B737-800
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
General Physical Injury / Incapacitation
Environment - Non Weather Related; Procedure
On approach to Runway 26; outside the final approach fix; with autopilot engaged at around 3000ft. The aircraft exhibited an uncommanded roll to the right followed by an immediate roll left which we attributed to wake turbulence from the preceding A321. Both rolls were excessive but I am uncertain of the bank angle that was reached. After the roll left the Captain as Pilot Flying disengaged the autopilot and continued the approach and landed without further incident. It was soon after landing that we were informed that the #2 Flight Attendant was out of her seat in the rear galley and was injured during the event. Wake turbulence is difficult to predict especially without sufficient warning. We discussed the fact that a quicker disconnect of the autopilot to arrest the roll sooner may have helped. Also we were surprised at the fact that a Flight Attendant would be standing at that point in the flight.
At approximately FAF; the aircraft banked sharply. I turned off the autopilot; leveled the wings and resumed the visual approach and landing. On taxi-in; the flight attendants called on the intercom and said that the a Flight Attendant was injured. We called Operations and requested paramedics meet us at the gate. We asked Tower what aircraft we followed and were told that it was an [A321] and that they sometimes have more wake turbulence than a heavy. Tower asked if we had the aircraft in front of us in sight. First Officer said that we did. We changed runway FMC data for the third time after being cleared for the visual approach. PHX Tower should plan on ILS approaches at night unless pilot requests a visual approach. This would increase safety and separation.
B737-800 flight crew reported a Flight Attendant was injured during a wake turbulence encounter on approach to PHX in trail of an A321.