Fortunately the fix is as simple as turning the plane off and turning it on again which is the advice which comes from TV’s IT Crowd.
If the pilot leaves the plane switched on for 248 days, and the keys are in the ignition, a software glitch will put the plane into a failsafe mode.
We say failsafe, it is more of a euphemism for “bricked”. The plane will lose all of its power, the generator control units (GCUs) will shut off, leaving the plane without power and loss of control of the plane.
While this is a problem if the plane is on the ground, it is a megadisaster if the plane is flying. There are a lot of ifs which make the event unlikely.
“If the four main GCUs (associated with the engine mounted generators) were powered up at the same time, after 248 days of continuous power, all four GCUs will go into failsafe mode at the same time, resulting in a loss of all AC electrical power regardless of flight phase,” the directive warns.
Boeing is working on a software upgrade that will address the problems, the FAA says. Boeing found the problem during laboratory testing of the plane. The problem has only occurred in the lab and that all of the planes in service are turned off and on again as part of regular maintenance.
It is the latest problem to hit the plane, which is also said to be vulnerable to hacking attacks and to have seen difficulties with batteries catching fire. Such problems have seen the planes grounded, though they were returned to service shortly after.
Over 250 of the planes have been built, and they are used by companies all over the world.