In article ,
Bob Gardner wrote:
However, don't be surprised to hear a controller say "Climb and maintain one
one thousand, eleven thousand" because there have been some
readback/hearback problems with pure digits.

On Saturday I heard an airliner call in at "one one thousand, ten thousand".
He quickly corrected himself. No amount of redundancy helps if your brain
isn't in gear.

--
Ben Jackson

http://www.ben.com/