FAA 2019-08-51 (Emergency)

Requires replacing the angle-of-attack (AOA) sensors with improved AOA sensors before further flight. Prompted by three incidents where the stall warning and protection system (SWPS) or Electronic Stability & Protection (ESP) system engaged when not appropriate. According to the FAA, “Potential erroneous AOA derived indications may occur before, during, and after unintended automatic control system engagement. These indications include an abnormal appearing low speed red band or Vref green donut presented on the airspeed tape. Failed indications or intermittent indication may result in one or more of the following: unintended automatic flight control activations; the flight crew having difficulty controlling the airplane; excessive nose-down attitude; and/or possible impact with terrain.”