Ramapriya wrote:

By the way, I also got confirmation on what I'd for long suspected to
be unnecessary - the warning to switch off mobile phones on the
aircraft. I asked how phones, which use a completely different set of
frequencies to operate in, could interfere with air traffic
communication. And the pilots did admit that it was just something
that international regulations required and that there isn't much to
evidence interference, unless satellite phones are used.

You got that backwards: Every high frequency electronic device emits
radiation and therefore can, theoretically, interfere. So the question
is not whether there is evidence that it does interfere, but whether
there is proof that it does not.

And it was only when I went looking for a gage with a ball and saw
none that I learnt (from the captain) that, "Every turn on an aircraft
is a coordinated turn". Wonder why John Denker has written a piece on
coordinated turns at all...

Certainly true for the airbus: You fly it with the joy stick, and the
computer takes care of coordination.

Stefan