Small Transport; Low Wing; 2 Turboprop Eng
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 20; Flight Crew Total 3200; Flight Crew Type 600
Other / Unknown
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; Flight Crew Returned To Clearance; Flight Crew Regained Aircraft Control; Flight Crew Executed Go Around / Missed Approach
Weather; Human Factors
Had lined up for the ILS 3 at OGD; but at glideslope intercept weather had dropped to 1/4 miles and 400 ft ceilings. Broke off approach and was vectored to the west to see if weather would move through. That didn't occur so we requested an approach to land SLC and were vectored to SLC ILS 34L. Approximately 10 miles downwind in solid IMC; autopilot and altitude hold on and about to turn base we hit a downdraft that dropped us approximately 2000 feet. Horizon ball was all brown; autopilot and altitude were ineffective; the loss of control set off the master warning system due to lack of fuel (at the time we had 750 lbs per side); and the terrain warning went off. Recovery was accomplished; but with a 2000 foot gain (assigned altitude 10000 at the floor of incident approximately 8000 at the ceiling of incident approximately 12000). I was then routed back to the west and north on vectors for sequencing back to the ILS 34L SLC that was shot with a side step on final in VFR conditions to RWY 34R. During taxi in I was instructed to contact SLC TRACON by phone; which I did and he asked what had occurred and I relayed a shorter version with not as many facts. He was very polite; professional; and understanding.
Light twin pilot reported encountering severe turbulence and windshear on downwind for the SLC ILS Runway 34L at 10000 feet in IMC. 2000 feet was lost and a terrain warning was received along with a master warning for fuel pressure before control was regained.