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Old 2nd Feb 2017, 17:20   #1 (permalink)
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A320 elapsed time counter issues in February only

Hello:

today I noticed the counter was acting funny (scrambled digits, showing 72 minutes etc) so I checked the MEL (see attached).

Why is this only an issue in February??

Thank you
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Last edited by olbie; 7th Feb 2017 at 17:24. Reason: Spelling
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Old 2nd Feb 2017, 19:19   #2 (permalink)
 
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Didn't that happen in February last year ?
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Old 3rd Feb 2017, 04:01   #3 (permalink)
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Not sure Dave I only became aware of this yesterday. Can't find anything using the Search function...
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Old 3rd Feb 2017, 10:11   #4 (permalink)
 
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Last year we had a note about it on our intranet - unfortunately it was removed...if I remember correctly it was attributed to the leap year, but obviously this can not be the cause, considering that is is happening again this year...could still have something to do with the different number of days in February compared to other month. It seems to be a common issue now, had it a couple of times last year and already twice this year...at least the clock is not that important (a note that the company issued this year assures us that the GPS time used by the systems is not affected, its only the chrono itself...they cautioned however that it could cause Datalink issues)
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Old 3rd Feb 2017, 10:48   #5 (permalink)
 
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Last year (2016) some problems occurred due to time signals sent by one GPS satellite.
GPS error may have caused digital clock errors -
I haven't heard anything about this year's problem.
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Old 3rd Feb 2017, 15:10   #6 (permalink)
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You should get AIRBUS OIT from your technical pilot
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Old 5th Feb 2017, 16:48   #7 (permalink)
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Thanks a lot, that covers it!
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Old 7th Feb 2017, 08:23   #8 (permalink)
 
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And it's not just Airbus clocks that suffer. The curious question is what sort of rinky-dink coding is used in the clock's software? After all, it's just a clock yet somehow a month value appears to upset the display, possibly a shortcut to deal with February's unique day count. It certainly shows a failure in the testing process for the clock's software. I just hope other more important software is tested to higher standards.
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Old 7th Feb 2017, 08:30   #9 (permalink)
 
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Quote:
Originally Posted by Piltdown Man View Post
And it's not just Airbus clocks that suffer.
Can you give some examples of where else the issue manifests itself ?
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Old 7th Feb 2017, 12:00   #10 (permalink)
 
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Old 8th Feb 2017, 06:53   #11 (permalink)
 
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Quote:
The curious question is what sort of rinky-dink coding is used in the clock's software? After all, it's just a clock yet somehow a month value appears to upset the display, possibly a shortcut to deal with February's unique day count.
Yup, wrong leap year calculation. The affected year ranges all start with powers of 2 from the year 2000: 2016, 2032, 2048, 2064. (All leap years). And the ranges are all multiples of 4 years (2016-2019, 2032-2035, 2048-2055, 2064-2071).
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Old 8th Feb 2017, 07:29   #12 (permalink)
 
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Er, since when was 48 a power of 2 ?
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Old 8th Feb 2017, 17:26   #13 (permalink)
 
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2^11 = 2048
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Old 8th Feb 2017, 18:27   #14 (permalink)
 
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True, but that's not what the OP was talking about.

If it helps, I'll rephrase my question: Since when were 2016, 2032 and 2064 powers of two?

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Old 12th Feb 2017, 09:03   #15 (permalink)
 
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An example: not long after departure yesterday our airborne was 10:0B, shortly after 10:0F. Not long after, total gibberish, then it reset itself. This also occurred on the ground as well just before another reset. The Zulu time display always appears to be OK but the stopwatch corrupts itself every now and again.
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Old 1st Feb 2018, 19:46   #16 (permalink)
 
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Saw it today in an A321. Last digit initially went to - and when it decide to behave itself it added seven hours to the elapsed time.

Last edited by tubby linton; 6th Feb 2018 at 15:34.
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Old 1st Feb 2018, 23:08   #17 (permalink)
 
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And we're talking autonomous airliners for the future?
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