Airlines are required by the EU aviation authority to reboot at least part of their A350 passenger aircraft every 149 hours at the latest. This was also warned about two years ago. These are a few systems that could otherwise have problems.
The European Union Aviation Safety Agency has issued a new, mandatory, so-called airworthiness directive, in which it states that airlines must perform a reboot on the ground every 149 hours at the latest. This is related to a software bug. This was already identified in 2017 and Airbus has a solution for it in the form of a number of software modifications. Airlines must either make the software updates or maintain the mentioned reboot cycles.
These software updates are already being implemented on some A350 Type 941 aircraft, but all other A350-941s of all serial numbers where they are not already are required to implement the system restart instruction. The Airbus fix concerns new software for the core processing input/output module and the common remote data concentrator. The latter system collects data from various sensors on board the aircraft.
EASA’s mandatory instruction takes effect on Friday and is intended to prevent a loss of communication between some avionics systems and the avionics network. Previous analyzes have shown that this can occur after these A350 systems have been switched on continuously for 149 hours. Several consequences have been noted, such as a ‘loss of redundancy to a complete loss of a specific function hosted on the common remote data concentrator and core processing input/output modules’.
This issue is not related to, but somewhat resembles an issue of the Boeing 787 Dreamliner. In 2015, a memory overflow bug was discovered on this also relatively new aircraft, which allowed the aircraft’s generators to shut down after 248 days of continuous use. This was caused by a software counter in the firmware of the generator control units. In the worst case scenario, this could lead to a complete loss of AC power, causing loss of control of the aircraft. At the time, the American regulator, the Federal Aviation Administration, issued an airworthiness directive for this problem.