This is a very informative discussion. Regarding using PAN and MAYDAY in the U.S., I believe we are a little more pragmatic, and "DECLARING AN EMERGENCY" is used more than MAYDAY. In 37 years of flying in the U.S. I have never heard PAN used, though it was mentioned in ground school for my private license.
I had to declare an emergency departing RAF Akrotiri about two years ago, and directed my FO to "declare an emergency," which he did, in those words. The very talented and professional RAF controller understood those words without a hitch- bless him!
Check 6
