Boeing 787s must be turned off and on every 51 days
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Boeing 787s must be turned off and on every 51 days
According to https://www.theregister.co.uk/2020/0...ys_stale_data/ "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 FAA directive is here https://ad.easa.europa.eu/ad/US-2020-06-14, and comes into effect on Tuesday 7th April 2020
The FAA directive is here https://ad.easa.europa.eu/ad/US-2020-06-14, and comes into effect on Tuesday 7th April 2020
Interesting.
Given that some 787s haven't flown for nearly a year now as a consequence of the Trent 1000 problems, one wonders why this issue appears only to have surfaced now ?
Given that some 787s haven't flown for nearly a year now as a consequence of the Trent 1000 problems, one wonders why this issue appears only to have surfaced now ?
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According to https://www.theregister.co.uk/2020/0...ys_stale_data/ "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 FAA directive is here https://ad.easa.europa.eu/ad/US-2020-06-14, and comes into effect on Tuesday 7th April 2020
The FAA directive is here https://ad.easa.europa.eu/ad/US-2020-06-14, and comes into effect on Tuesday 7th April 2020
There was also a previous 787 AD in 2015 which related to a loss of AC power after a counter overflowed.
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I would bet that this issue is caused by an incorrect garbage collection of disused packets in CCS.
I wonder is this is another bug from Wind River Systems (the company selling VxWorks) or if the bug only touches the customisation that Honeywell made for Boeing.
I wonder is this is another bug from Wind River Systems (the company selling VxWorks) or if the bug only touches the customisation that Honeywell made for Boeing.
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It looks as though the guy who computed that used a standard round rather than a round down for the day count calculation.
The correct value is:
2^32 ms = 49d 17h 2m 47s 296ms
The correct value is:
2^32 ms = 49d 17h 2m 47s 296ms
It was me :-) I just used Excel and trusted some number on intertubes for the number of secs in a day. I won't be flying on one so was a bit slapdash.
Edited - AH! Penny dropped. I accepted the whole number of days but of course Excel rounded it up.
Edited - AH! Penny dropped. I accepted the whole number of days but of course Excel rounded it up.
A common tick counter period in real-time systems is 1.024 ms (don't ask me why!). That works out at 50.9 days.
Way back when, the odd student co-op student would want to see how long it took to overflow a 32 bit register by bumping it by one. The time would of course double adding unsigned.
At about 5 microseconds per Add and Branch on a '70s mainframe times 2^32 you could be looking at some 20,000 seconds which will be a few hours.
At about 5 microseconds per Add and Branch on a '70s mainframe times 2^32 you could be looking at some 20,000 seconds which will be a few hours.
Rember this?
The new US stealth fighter, the F-22 Raptor, was deployed for the first time to Asia earlier this month. On Feb. 11, twelve Raptors flying from Hawaii to Japan were forced to turn back when a software glitch crashed all of the F-22s' on-board computers as they crossed the international date line.
a software glitch crashed all of the F-22s' on-board computers as they crossed the international date line.
Another one worked fine for a couple of years but could not handle the next leap year that came along for any payments initiated before February 29th that were due afterwards.
One accounting system I was involved with started to lose large numbers of transactions. Eventually traced to an internal counter that went up to 9999, but that was proving insufficient so it was increased - everywhere but in one place, so while everything else moved on from 9999 to 10001, this went to 0001 and started overwriting the initial items.
Power down... power up...
I would say that most pilots who have flown the 320 series for any period of time would hav seen or been asked my maintenance to do the power down.
In 10k hours on the baby bus, 3 times comes to mind, 2 reset the issue and the 3rd was never going to work!
Ahhh computers, software...
Now where is that old Cessna and the 6 pack?
I would say that most pilots who have flown the 320 series for any period of time would hav seen or been asked my maintenance to do the power down.
In 10k hours on the baby bus, 3 times comes to mind, 2 reset the issue and the 3rd was never going to work!
Ahhh computers, software...
Now where is that old Cessna and the 6 pack?
