From kls Wed Apr  9 03:09:28 1997
Newsgroups: sci.aeronautics.airliners
Path: bounce-back
Date: 09 Apr 97 03:09:28 
From: "Mark E. Ingram" <markt@mickey.mo-net.com>
Subject: Re: 42,000 feet
Message-ID: <airliners.1997.911@ohare.Chicago.COM>
Approved: kls@ohare.Chicago.COM
Sender: kls@ohare.Chicago.COM
Reply-To: "Mark E. Ingram" <markt@mickey.mo-net.com>

On 30 Mar 1997, BHunnewell wrote:

> I've always been told that the big advantage to flying higher in jets
> is that the engines get more efficient as it gets colder. Above the
> tropopause-the air continues to get thinner but the temp remains
> constant, so, there is no real increased efficiency to flying above the
> tropopause.

I think you are correct as to efficiency, but there are times that I have
climbed to FL 450 (45,000') to top weather.  An aircraft's capability to
go there - and above - can *really* be handy in such situations.

Regards,

Mark E. Ingram

MarkT@Mo-Net.Com (also mingram@mail.orion.org)