In misc.metric-system Markus Kuhn wrote:
If flight levels were named in meters and were all a multiple
of 300 m, this might even add an additional communications-safety
mechanism:

In all valid flight levels, the sum of all digits would
always be divisible by three.

This adds a bit of healthy redundancy to a figure that needs
to be communicated without ambiguity over noisy radio channels.
Getting a single digit wrong would be spotted with 60%
probability. Almost as good as adding a check digit.

Subsequently I would like to have a similarly clever idea
how to define SemiCircular Flight Level Rules.
Unfortunately I did not succeed to ignite a contest of ideas
in www.avweb.com via the QuestionOfTheWeek (qotw).
Obviously, U.S.Americans resist international needs.

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--Peter Hermann(49)0711-685-3611 fax3758
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