Wave Vortex Avoidance

From:         Peter Ladkin <ladkin@TechFak.Uni-Bielefeld.DE>
Date:         23 Aug 96 13:45:07 
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Things are getting a little better in Cyberspace. I just read an article in
the International Herald Tribune:

[begin quoted article]

U.S. Orders Planes to Stay Farther Behind Jumbos

WASHINGTON (WP) - The Federal Aviation Administration has ordered dozens of
smaller regional and business aircraft to fly greater distances behind
jumbo jets when landing to avoid air disturbances that flow from the wings
of the large planes.
  The new rules might cause delays at some airports.
  In addition  to a 6-mile(9.6-kilometer) mandatory separation between
smaller aircraft and the biggest jets, such as the Boeing 747, these aircraft
must also maintain a 5-mile separation between themselves and the Boeing 757.

[end quoted article]

I thought that this couldn't be saying quite what was going on,
because I believe the Air Traffic Controller's Handbook talks about
separation between Heavy, Large and Small aircraft, not between types,
and furthermore there's no `requirement' in the FAR, or even advice in
the AIM, for separation that discriminates aircraft by type.

So I looked at the FAA WWW site, and in 5 minutes of surfing, found
FSAT 96-12/FSGA 96-07, which redefines the classification of aircraft
into Heavy/Large/Small. New is H: \geq 255000lbs; L: \geq 41000lbs &
< 255000lbs; S: <41000lbs. "This action moves 55 aircraft into the
small category that were previously classified as large. [...] THe SF-340
and ATR-42 will be exempt from the small category and will be classified
as large aircraft for separation purposes. On-going studies may exempt
other aircraft in the future."

I'm pleased that I can now get accurate information on newsworthy
topics direct from the (pardon me, fellas) horse's mouth. But I continue
to regret that the news services feel the need to rework the FAA's notice
to make it (in my view) more imprecise before distributing it. It's a
trivial exercise to rework the news story above to reflect the contents
of the FSAT accurately, without using up more column space.

Peter.