Originally Posted by
A Squared
So what's your working theory here, that the articles about the 787's not making the switch as well an the picture of the PFD with the date of 1999 are all fake?
Smythe is partially correct. The bug is an initialisation problem only, however the affected GPS systems will not start up with the correct date. Without the correct date/almanac loaded the GPS systems will effectively be doing a cold start and it takes up to 15 minutes to download the full almanac from the GPS satellites (time to first fix), at which point they will show the accurate time and date for as long as they are online.
The reason the aircraft are grounded due to this problem is there a risk that if for any reason the GPS system had to be rebooted during flight it would take the GPS an excessively long time to get a first fix and come online.
https://en.m.wikipedia.org/wiki/Time_to_first_fix