In General, in the U.S., pilots are told they
Should readback those parts of a clearance containing altitude and/or vector information. (AIM 4-4-6) Note, in the U.S. the word should does not mean *shall*.
The ATC handbook 7110.65 states that pilots may acknowledge clearances or instructions by simply saying "Wilco", "Roger", or other appropriate remarks. (FAA 7110.65, 2-4-3)
However, in another section of the .65, (3-7-2) Controllers are required to get a readback of all hold short instructions from aircraft taxiing. In addition, I recall reading somewhere, (don't recall where off the top of my head at the moment) that a controller may insist on a readback of anything he/she thinks is critical.
I don't have any problem with a professional, concise readback of everything. I don't have a problem with a simple "Roger" so long as the aircraft's ID is also clearly stated. My only "problem" is when the readback involves about twenty "Uhs" and "Lessees" etc.,
OR
Goes something like this:
fivefortytwoisclearedjaytwentyoneasfiledfourthirtyfiveninete enzeroandfiftytwofortytwo.......
Maybe a New Yorker understands all that, but us Southerners need a comma or two.....
