes later, the pilot reported an engine failure while performing a right-hand turn.
Radar tracking showed the aircraft at 1,200 feet MSL, two miles southwest of the airport, continuing in a descent and a right turn. The aircraft's altitude fluctuelated between 400 and 600 feet as the track shifted to a 100-degree magnetic heading, placing the plane on a left base for the runway. A third right-hand turn occurred at 500 feet. The pilot's final communication confirmed one engine was not producing power. Six seconds later, radar lost the aircraft at 200 feet near the wreckage site. Ground speed calculations indicated a steady deceleration from 134 knots to 76 knots just before the impact with terrain.
Findings
An analysis of air traffic control audio revealed a significant power imbalance, with one engine at 2,630 rpm and the other at 1,320 rpm. Propeller damage indicated the right engine was producing much higher power than the left, and neither propeller had been feathered. While an engine teardown showed no mechanical malfunctions, the aircraft was in a high-drag configuration with the landing gear down and flaps fully deployed at the time of impact.
Calculations determined that level flight was impossible in this configuration with one engine inoperative. Once the airspeed dropped below the minimum controllable airspeed (VMC), the aircraft became susceptible to stalling and rolling toward the dead engine. Although the pilot was trained for single-engine landings, the operator's training did not specifically practice flight at VMC with one engine inoperative. Furthermore, while the operator's manual emphasized reducing drag during engine failures, it lacked specific procedures to achieve this, and the ground syllabus did not adequately cover engine-out performance in various configurations. The existing emergency checklists provided instructions to feather the propeller and retract gear/flaps to maintain performance, but these were not implemented.