Re: Y2K - sources of info

Date:         07 Jan 97 07:20:18 
From:         Edward Hahn <>
Organization: The MITRE Corporation
References:   1
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S.L. wrote:
> Sorry if this has been discussed in the past, but is there any source
> of information on to what extent the aviation industry might be
> exposed to the Y2K issue? I was thinking in terms of ATC, onboard
> systems, etc.

Actually, I was listening to an NPR report on the Year 2000 date
encoding issue (i.e. Y2K) with my wife (we're both aviation engineers -
I'm more avionics oriented and she's more ATC oriented); the "expert"
mentioned that this might be an issue with safety critical systems, such
as the ATC system or aircraft systems.  We then did a quick mental check
of potentially affected systems.

To our knowledge, the ATC system shouldn't be impacted for a couple of
reasons (ironically, they cover both extremes)

1) The existing, older ATC computers are so old that they don't have
internal date encoding that includes the year; they were developed with
only day-of-the-month encoding to reduce the amount of unneeded
information occupying memory.  The ATC system basically "re-invents"
itself every day anyways; nothing is really stored longer than is
necessary (i.e. more than a few days to make sure that there isn't an
incident after the fact which may need some replaying of data.)

(Actually, to clear up a fallacy, those ATC systems which deal with
Flight Plans - like the Center Host Computer System - are late 70's
vintage (solid state) computers, and do not typically have vacuum
tubes.  Some very old, unique equipment at some facilities may have
vacuum tubes, but for the most part, the current ATC system is

2) The newer ATC computers which are under acquisition are actually new
enough to have no problem with the Y2K problem.  (Some of them, I
believe, are current Sun products.)

Similarly, aircraft avionics do not require the year to function - at
most they need the day of the month to work properly.  The only aircraft
system which *might* need the year to function would be Flight
Management System Navigation Databases, and this is mainly to ensure
that the nav data used is the current data.

However, from a recordkeeping and support standpoint, it is possible
that airlines might need to upgrade their *ground* recordkeeping systems
to avoid Y2K issues.  These include maintenance scheduling systems,
component status history data bases, reservations data bases, etc.
However, these are not systems which are "flight critical" as that term
is normally understood.

The above analysis is not exhaustive, but I think is a reasonably fair
estimate of the situation.