FAA requires Boeing 777 software update to auto-throttle glitch

The Boeing 777 software will be updated by the Federal Aviation Administration with a previous software update that fixes an issue with the aircraft’s auto-throttle system. An Asiana 777-200ER crashed in 2013, and the FAA reports that a proposed airworthiness directive (AD) was released on June 22.

The FAA wants to mandate that US airlines replace the outdated Airplane Information Management Block Point software on the 777s. According to the FAA, the most recent update also fixes a different problem with the 777’s “wing anti-ice valve.” The proposal by the FAA would apply to 353 777s with US registrations, including 777-200 and 777-300 models. An inquiry for comments was not immediately answered by Boeing. In July 2021, the airframer released a service bulletin and an existing software upgrade. The FAA wants to make that update mandatory.

According to the FAA, a number of problems led to this decision. It states that an analysis of fleet data found 50 instances of wing anti-ice valve failure between November 2013 and March 2019 in the period. The FAA claims that because of such failures, hot bleed air can harm wing slats. The valve’s performance is tracked by the upgraded software.

In the update, the auto-throttle issue is also addressed. This issue was made public following the troubling 777 incident. While the auto-throttle was in the idle position upon landing, a pilot started a go-around. The auto-throttle should be deactivated when the throttles are advanced, however this is not quite completed. Instead it returned the throttles to idle, “creating a go-around during a low-speed condition.

According to the FAA, investigators determined that the 777’s “insufficient low-speed protection” was to blame for the crash. This software update “inadvertently expected to fail [auto-throttle] go-around during manual throttle advancement after disconnect,” according to the FAA’s paper. The FAAs claim that Boeing’s most recent version fixes the problem.