Graeme Cant wrote:
Paul Remde wrote:

I must respectfully disagree. If we just use sunset as the end of soaring
flight that gives an unfair advantage to a pilot that is far from home or at
altitude when the sun sets. He/she should have planned ahead and landed on
time.

And exactly which time would that be, Paul?

The time calculated by the USNO, the "the preeminent authority in the
areas of Precise Time and Astrometry" (at least in the US).

You seem to have lost track of the story so far:
Doug wants to be able to pick illegal flights on OLC but he's having
trouble deciding which flights are illegal because he doesn't know when
it's "sunset" (as 'un'defined in the FARs) at all the places OLC flights
go to.

First, how dare you decide what I "want" based on what? If you look at
the subject line, and the original post to this thread, a reasonable
person would conclude that I do not want to do as you insinuate, and am
trying to warn pilots in advance, so it does not become a bigger issue.


Now read on:

I know this won't help but in Oz the rules a
1. "Night" is the period between the end of evening civil twilight and
the beginning of morning civil twilight.
2. CASA (FAA equivalent) publishes beginning and end of daylight graphs
for latitudes from 0 to 45 throughout the year.
3. Daylight flight occurs between those times after converting local
time to Standard/Daylight Time.

Note that daylight "ceases" at a particular longitude solely dependent
on its latitude. No allowance for terrain, etc.

And the date of course. This is based on the zenith angle of the sun.

But the following is also in the AIP:
"Users ... should note that the parameters used in compiling the ...
Graphs do not include the nature of the terrain ... other than a
cloudless sky and unlimited visibility ... Consequently, the presence
of cloud cover, poor visibility or high terrain to the west of an
aerodrome will cause daylight to end ... earlier than that extracted
from the appropriate graph.
Allowance should made for these factors when planning a flight..."

Yes, and all of these factors make sunset earlier, not later than
predicted by the standard formula for almost all normal soaring
flights. Unless you are flying off of a west facing beach in Winter,
sunset will be earlier than predicted because the horizon will be
higher, and the refraction will be less because the atmosphere is less
dense than standard sea level.

The rules are reasonable but are no help in maintaining a level playing
field for a gliding competition.

So, Doug. Make up your mind what arbitrary rule you would like to
implement for the SSA-OLC and publish it. Let's say - evening civil
twilight at the latitude.

This is similarly an insulting insinuation. First off, I am not making
the rules, just trying to follow the direction the Committee and I have
been given by the Board. The direction is clear; the flight must end by
sunset, unless approved lighting was used, and this is noted in the
comments section of the OLC claim.

Stop using the FAA as an excuse and a crutch. Stand on your own feet.
Make a rule. Publish it. Enforce it. Cop the flak.

Done. Done. and being Done.