C-GGGQ, a B200 Beech King Air aircraft operated by Miccar Aerial (dba Good Spirit Air Service), was conducting flight GT1128 from Prince Albert (Glass Field) (CYPA), SK to Yorkton Muni (CYQV), SK with only the 2 pilots on board. During the descent through 12 000 feet approximately 40 nm north of CYQV, the flight crew noticed fluctuations in the fuel flow and gas generator speed (ng) for the left engine (Pratt & Whitney Canada PT6A-42). As the flight continued in the descent, the left engine parameters returned to normal, then followed by a dramatic engine rollback. The flight crew feathered the engine, noticed an increase in ITT, and performed a precautionary engine shutdown. The aircraft landed without further incident in CYQV with emergency services
The operator’s maintenance replaced the fuel control unit.