C-FEXH, a Cessna 208B aircraft operated by Morningstar Air Express, was conducting flight MAL7060 from Thunder Bay, ON (CYQT) to Winnipeg/James Armstrong Richardson Intl, MB (CYWG). During the descent from 10 000 feet ASL, the aircraft experienced moderate to severe turbulence. Severe turbulence was encountered at 6 000 feet ASL, as a downdraft caused a 2 000 to 2 500 feet per minute descent, with an associated airspeed exceedance.
The pilot did not have control over the rate of descent and informed ATC that the flight would be unable to maintain 3 000 feet ASL to the initial fix.
The subsequent landing was uneventful. The operator’s maintenance inspected the aircraft and no defects were noted.