ERJ-170 flight crew reported encountering wake turbulence on descent into ORD that resulted in a minor injury to a Flight Attendant.
Synopsis
ERJ-170 flight crew reported encountering wake turbulence on descent into ORD that resulted in a minor injury to a Flight Attendant.
Narrative
We were flying to ORD; and started our descent on the WYNDE2. ATC told us to cross RHIVR at FL200; as we descended through around 22-23000 ft; we felt a jolt of moderate chop. It wasn't that bad; but we knew from the feeling it was wake turbulence. It rolled us into maybe a 10 degree bank or so. I disconnected the autopilot; turned left of course some to get on the upwind side of the aircraft's wake in front of us. The turbulence stopped within 2-3 seconds. It wasn't that bad; it was moderate chop at the worst. We told Center about the wake encounter; and told them we are offsetting the STAR the rest of the way down to avoid the aircraft's wake. About 10 minutes later or so; FA (Flight Attendant) called the flight deck and said [another] FA hurt his knee from the turbulence. I asked her to have [that FA] call us. He told us that during the turbulence; he hit his knee awkwardly. He said he can still walk fine; but his knee was hurting some. I asked if he needed medical assistance at the gate; and he said he didn't think he needed it at first. He said he didn't want a lot of people looking at his leg; and told me again he could walk so he was okay. I told him to look at his leg in the bathroom; and if you need medical attention; please let us know so we can make the arrangements. He never called us back in flight (only about 20 min or so until we landed from time of incident). After we landed (still taxiing in); we called the FA's to make sure he was okay; and he said he might need medical attention but was unsure and didn't want a lot of EMS to meet us at the gate. At this point; First Officer and myself made the decision to get medical staff to meet us at the gate. We told Ground about what happened; and they coordinated with EMS for us. We also told Ops to make sure they knew about the situation and to get us a new gate that was available. Once at the gate; EMS was waiting for us; and they went all the way to the back of the aircraft to check on [the] FA. We deplaned as normal while they talked with him. After they did their medical exam; they concluded he just bruised his knee and might have some small swelling later on. FA did not want to go to the hospital after hearing what EMS had to say. I told FA if he needs to call off the trip; he should. He said he was okay to continue the trip and keep working. I called our Dispatcher to let her know what happened. We received a phone call number from ATC; and I called them after letting them know more details about the event and that FA was okay.Suggestions: Increase spacing requirements for aircraft on the same route.
Second reporter narrative
The flight was smooth from the moment of takeoff through the enroute phase of flight. After preparing the flight deck for arrival and landing; we we're assigned to increase to 300 knots for spacing. As we were descending we started to notice we were right behind the aircraft ahead; but the air was still smooth and no reports heard of anything worse. Once we were descending to cross RHIVR at FL200 somewhere around FL240-FL220 we hit a pocket of wake turbulence that was enough for the Captain who was Pilot Flying to disengage the autopilot and deviate to the left and below the wake where it immediately became smooth again. The jolt felt like the equivalent of moderate chop but nothing worse and really was not bad as it lasted just for two or three seconds; but we decided to stay offset to the left to avoid the reoccurring wake if we got back on the arrival and ATC approved the offset. FA (Flight Attendant) called us about 10 minutes after to inform that [another] FA hurt his knee. At this point the Captain asked if he needed medical attention upon arrival but said he was fine and could walk; but was just hurting and didn't want a lot of attention. We then called up a few minutes later to ensure everything was alright and that is when [he] said he was still OK and we said to let us know if anything changes and to call back regardless of sterile light. After landing we then called back again since we didn't hear back and [he] said he looked at his leg in the lavatory and said he was cut up but was still unsure if he needed assistance. At this point the CA (Captain) and I made the decision to make ATC and Operations aware of the situation so we could have medical personnel meet us at the gate. Upon arriving at the gate EMS boarded the aircraft and went to the aft to inspect [the FA] where they said he would have at most a bruise and maybe swelling. After everyone was deplaned and medical personnel exited he said he could finish the trip.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.