And changing tasks in the air is insanity.

Peter:

All over Europe, I hear this opinion. "unsafe!"" "heavens, they'll
run in to each other programming pdas" And so, off in to the
thunderstorm we go, just because that's the task someone picked at 9
am

You and the rest of the gliding world discussing rules would do a lot
better if we were all to listen to experience rather than just
theorizing.

The US has been changing task in the air for over 25 years -- since
long before flight computers. It's done carefully and methodically --
we're not stupid you know. Usually there is a task B, so all that is
done is "now that we see where the storm is on the radar loop, we're
changing to task B" Very rarely a whole task will be entered. We give
at least 10 minutes and more often 15 for task entry time, pushing
back the start. We brief pilots over and over again how to do this.
Wait a few minutes -- don't all do it at once. Leave the start gaggle.
Look around. Then reprogram. We do a roll call on the radio, does
everyone have the task and has had a chance to reprogram. Only then do
we go.

Now, off theory and on to experience. Not once in 25 years has there
been an accident, incident, or even a near miss caused by
reprogramming computers in response to a task change. NOT ONCE. So
much for theory. We've had crashes in every other imaginable way, and
a few creative ones besides.

This is helped by the US start procedure, which the rest of the world
also hooted down at Uvalde based on theory, ignoring 25 years of
experience. We limit altitude at the start, and require you stay 2
minutes under the start height. "Heavens, they'll just look at the
altimeter and run in to each other" screams theory. No, 25 years of
experience says NOT ONE incident of the sort. What we save are the
gaggling in the starts, big start gaggles going off into the clouds
together, VNE dives through limited-altitude starts that don't have
time limits, and sticking with the gaggle for half an hour to gain
the last 50 feet that everyone else seems to love. (With a limited
altitude start, you can go away, reprogram, and know you'll easily get
back to start altitude in a short time; you don't have to stick with
the gaggle like glue.)

No not perfect. But we haven't stuck with this for 25 years because
we're insane.

Experience is actually a pretty good teacher, if we will only listen
to her.

John Cochrane