Pc-12 pilot reported on initial approach in IMC conditions and encountered severe turbulence and a d...

Narrative:

The flight was part 91 in a pilatus pc-12 flying to ZZZ.the flight proceeded normally. The weather at my destination ZZZ was marginal VFR with broken clouds at 2;100 feet and broken at 4;000 feet and 10 miles visibility. There were showers reported in the vicinity. Approach was vectoring me for an ILS. The closer I got to the destination airport and as we descended; I encountered increasing IMC. The radar showed green with some yellow. There was not a concern for wide areas of heavy rain that could not be circumnavigated. As we were descending to an assigned altitude of 9;000 feet; I encountered moderate turbulence. As I was reaching to disconnect the autopilot; we encountered a severe down draft that took me past my altitude and put the plane in a 45 degree roll to the right. The attitude and turbulence disconnected the autopilot before I had a chance to. My first concern was to regain a wings level attitude while slowing the aircraft and then stop the descent. By the time the plane was under control and the turbulence subsided to light/moderate; the altitude was estimated to be arrested around 7;700 MSL.at that point; approach asked to what altitude I was descending to. I explained what I encountered. He told me to 'just maintain 7;000 feet'.the rest of the flight to the ILS and eventually a VFR landing was uneventful.

Original NASA ASRS Text

Title: PC-12 pilot reported on initial approach in IMC conditions and encountered severe turbulence and a downdraft the disconnected the autopilot. The pilot recovered and made an uneventful landing.

Narrative: The flight was Part 91 in a Pilatus PC-12 flying to ZZZ.The flight proceeded normally. The weather at my destination ZZZ was Marginal VFR with broken clouds at 2;100 feet and broken at 4;000 feet and 10 miles visibility. There were showers reported in the vicinity. Approach was vectoring me for an ILS. The closer I got to the destination airport and as we descended; I encountered increasing IMC. The radar showed green with some yellow. There was not a concern for wide areas of heavy rain that could not be circumnavigated. As we were descending to an assigned altitude of 9;000 feet; I encountered moderate turbulence. As I was reaching to disconnect the autopilot; we encountered a severe down draft that took me past my altitude and put the plane in a 45 degree roll to the right. The attitude and turbulence disconnected the autopilot before I had a chance to. My first concern was to regain a wings level attitude while slowing the aircraft and then stop the descent. By the time the plane was under control and the turbulence subsided to light/moderate; the altitude was estimated to be arrested around 7;700 MSL.At that point; Approach asked to what altitude I was descending to. I explained what I encountered. He told me to 'just maintain 7;000 feet'.The rest of the flight to the ILS and eventually a VFR landing was uneventful.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1607619
Time
Date	201812
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	CA
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	PC-12
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 79 Flight Crew Total 10765 Flight Crew Type 3960
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Weather / Turbulence Inflight Event / Encounter Loss Of Aircraft Control

Pc-12 pilot reported on initial approach in IMC conditions and encountered severe turbulence and a downdraft the disconnected the autopilot. The pilot recovered and made an uneventful landing.