FAA 2020-18-51 (Emergency)

Requires, before further flight, revising the airplane flight manual for any aircraft with the Sandia SAI-340A or BendixKing KI-300 solid-state attitude indicator to prohibit operation under IFR or night VFR and prohibit coupling the autopilot with an affected attitude indicator. Prompted by a report of three failed attitude indicators and a follow-on investigation that found a total of 54 failed attitude indicators. The effect of the failure was erroneous attitude data provided to the pilot and autopilot, if equipped. According to the FAA, pilots might not be able to determine when data from the attitude indicator is erroneous or unreliable.