Sequence of Events
A passenger reported that while the aircraft was approximately 6 miles from the destination airport at 6,000 feet mean sea level (MSL), the pilot initiated a descent. The pilot reduced engine power to idle, placed the propellers to full forward (high RPM), lowered the landing gear, extended the flaps, and slowed the aircraft to 110 knots.
As the airplane descended below the intended approach path on short final approach, the pilot attempted to increase power. However, the right engine did not respond. According to the pilot, the airplane yawed 80 to 90 degrees to the right. Believing a stall was imminent, the pilot reduced power and rolled the wings to level. Subsequently, the aircraft struck trees and the terrain.
Examination Findings
An examination of the aircraft and its systems did not reveal any pre-existing anomalies that could explain the engine's lack of response.
Handbook Guidance
A review of the airplane and engine handbooks revealed cautions against performing rapid descents at idle power settings. The handbooks warned that such descents could lead to low cylinder head temperatures. Additionally, the engine manual noted that long descents at low manifold pressure could excessively cool the engine(s) and result in unsatisfactory acceleration.
Pilot Actions
The pilot did not feather the right engine following the loss of power.