View Full Version : International Date Line Air Data Computer Bug
Date Line Bug
Something the Flight Testers missed.
Heartell that some very modern hardware was recently carrying some very modern software across the International Date Line from east to west. The software found itself to be incapable of resetting its date forwards through 24 hours and went belly up. Very embarrassing!
Are there any other known similar occurrences - say with INS sytems or whatever?
Shawn Coyle
23rd Feb 2007, 19:56
it wouldn't be on the latest wonderjet fighter would it?
Wonder how it will handle leap years or the dreaded GPS date changeover....
Shawn Coyle
You picked it!
Tell us more about the GPS date changeover please.
Shawn Coyle
24th Feb 2007, 14:22
Somewhere around the Y2K shambles, someone mentioned that the GPS rollover problem could be even worse. Memory being what it is, I can't remember it all, but it had to do with the GPS clock only being able to run till some date and then 'rolling over'. Only so many digits available in the clock memory it seems.
Can't remember when that was supposed to - maybe it happened already and nobody noticed!
Matthew Parsons
24th Feb 2007, 16:31
GPS counts weeks and only has 10 bits. Every 1024 weeks that number resets. It happened in 1999 and as far as I know there was little if any effect.
khorton
26th Feb 2007, 19:51
Supposedly the first time a certain large North American country with a small air force tried to do a live missle (Sparrow?) firing from its newest fighter type at its test range, it was discovered that said missile would not fire. Apparently there was a software fault in the aircraft's fire control software, such that missles could only be fired if the aircraft's heading was in a certain range. The range of headings that worked matched the axis of the weapons test range where the manufacturer and the first customer had done their testing. Fortunately this was discovered well before said aircraft was ever put in harm's way.