EMB-145 flight crew reported temporary loss of aircraft control and a passenger injury resulted from encountering severe clear air turbulence during cruise.
Synopsis
EMB-145 flight crew reported temporary loss of aircraft control and a passenger injury resulted from encountering severe clear air turbulence during cruise.
Narrative
On Day 0; flight #ABCD ZZZ to ZZZ1. While en route at about XA:30-XA:35 at 17;000 ft (just west of ZZZ [VOR]) we hit severe clear air turbulence where the aircraft began abrupt changes and uncommanded VS descent of ~2500fpm dropping us about 500 feet in altitude. We were trying to slow prior to hitting pocket of severe bc there was constant light chop with occasional moderate but while the uncommanded descent was initiated the airspeed trended/fluctuated to almost over-speeding popped momentarily to the red and then back down to 250. The autopilot stayed engaged. We immediately reported severe turbulence to ATC- advising we need immediate lower. We hit another pocket of severe followed by continuous moderate until we began initiating a descent intentionally. All 3 crew members noted coming up out of their seat. A passenger (tall) hit their head on the ceiling; cracking the ceiling. The FA was seated the entire time and the seatbelt sign was on. We were notified of the injured pax when we were beginning our approach to land by the FA and at that time he said he didn't want medical attention; but we went ahead and asked tower to have medical waiting for us. We notified ops via ACARS and spoke to Maintenance while on the ground.There was nothing to prevent the occurrence. There was no projected turbulence or weather along our route of flight.
Second reporter narrative
During cruise; just prior to anticipating our initial descent; at 17;000 feet; just west of ZZZ [VOR]; we experienced severe turbulence. I reduced the power and our speed tape showed a trend to the redline. We were at 270kts increased to about 300kts and eventually came back down to 250kts. Although the auto pilot stayed on and engaged in LNAV and ALT; we had an uncommaned descent of 400-600feet. The vertical speed trend showed a descent of 2;500fpm. The FO immediately told ATC we were in severe turbulence and needed to descend. I contacted the flight attendant and she was already seated. I had already mentioned light turbulence procedures were in effect during the crew briefing. We asked each of the controllers along our way for ride reports and nothing worse than light chop was reported. The weather prior to departure only showed light turbulence south of our route and no where on it. All of our arrival prep was already completed; so we proceeded to make an approach and landing. As we were joining the approach; the flight attendant informed me a passenger (tall) had hit his head on the overhead bin/ceiling and there was no bleeding. We asked ATC to have medical personnel at the gate and there was; then he was cleared and didn't go to the hospital. Dispatch was notified of the severe turbulence via ACARS and then of the name and seat number of the injured passenger. We noted that all three crew members came up out of our seats during the severe turbulence and upon inspection; the overhead bin was cracked/damaged from the passengers head making contact. The seatbelt sign was on for the duration of the flight.Suggestion: Follow our training and manuals.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.