For many years, the USA had by far the largest air travel market in the
world, and so could call all the shots. That is no longer true. The rest of
the world could bring together the following factors, if it so chose, to
effect a change in the not too distant future:
1. The air travel market outside the US today easily eclipses that of the
US, and is still expanding, whereas the USA is a relatively mature market,
with little further expansion possible (and maybe even is contracting).
2. The old USSR (and maybe the CIS today?) used metres for altitude and km
for horizontal separation and speeds, which must have given pilots of
western aircraft something to think about when flying into Moscow, so there
is some experience there in using metric units in the aviation business.
3. As Michael Payne said, modern aircraft (and outside of the US that is
most of the world's aircraft, made in the last 30 years) have electronic
displays which are (or easily could be) switched to metric units.
4. When I lived in Canada, I once on a transcontinental flight sat next to
an air traffic controller, who said there were plans, of which Canada was a
lead nation, to convert to metric units. That was 25 years ago. But it shows
there was a will even back then.
So why don't the metric nations of the world unite and force the change?
Technically it is quite easy. The USA would find it most difficult, as many
US airlines have quite elderly fleets - but that is changing, Delta have
announced a fleet renewal program, and American have just ordered 350
aircraft (100 737s and 250 A320s).
There is also the military to think about - I remember reading around 20
years ago after the break-up of the USSR that many Soviet military aircraft
in the satellite nations were being co-opted into NATO fleets - and having
to have all their instrumentation converted to imperial units, which was
retrograde step if ever there was one. As the military around the world uses
metric units everywhere else, surely there would be an incentive here.
Perhaps there is not the will today to change around the world, even in
otherwise totally metric countries? There would be a cost of course, but
surely there would be a benefit. Michael Payne mentioned the possibility of
reduced altitude separations. They used to be 2000 feet, and at one time I
thought it would be good to be able to reduce them to 500 m. But I believe
they have recently been reduced to 1000 feet, so that argument unfortunately
falls away.
But personnel in metric countries would surely not have to learn an alien
measuring system, so there would be a benefit there.
It is a big thing to change, but there is surely today enough power and
influence outside of the USA to make the change happen.
John F-L
----- Original Message -----
From: "Michael GLASS" <m.gl...@optusnet.com.au>
To: "U.S. Metric Association" <usma@colostate.edu>
Sent: Monday, July 25, 2011 1:43 PM
Subject: [USMA:50915] Metrication of air travel
Dear USMA,
I wrote to our civil aviation safety authority as follows:
I note that the safety rules are drawn up in feet while all Australian
maps
are now in metres. This is obviously a safety issue because the training
manual for hot air ballooning warns, "Watch out – aviation charts
and
your altimeter are calibrated in feet, but topographical maps usually show
contours and spot heights in metres!"
"ABF Pilot Training Manual, Part 8, Navigation, Version 1 - May 2006"
Could CASA push for the metrication of all the measures? I am sure that it
would be safer for all if all the measures were metric.
Yours sincerely,
Michael Glass
This is their reply:
Dear Mr Glass
On behalf of the Director of Aviation Safety, thank you for your email.
The common international standard for altitude measurement in aviation is
feet and this is why Australian aeronautical charts use feet as the
measurement of altitude. Where topographical maps are used in aviation
activities that you must be careful to remember they are showing altitude
in
metres and to take care when converting data. There is no current plan to
change the aviation measurement of altitude from feet to metres and it is
likely Australia would only move in this direction if there was an
international change.
Regards
Peter Gibson
Manager Corporate Communications
Civil Aviation Safety Authority
0419 296 446
Over to you, USMA. How about pushing for a change with your civil aviation
authorities?
Best wishes,
Michael Glass
