A simple, elegant watch face, designed by and for cabin crew!

As required of watches worn by cabin crew, this face has a second-hand and second-demarcations. The movement is smooth so as not to interrupt any potential counting being done for a period of time.

For fun, there's an altimeter which measures the equivalent effective cabin altitude in feet. I have now tested it, and it seems to be accurate to within a reasonable tolerance to the cockpit cabin altitude readout. An exact correlation won't be possible, because the cockpit readout is rounded off per 250 feet in the aircraft we fly, combined with an indicator to show how fast the cabin altitude is changing.

I made it for fun, mostly. If you happen to use it and like it, great!

Disclaimer: This watch face is made without any guarantee of suitability or applicability for any purpose, including the intended purpose of use by aviation professionals. It's made for fun, with hope but no guarantee of actually being useful.

Changes:

+ Per user request, a date indicator has been added

+ Altimeter readout has been moved and hand-lengths adjusted to prevent it becoming blocked by the hour hand.

Known issue:

[_]: It has been brought to my attention that the watch face should technically be able to be synchronised to the ECAM clock in the cockpit. This is not currently possible with this watch face. Your airline may or may not enforce this requirement, but please keep it in mind.

What is cabin altitude?

Air pressure drops as you climb higher. Normally air-pressure, as measured by a barometer, is read in mmHg (millimeters of mercury), inHg (inches of mercury), Atm (Atmospheres), or hPa (hecto-Pascal). Those are related directly to the force of the air on the measuring device.

A readout in terms of distance means that you're taking the equivalent height above sea-level at where you might find air at the pressure measured.

In a jet flying above the clouds, the air outside has a low pressure, so much so that extra oxygen is required. In passenger aircraft, the problem is solved by raising the pressure of the air inside the cabin to breathable levels. Keeping the cabin pressure the same as sea-level would put enormous stress on the aircraft due to the difference in pressure inside vs outside. Instead, the cabin is pressurised to a relative elevation of approximately 7500 feet, or 1/4 mile above South Lake Tahoe.

In case you happen to live at or near sea-level and notice the altimeter giving a negative reading, that's normal. The calculation uses a standard model of atmospheric pressure, which doesn't take into account the air-pressure difference created by your local weather.

The calculation used for the altitude was derived from formulas found here:

http://fisicaatmo.at.fcen.uba.ar/practicas/ISAweb.pdf