Small Aircraft; High Wing; 1 Eng; Fixed Gear
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 200; Flight Crew Total 1200; Flight Crew Type 500
Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter VFR In IMC
Air Traffic Control Provided Assistance; Flight Crew Regained Aircraft Control; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification
Weather
A VFR flight was to be flown from BFL to ZZZ for the purpose of repositioning an aircraft for company business the following day. This flight was operated under Part 91 pursuant to all applicable FAR's and company SOP's. The intended route took the pilot from BFL to ZZZ2 to ZZZZZ to ZZZZZ1 then direct ZZZ at an altitude of 9;500. The pilot obtained a briefing via Foreflight at XA:21 local time for an intended departure time of XA:45. Upon reviewing the briefing; it was decided current conditions would allow for the safe operation of the flight. The pilot departed BFL at XA:45 local time and climbed straight out in VMC conditions to an altitude of 095. Cloud conditions in the valley were broken at various altitudes below 8;000 feet. As the flight progressed towards ZZZ2; the pilot then proceeded direct to ZZZ3. As the pilot approached the ZZZZZ2 intersection; traffic could be viewed on ADSB traveling opposite direction on the V197 (Northwest) at 10;500. This traffic was indicating a ground speed ranging from 50-70 knots confirming the PIC's suspicion of stronger than forecasted winds aloft. As the pilot continued southeast bound; it was apparent that the cloud conditions below and ahead were worsening and the PIC initiated a climb to 11;500 MSL. upon reaching 10;300 MSL just south of ZZZZZ3 intersection; the pilot turned east to avoid building clouds. During this moment; the pilot encountered a 2;000 FPM downdraft which they countered with a pitch up attitude to achieve Vy. Once established at Vy; the rate of descant had slowed to 700 FPM. Knowing conditions improved to the west; the PIC initiated a turn back to BFL and informed ATC of the intentions as well as the conditions. Upon receiving a handoff to BFL Approach; the pilot informed them of their intentions and that it may be necessary to notify ATC. As the ground speed began to drop below 45 knots still in a descent at Vy; the PIC saw a situation where the aircraft would not be able to stay above the cloud layer and safely away from rising terrain to the west. The PIC then informed ATC that they were turning southbound; notified ATC due to weather and squawked 7700. As this decision was made; the PIC was experiencing a severe downdraft where positive control of the aircraft's altitude was difficult to maintain. Upon descending to an altitude of 6;500' MSL; the pilot encountered a large updraft and used this to climb to an altitude of 12;00 MSL which allowed exceptional terrain separation. The pilot flew southbound; where it was visibly better weather and began to request PIREP's from ATC for a VFR field east of the terrain knowing that the area east offered high ceilings and lower terrain. ATC informed the pilot of a large hole in the cloud layer on a 090 heading and suggested the pilot land WJF. ATC then asked the pilot if they were able to accept a 090 heading and it was accepted. The pilot then sighted the large opening; measuring roughly 25-30 nm x. 5 nm and began a decent in VMC conditions. As the pilot descended below the surrounding cloud layer's bases (5;700 feet MSL); they verified ZZZ4 in sight and were given a handoff. Upon assessing the situation; the PIC decided against landing at ZZZ4 and determined an emergency declaration was no longer needed; relayed intentions to ATCT at ZZZ4 and were handed back to Joshua Approach. The declaration was canceled with them and the flight continued to ZZZ1 for a safe landing. Upon landing; the PIC contacted the Director of Safety for the company and informed them of the events that occurred. It was decided that the pilot made appropriate inflight decisions to ensure the maximum safety of flight. Further reviewing the events that took place; the pilot decided to reread the briefing to determine if any significant signs of these conditions were missed. No information was found to be omitted during the PIC's decision to conduct the flight. Numerous other aircraft had flown the same area throughout the day and encountered conditions well within the PIC's comfort; conditions were not reported outside of VFR regulations at departure; or at arrival. The only adverse weather reported was IFR at TSP to the north east of the intended route and winds aloft in that area in excess of 45 Knots. Going forward; the PIC will study material specific to the safe operation of a single engine aircraft over mountainous terrain to better be able to determine when such adverse conditions may be found and what to do differently when they are encountered. An action that could have been utilized by the PIC that was not was to request an IFR clearance east of the position where it encountered the first sign of severe downdrafts and flown via radar vectors to an area that was VMC away from rising terrain.
General Aviation Pilot reported encountering turbulence and downdrafts which exceeded aircraft capability and controllability; resulted in emergency divert.