"SeeAndAvoid" wrote in
link.net:

Cruise Clearances: the reason it's not used much and rarely offered,
here anyway, is terrain and radio/radar coverage. It's basically
a block altitude from whatever you give away, to the ground, and
if it doesn't work out, back up to whatever altitude you assign.
That's one hell of a chunk of airspace to lock up. And you are never
sure how long you are really giving it away for as you may not hear
the aircraft cancel. Also things not used often or on a regular
basis, controllers get rusty on, let's be honest.

Anyone gets rusty on things they don't do. The ZHU controllers tend to
stay up on cruise clearances because they issue them all the time. It's
the only way things can get done out in the Gulf, because of lack of radar
and radio coverage. We go out IFR and fly instrument approaches to
offshore platforms, and our letters of agreement with ZHU say that we
'shall' request a cruise clearance when within 40NM of our destination.
(Whoever wrote that LOA didn't know the legal meaning of 'shall',
obviously, since it's used many times when the context makes it obvious it
should be 'will' or 'should'). It does tie up lots of airspace, but there
is just no other way of doing it, with the current equipment situation.
Everyone tries to cooperate by cancelling as soon as possible, and we all
have company comm centers which can call center for us and cancel when we
lose comm with ATC. I've never received a cruise clearance inbound,
though.

--
Regards,

Stan