What happened
Following a training mission lasting approximately two hours and 40 minutes, the pilot initiated a climb to 9,000 feet AGL to ensure obstacle clearance. During the subsequent descent, the pilot reduced power more aggressively than usual, resulting in a descent rate of approximately 180 KIAS. As the aircraft entered the traffic pattern at an altitude between 800 and 1,000 feet AGL, the pilot attempted to increase power, but both engines suffered a total loss of power.
In response to the dual engine failure, the pilot established an 85 KIAS glide, performed emergency procedures, and retracted the landing gear. The engines failed to restart, and the pilot did not feather the propellers. The landing gear was extended before the aircraft reached the ground. The pilot did not perform a flare during the final approach, leading to a collision with the terrain.
Findings
An investigation into the engine performance noted that soot was present on all spark plugs. While both engines demonstrated normal operation from idle to full acceleration during subsequent examinations, the engine manual warns that extended descents at low power settings should be avoided. Such conditions can lead to excessive engine cooling, which may prevent the engines from accelerating properly when power is reapplied. Additionally, the pilot's descent parameters deviated from the recommended 120 KIAS glide speed suggested in the pilot's operating handbook for dual engine failure scenarios.