"Have you tried turning it off and back on again?"

[George K]

Boeing 787s must be turned off and on every 51 days to prevent 'misleading data' being shown to pilots

The US Federal Aviation Administration has ordered Boeing 787 operators to switch their aircraft off and on every 51 days to prevent what it called "several potentially catastrophic failure scenarios" – including the crashing of onboard network switches.

The airworthiness directive, due to be enforced from later this month, orders airlines to power-cycle their B787s before the aircraft reaches the specified days of continuous power-on operation.

The power cycling is needed to prevent stale data from populating the aircraft's systems, a problem that has occurred on different 787 systems in the past.

According to the directive itself, if the aircraft is powered on for more than 51 days this can lead to "display of misleading data" to the pilots, with that data including airspeed, attitude, altitude and engine operating indications. On top of all that, the stall warning horn and overspeed horn also stop working.

This alarming-sounding situation comes about because, for reasons the directive did not go into, the 787's common core system (CCS) stops filtering out stale data from key flight control displays. That stale data-monitoring function going down in turn "could lead to undetected or unannunciated loss of common data network (CDN) message age validation, combined with a CDN switch failure".

Can you even buy a "dumb" airplane today?

[Horace]

They also need to remember to unplug the plane from the wall outlet before taking off. I once saw a plane dragging an airport wall section behind it as it taxied. That must have been mortifying.

[jodi]

Curious - How often to airplanes sit for awhile between flights - is there a rule about that? (And if so, why don’t they get turned off then?)

[Loki]

@jodi said in "Have you tried turning it off and back on again?":

Curious - How often to airplanes sit for awhile between flights - is there a rule about that? (And if so, why don’t they get turned off then?)

This reminds me of a funny saying we have in our house when something stops working, we say “let it rest a while”.

[taiwan_girl]

@jodi

@jodi said in "Have you tried turning it off and back on again?":

Curious - How often to airplanes sit for awhile between flights - is there a rule about that? (And if so, why don’t they get turned off then?)

I was thinking the same thing. LOL

Maybe @Copper has some ideas