On Mon, 03 Apr 2017 19:01:59 +0000, alister wrote:

> interesting as a SCUBA diver I use metric (Meters & Bar) because it
> makes the maths easier & at 30M+ the brain is not working too well :-)
>
Yes, we have the same problem, but from going the other way. However,
there are two mitigations:

- for starters, the variometer used to be a simple rate of climb
indicator driven off a total energy compensated pressure probe. Now, with
the addition of feeds from static pressure ports, pitot tube and a GPS,
it shows us where we are on a moving map display relative to terrain and
the task we've declared, predicts arrival height at the next turnpoint,
and calculates windspeed and direction. IOW, it does almost all the
calculations we used to do in our heads or with a whizz wheel calculator
back in the day when a map was a large sheet of glossy paper with the
task of the day drawn on it.

- Flying rules say that using oxygen is advisable above 10,000 ft AMSL
and mandatory above 12,000, though in the US you're allowed up to 13,400
ft without oxygen provided you're not above 10,000 for more than 30
minutes.


--
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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