According to the European Aviation Safety Agency (EASA), a software problem could lead to loss of elevator control for certain Airbus A350 aircraft.
The directive issued last May 5 by EASA, warns operators of Airbus A350-900 and -1000 aircraft to amend their applicable AFM (aircraft flight manual) and Minimum Equipment List due to a software problem that could lead to loss of elevator control.
"An occurrence was reported in which PRIMary flight control computers (PRIMs) indicated that both elevator actuators were found to be defective." EASA also states that further investigation revealed that incorrect instructions were implemented with the introduction of the "PRIM P13standard," which is part of the Flight Control and Guidance System (FCGS) X13 standard.
Since the effective date for resolution of the problem was immediately set for the following days, EASA also required operators to change their applicable AFM, subject to a temporary update and revision. The EASA directive also states that they must "inform all flight crews and thereafter operate the aircraft accordingly." The affected operators must also amend the Airbus A350 Master Minimum Equipment List (MMEL) accordingly. This is a directive that is considered to be an interim action, which means that further actions may take place in the coming days.
Interestingly, this is not the first software bug related to the Airbus A350. In July 2019, some models of the A350-900 had an aviation problem, which could be fixed by a software update, or even by turning the aircraft off and on at least once every 149 hours. Performing this rudimentary action would have prevented "partial or total loss of some aviation systems or functions."
The original article via Simply Flying can be read at: