Airliner 99
Distraction; Physiological - Other; Workload; Situational Awareness
Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Weather
On a relatively calm and clear day at ZZZ1; I departed southbound toward ZZZ. The takeoff was uneventful; I contacted Approach for flight following. Throughout the climb to 9;500 ft.; there was constant light to moderate turbulence; typical for this segment of flight throughout this area. Upon reaching cruise the severity increased to consistent moderate turbulence; again not abnormal for the route of flight; the aircraft was slowed. I reported the ride conditions to Approach; and they stated that a Cessna 208 had reported similar conditions and opted for lower. The airplane began to experience downdrafts; exceeding over 1000 fpm and airspeed fluctuations of +/- 20 knots. I elected to descend to 7;500 ft. based on the ride conditions reported by the aircraft in front of me. At 7;500 ft. I experienced consistent moderate to severe turbulence; with consistent up and downdrafts; accompanied by fluctuations in airspeed. Occasionally; I nearly hit my head on the ceiling of the airplane. I queried [ATC] and they stated that the aircraft had reported a better ride at 6000 ft.; at that time I descended to 6000 ft. At 6000 ft. the ride was much more manageable; and I was able to make it to ZZZ safely. I made the decision that the airplane did in fact fly through severe conditions and required an inspection. I wrote the airplane up and contacted Maintenance Control. The unstable nature of the valley I was flying over and the absence of weather reporting in the valley make it difficult to gauge the ride conditions. I should have slowed the airplane down; and descended to more manageable flight conditions.A solution would have been flying the airplane above the valley to avoid possible severe turbulence. I talked with my pilot supervisor and he advised that flying at 15;500 ft. over the valley is a viable option. This particular route is very abnormal; with respect to mitigating risk. This is a prime example of how quickly things can change when flying. The more we can do to try to mitigate these risks as a whole; the safer it will become.
Beechcraft 99 pilot reported flying through severe turbulence.