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Using feet not meters for altitude?

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Using feet not meters for altitude?

Old 28th May 2010, 12:59
  #21 (permalink)  
 
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IIRC, NASA lost an unmanned mission owing to a mix-up between metric and imperial units. In September 1999, its $125 million Mars Climate Orbiter probe was destroyed because its attitude-control system used Imperial units, but its navigation software used Metric units. As a result, it was 100 kilometres too close to Mars when it tried to enter orbit around the planet.

The interesting thing is that Uncle Sam has decreed (in a 1988 Act of Legislation), that all U.S. Govt Depts, including NASA, go all-metric.
The Inspector General has been hassling and pressuring all Depts to implement this change, under the enacted legislation.

Unfortunately, NASA, like so many other Depts, Entities, & Divisions... can't swap over to metrics overnight. Virtually everything they currently have, and operate with, is rooted in Imperial measure design. The 30 year old Space Shuttle design, is all-imperial measurements.

NASA have estinated the cost to convert fully to SI measurements is around $370M - almost half the cost of a Shuttle launch. Then, there's still the hangover of all the items that were built in Imperial sizes, that will still be around for a while yet. The unspoken thing is, that conversion to a full SI system, still isn't going to eliminate another possible disaster due to measurement system confusion.
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Old 29th May 2010, 17:27
  #22 (permalink)  
 
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The unspoken thing is, that conversion to a full SI system, still isn't going to eliminate another possible disaster due to measurement system confusion
Exactly...therefore, don't change anything and save the funding for other things.....or....not spend at all.

Simples.
America is big enough, that actually, we don't care what the rest do.
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Old 30th May 2010, 12:25
  #23 (permalink)  
 
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Just wondering, if an airline is flying to Russia or China, is there any provision for the altitude in the FMC or FMGC to be converted ? I know there is MTR button in the 777, not sure of Airbus though.
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Old 31st May 2010, 20:31
  #24 (permalink)  
 
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Feet are used for vertical separation (including terrain & obstacles) and metres for horizontal separation (including viz) so as not to add further confusion.
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Old 31st May 2010, 21:14
  #25 (permalink)  
 
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...and metres for horizontal separation
Ahhh, sorry, no.
Many countries (most actually) use nautical miles for horizontal separation.
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Old 1st Jun 2010, 03:02
  #26 (permalink)  
 
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-Feet for altitude/vertical separation, and in some countries, RWY length.
-Metres for RWY length in other countries, and horizontal visibility.
-Km for horizontal visibility when the viz is greater than 5 or 8 KM, depending on the application (Metar/Atis)
-Nautical miles for horizontal separation.
-Operating systems (in my tower) based on both Windows and Unix. Configured to both work differently.
-For pilots, US fuel gauges in US gallons, dipstick in litres or gallons (IMP or US), consumption figures can be in US or IMP gallons, pounds, kilograms or litres. Typically when I was flying quite a bit in the 80's, the bowser was in litres, the dipstick in IMP gallons, the gauges in US gallons, weights were in either pounds or kilograms....I became pretty proficient at quick mental conversions, and an ace on the E6B.

Not confusing at all. No problem.
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Old 1st Jun 2010, 22:19
  #27 (permalink)  
 
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Flight Detent wrote:
Wasn't feet used because it's a part of a statute mile, and the earth's circumference is approximately 24,000 statute miles, (at the equator) and, I've heard, rotates once each 24 hour period, which conveniently aligns with my watch!

That's it then...

Cheers...FD...
So, you own the watch that controls the rotation of the earth! I was wondering who had it.

Please keep an extra battery handy.
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Old 12th Feb 2019, 14:40
  #28 (permalink)  
 
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So I was right then
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Old 12th Feb 2019, 15:48
  #29 (permalink)  
 
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Originally Posted by Itellbiglies View Post
So I was right then
Not quite, and realising that after 9 years is really a very slow reaction time.
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Old 12th Feb 2019, 16:04
  #30 (permalink)  

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I use feet because that's what is written on my altifeeter.
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Old 13th Feb 2019, 01:59
  #31 (permalink)  
 
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So what is stopping me flying in meters? What about the ATC side of things is there something that says they must operate in feet?
What a ridiculous question. Sounds like something imagined over one too many a glass of red. In no world does flying in meters when everyone in the airspace around you is flying in feet make any sense..... not even remotely!

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Old 13th Feb 2019, 12:32
  #32 (permalink)  
 
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Originally Posted by Atlas Shrugged View Post
What a ridiculous question. Sounds like something imagined over one too many a glass of red. In no world does flying in meters when everyone in the airspace around you is flying in feet make any sense..... not even remotely!

Funny thing is, i learned flying in meters, speed in km/h. In an airspace that follows the european standard (altitude in feed, speed in knots, visibility in km, runway length in meters etc). And i know there are over 30.000 pilots in this country alone doing that. Glider pilots in germany...
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Old 15th Feb 2019, 13:40
  #33 (permalink)  
 
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It makes good sense using different units for different functions (altitide in feet, speed in knots, visibility in metres, etc) to avoid confusion. Similarly why do you climb and descend? Because you are less likely to confuse climb rather than ascend with descend.

On a separate issue, its just as well that tons aren't used (long, or short, a 12% difference).

Incidently do US airlines still use US gallons? They can be confused with imperial gals. Luckily I am not aware of imperial gallons being used anywhere.

Last edited by Peter47; 23rd Feb 2019 at 15:08.
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Old 15th Feb 2019, 19:12
  #34 (permalink)  
 
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The OP said that s/he had looked at Annex 5 - and the answer is in there (and it hasn't changed much since the original post).

In simple terms, in the early days of aviation, different States used whatever units of measurement were commonly in use or made sense at the time.- what else would you expect to happen? Since then, aviation has become a global industry and ICAO was established, amongst other things, to set International Standards to facilitate international aviation wherever the aircraft may come from and wherever it may be flying. ICAO is seeking to move toward SI units, which coincidentally have been adopted by the International Standards Organization. But the date to harmonise on SI is not specified because agreement cannot be reached by all States on when to do it. In the meantime, each State decides when it will use non-SI units for those parameters which are permitted to be specified in non-SI units within their own airspace and promulgates this information in their AIP. reportyourlevel gave you the reference for the relevant pages of the UK AIP.

Lecture over.....what do they teach youngsters these days????
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Old 16th Feb 2019, 13:53
  #35 (permalink)  
 
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Originally Posted by LookingForAJob View Post
Lecture over.....what do they teach youngsters these days????

Apparently not the difference between metre and meter.


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Old 17th Feb 2019, 13:58
  #36 (permalink)  
 
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When I started my apprenticeship in 1969, I was told by a college lecturer that we were going metric in 1971, but unfortunately we had to learn Imperial measure for the first two years, after that we would never use it again.
Last night I distinctly remember using a 7/16 inch socket on a 1/4 inch ratchet !!!!
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Old 17th Feb 2019, 13:58
  #37 (permalink)  
 
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Originally Posted by jimjim1 View Post
Apparently not the difference between metre and meter.

Well, aviation has yet to learn the far more significant difference between alternative (n) and alternate (v) - and steadfastly uses the wrong one!
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Old 17th Feb 2019, 22:17
  #38 (permalink)  
 
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Originally Posted by dixi188 View Post
using a 7/16 inch socket on a 1/4 inch ratchet !!!!
You could have used an 11mm one if you prefer to stay half metric wise.

Thank god the drive side hasn't changed.

One of the few small ones that are close enough for most purposes. I seem to recall that it works either way round.

= 11.125mm or if you prefer 11 1/8 mm

I have not checked but I seem to recall that 5/16 is v close to 8mm
Then you don't get a decent hit until 19mm and 3/4 which are also interchangeable.

I don't recommend this for work on Aircraft but it's OK for plumbing.
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Old 17th Feb 2019, 22:32
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Originally Posted by meleagertoo View Post
Well, aviation has yet to learn the far more significant difference between alternative (n) and alternate (v) - and steadfastly uses the wrong one!
You probably noticed this -

Alternate is
"another term for alternative.
"a novel set in an alternate universe"" (thanks google)

in North America.

That one is going to spread in the aviation trade!

Out of interest are Boeing (others?) Manuals localised to UK English or are they available only in American English?
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Old 18th Feb 2019, 12:12
  #40 (permalink)  
 
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And another thing:

Why in Britain do we buy our car fuel in litres but measure fuel consumption in miles per gallon.
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