Re: Can't use GPS on Alaska Airlines

From:         boyd@france3.fr (Boyd Roberts)
Organization: France 3
Date:         17 Sep 96 13:53:07 
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I flew with American Airlines from Paris to New York and back in the last
two weeks and was surprised to see that they post the flight waypoints
(or some such aproximation) on maps stuck on galley external walls,
tagged with the flight time.  When I saw this I programmed them into my
GPS and created a route.  Reading the doc I saw that they allowed some
electronic devices to be used but prohibited _VHF_ radios and thought
to myself 'hah, GPS is _UHF_'.

On the sector to New York I had no problem with the cabin crew and suprisingly
no problem with my Magellan 2000, which locked up after a couple of minutes.
I was suprised to see that most of the waypoints were at 'well known' points;
10 degree lon and whole or half degree lat.  I was further suprised that
the GPS indicated only small n (5-10) kilometer differences when nearing
waypoints.  However, when I was tracking 4 satelites the altitude was out by
10's of thousands of feet.

On the Paris sector I had a problem.  One of the cabin crew objected and
took my receiver to show the Captain.  She returned after a while and said
no. My guess is that she talked to someone more senior who said 'If it's not
on this list then it can't be used' because that's more or less what she
said to me.  If the Captain had seen it I think he whould have said ok or
the response whould have been 'I've asked the Captain and he says no.'.

I thought of asking someone else but decided against it because I'd
already seen how it performed on the way over.  For the benefit of
the Garmin pukes:  yes it does register the velocity at 400-500 knots.

While in Manhattan I was a bit suprised during 31 August and 1
September when I was getting ~5 km position errors.  In the weeks
following the worst it got was 100's of metres.  Obviously Manhattan
is not great for GPS and the Empire State Building and the internal
observation deck of the World Trade Centre are a dead loss.

--
Boyd Roberts <boyd@france3.fr>                        N 31 447109 5411310

``Not only is UNIX dead, but it's starting to smell really bad.''  -- rob