87
cho-uc
1y

# Now I am afraid to fly ... 😐https://theregister.co.uk/2020/04/...

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@FrodoSwaggins
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@Root was gonna comment something about him lol
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That was just Boeing's warm-up for the 737 max.
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That kind of sounds like Y2K. Can someone explain why it matters (if it does)?
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@kamen You have two ways of checking time intervals with unsigned integers: one doesn't work upon roll-over, and one does. Boeing went for the first option - typical noob mistake.
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@kamen

2^32 = 4,294,967,296
51 * 24 * 60 * 60 * 1000 = 4,406,400,000

I am not an expert in aviation, but it probably works like a mileage car log.
Thus "display of misleading data" to the pilots, with that data including airspeed, attitude, altitude and engine operating indications.
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@cho-uc It's the internal system time in microcontrollers, driven by its timer interrupt. Basically just a 32 bit unsigned int with the milliseconds since power-up of the component.

You need that for all sorts of time intervals like "check that this switch here has been pressed for at least 5 seconds" or "switch this motor here on for 3 minutes".
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I know nothing about planes - but are they usually left "on" for 51 days?! I would have thought they'd be powered off each night if they weren't being used. Or do they work more like a car battery in that they're always on standby?
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@AlmondSauce That's what Boeing maybe thought, too. On the other hand, aircraft are being cleaned and maintained at night so that they don't get to sleep that much.

If there even is a night on ground, that is - if you fly e.g. Delhi-London in the evening, you arrive in the morning.
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@Fast-Nop I'm still wondering if it's an issue at all for that reason - I get not all planes would have a rest each night, but more than a month without ever having a rest?! That seems a bit much.

There's massive problems at Boeing, definitely. But the register is kind of the idiotic tabloid of the tech world which loves to publish crap... so I'm really not sure whether it's a big problem or not.
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@AlmondSauce Of course the engines won't be running 24/7, but if it's powered via ground power plug or battery, the computers keep running.

Especially in cold climate, you don't want to leave it standing in the night because it takes quite some time to warm everything up again.

Also, in avionics, you can't just say "most aircraft get switched off". If this is mandatory for safe operation, there has to be a well-defined process for that to make sure airlines actually follow that.
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@Fast-Nop Well yeah, they can't have the engines on all the time, but running APU constantly is also quite wasteful and probably expensive. I'd imagine they have to cycle power as part of maintenance routine anyway. I'm also pretty sure that Boeing made it a mandatory in the service manual to avoid liability.
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Every minute costs, so airlines want their planes as much as possible in the air. they want the downtime as low as possible, since it needs time to boot an plane. If an onboard system on an train needs less than two hours to boot up, and trains have much less computers than airplanes today, an modern 787 would need much more time, since it has many computers that depend on each other.
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@stop What the heck, which train needs two hours to boot up?
I have seen multiple reboots of different trains and all of them were up running in less than a minute, most of the time it was only a matter of seconds.
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Well That sounds bad and all, but let's focus on the important thing, here: I hope they were able to save money thanks to that little thing. Right...?
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Sounds a bit like the integer overflow of the esa rocket a-something, a similar fuck up that resulted in a crash because the trajectory got messed up
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Some friends of mine are aircraft maintenance engineers, they never fly anywhere for leisure..

They said to me, if you knew, what we knew, you wouldn't fly either !

Basically it comes down to management making decisions to save money..

But I guess you can't run an airline at a loss..
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@matt-jd The rocket integer overflow was different because that was a bug in itself. With the system timer, overflow itself isn't a bug, that's just the normal wrap-around - the bug is in mishandling that.
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@Benedikt some german trains frim bombardier buyed by the DB.
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Now just need some friends who are ship maintenance engineers..

https://rivieramm.com/news-content-...
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There’ll be a lot of time for them to rest now with the pandemic. Laid to rest.
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@Fast-Nop as I first read your 'does not work doing rollover' I first imagined a clock that stops working when the plain does a barrel roll.. Rip.