Originally Posted by
ATC Watcher
Thanks , in the meantime I found this explanation in another bulletin :
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Intresting times...
That’s always been the case and is known by crews…..you can deselect ( inhibit ) the GPS on the FMC’s easily and they’ll come back to the IRS position mix or radio updated position mix…..might take a few minutes to come back though depending how far they drifted. In the mean time advising ATC and using basic modes.
The clocks will go crazy perhaps until the crew reset them to manual against their watch then the FMC’s will show correct time predictions again. LNAV and VNAV will be available as long as ANP is ok for the stage of flight, look ahead terrain monitoring and ADSB reporting won’t be. No biggie.