What happened
While approximately five miles from its destination, the aircraft was cleared by air traffic control to descend from a cruise altitude of 5,000 feet to prepare for a visual approach. During the descent, as the first officer decreased engine power, both engines ceased operation. The captain attempted to initiate an engine restart, but the efforts were unsuccessful. After taking control of the aircraft, the captain directed the first officer to notify air traffic control of the dual flameout. The crew extended the landing gear and flaps before performing a landing on the runway. The impact was described as a hard landing, which caused substantial damage to the airframe.
Findings
Subsequent testing of the engines at both idle and full power showed no operational anomalies. However, an inspection of the aircraft revealed that the engine controls featured an aftermarket throttle quadrant. Investigators found that the throttle quadrant idle stops and the power lever locking mechanism pins for both engines were worn. Furthermore, the internal springs for the left and right power lever locking mechanisms were found to be broken and worn.
Crucially, the investigation determined that the left engine power lever could be moved directly into the cutoff position without the need to release the locking mechanism first. While the right engine's lever still required the mechanism to be released to reach the cutoff position, the left lever's malfunction allowed for unintended engine shutdown. While a non-functional thrust reverser solenoid was noted on the right engine, it was not considered a factor in the event. No specific maintenance or repair procedures were available for the aftermarket throttle assembly, and no other mechanical issues were found that could account for the simultaneous loss of power.