Menu Sign In Contact FAQ
Banner
Welcome to our forums

Why doesn't aviation use standard (metric) units?

Get over it

Suggested reading.

Haven’t you at least owned a scientific calculator with a DEG-GRAD-RAD slide switch?

I still have this one but the nicad battery is dead. I bought it in 1974. It has a degree – grad conversion button, though curiously no radians (must be there somewhere)

Administrator
Shoreham EGKA, United Kingdom

Maoraigh wrote:

Did British engineering still use only Imperial units at that time?

According to the documentary, yes. It suggested that every drawing and calculation was done in both systems of units, potentially catching calculation errors better than if only one system had been used.

Last Edited by huv at 03 Dec 07:19
huv
EKRK, Denmark

Feet/nm/knots/degrees won. Get over it. Any unit of measure is arbitrary.

Last Edited by JasonC at 03 Dec 00:36
EGTK Oxford

Cobalt wrote:

So does the Gradian or gon (full circle = 400 degrees) with decimal subdivisions, combined with the metre.
A kilometre on a great circle is 1/100th gon (a centigon), giving the equivalent of a nautical mile being 1/60th of a degree.
But at that time, the seas were dominated by Britain, and it never caught on.

Grad/Gon has been used by French Artillery, so I expect it to come back for runway headings in the ATIS of “FR-only airfields” most of artillery after used Anglar Mils = 1/1000 of radian, the rounding of that exact value (1/6238) depends on the countries: Nordic countries did use the most precise rounding 6300, while western compass is set to 6400 and eastern compass is set to 6000

Last Edited by Ibra at 03 Dec 00:32
Paris/Essex, France/UK, United Kingdom

Ultranomad wrote:

Haven’t you at least owned a scientific calculator with a DEG-GRAD-RAD slide switch?

I just wanted to write that

LDZA LDVA, Croatia

“The Concorde flew, and although not a commercial success I think most will agree that it was an technical marvel. That despite the fact that the two manufacturing countries used different units for everything.”
Did British engineering still use only Imperial units at that time?
Another potential danger is that US gallons and quarts are not the same as UK ones.

Maoraigh
EGPE, United Kingdom

I could be remembering this incorrectly, but was at one point were the french not also keen on metric decimal time? Fortunately that one was forgotten about.

Peter wrote:

The only “gon” I know is in “gone down the pub”

Haven’t you at least owned a scientific calculator with a DEG-GRAD-RAD slide switch?

LKBU (near Prague), Czech Republic

Mars climate orbiter too

The primary cause of this discrepancy was that one piece of ground software supplied by Lockheed Martin produced results in a United States customary unit, contrary to its Software Interface Specification (SIS), while a second system, supplied by NASA, expected those results to be in SI units

The Concorde flew, and although not a commercial success I think most will agree that it was an technical marvel. That despite the fact that the two manufacturing countries used different units for everything. So these problems can definitely be overcome.

On the other hand, there was the Gimli glider accident (pounds vs kgs of fuel-confusion), and I have also had a small number of tense moments as an instructor with pilots being used to fly in knots, now being checked out in an older aircraft of the same type, but with IAS in mph, making for slow approaces. KTs and MPH are close enough that the numbers were confused without the pilots noticing.

Last Edited by huv at 02 Dec 14:15
huv
EKRK, Denmark
139 Posts
Sign in to add your message

Back to Top