Probably a dumb question, but...
Hi,. .Hope someone can help - it should be an easy one for you!. .On a recent flight with United I spent most of the time listening to the ATC channel - fascinating stuff, even though I was convinced I was going to hear my pilot making a mayday call!. .Most of it was easy enough to understand, but the meanings of 2 words eluded me - 'squawk' and 'heavy' (as in "United 123 Heavy"). .Please can someone explain these in context?
Thanks lots!