[LEAPSECS] Leap seconds have a larger context than POSIX

[Steve Allen]

On Sun 2020-02-02T17:59:20+0000 Michael Deckers hath writ:
> The maximum deviation |UTC - UT1| <= 0.9 s as stipulated in
> 1974 by CCIR Rec. 460-1 has never been violated until now.

That violates the agreement that the difference between
UTC and UT1 would be encoded as part of the time broadcasts.

> > In one case it was broken specifically because a high official at CCIR
> > conceded to a high official from USSR and directed the BIH to violate
> > the wording of the existing agreement.
>
> Do you mean the only violation of applicable CCIR rules, the
> introduction of a leap second into UTC at 1973-01-01?

Right.  Sadler covers this in his memoir and in several contemporary
publications.

Delving into this reveals more of the fear in the process.

Several memoirs show that the principals involved with the creation of
UTC with leaps were very concerned that the change of broadcast time
signals might cause havoc with ships using celestial navigation.
Reading through those shows palpable relief when they managed to evoke
from the Maritime Safety Committee of the IMCO a statement that Rec.
460 would not cause difficulties with navigation predicated on the
expectation that governments whose radio broadcasts used new UTC would
issue notices about the change of their broadcasts.  That meant that
the Time Lords did not have their arses on the line if a ships might
collide as a result of the new system.  With the maximum difference of
0.7 s that could be encoded in the radio broadcasts not being able to
handle the 0.9 s difference that put their arses back on the line.

Other concern was expressed that exceeding the 0.7 limit might be
blamed on the BIH and might trigger governmental review of the
operation and funding of the BIH.  At that time about 80% of the funds
for BIH were coming from Observatoire de Paris as slush from their
allotment from the French government.  That was hardly an
"international" arrangement, but BIH had only just been handed the
responsibility for maintaining TAI specifically because any other
arrangement would have required effectively duplicating the
expertise and hardware of the BIH and finding a way to fund that.

Prompting governments or journalists to open an investigation into the
process of writing an international "technical" specification that was
violated in less than two years was not a welcome notion.

--
Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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