[tz] GPS Week Number Rollover Apr 6/7

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Fri Apr 12 14:37:34 UTC 2019

On 2019-04-10 07:45, Brian Inglis wrote:
> On 2019-04-03 16:56, Chris Woodbury via tz wrote:
>> The airlines' software problems are most likely with Notices to Airman (NOTAMs).  These are
>> public domain data and announcements of airspace restrictions, etc. which AeroData, Inc. has
>> been contracted by the FAA to provide since 1990.  It looks like they do it for the EU, too.
>> These announcements are part of the suite of software that AeroData provides.  Every media
>> outlet is mentioning weight and balance (read fuel load and cargo balancing for aircraft before
>> take off) and completely missing the part that does airspace restriction, route and waypoint 
>> calculations that will certainly involve GPS information.  Ya' gotta love the media...
> Looks like impacts appears to have been limited to unupgraded TomTom, Garmin,
> and Boeing devices, including at least 16 KLM and Chinese airlines' 777 and 787
> Dreamliners with Honeywell flight management and navigation software:
> https://thenextweb.com/tech/2019/04/08/mercifully-the-gps-millennium-bug-was-a-massive-letdown/
> https://arstechnica.com/information-technology/2019/04/gps-rollover-apparently-cause-of-multiple-flight-delays-groundings/
> https://simpleflying.com/boeing-787-china-grounding/

More issues noted in comp.risks Risks Digest http://risks.org/ 31.18 2019 Apr
http://catless.ncl.ac.uk/Risks/31/18 plus mentions of Boeing's issues above.

"On 6 Apr 6, something known as the GPS rollover, a cousin to the dreaded Y2K
bug, mostly came and went, as businesses and government agencies around the
world heeded warnings and made software or hardware updates in advance.

But in New York, something went wrong—and city officials seem to not want
anyone to know.

At 07:59pm EDT on Saturday, the New York City Wireless Network, or NYCWiN,
went dark, waylaying numerous city tasks and functions, including the
collection and transmission of information from some Police Department
license plate readers.

The shutdown also interrupted the ability of the Department of
Transportation to program traffic lights, and prevented agencies such as the
sanitation and parks departments to stay connected with far-flung offices
and work sites."


"Many of the world's older GPS devices had a Y2K moment on 6 April.  Devices
made more than 10 years ago had a finite amount of storage for their date
accounting system, and that number maxed out on Saturday, 6 April.

Nineteen National Oceanic and Atmospheric Administration (NOAA) coastal and
marine automated stations were not updated to mitigate the issue, and those
stations are out of commission until workers can service them on
location. The outage has the National Weather Service (NWS) office in
Anchorage, Alaska, hurrying to fix their downed stations before bad weather
comes in this week."


Previous articles http://catless.ncl.ac.uk/Risks/search?query=GPS+rollover
including 22.94 2003 Oct The Earth's not slowing down fast enough to suit
Motorola (Paul Eggert) http://catless.ncl.ac.uk/Risks/22/94#subj3 illustrating
256 week offset and leap second problems.

Risks Digest issue 17.86 1996 Mar has many articles related to leaps in time

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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