"What part of an ATC instruction must I read back? Some people just read back a bit of the instruction and use short callsigns. Others readback every word exactly as it was said. What's best?" — Greg R.
“You should read back pertinent information and instructions containing altitude assignments, vectors, runway assignments, etc. The readback of the numbers serves as a double-check between pilots and controllers and reduces the kinds of communications errors that occur when a number is either misheard or is incorrect.
Read back the numbers in the same sequence as they are given in the clearance or instruction.
Include the aircraft identification in all readbacks and acknowledgments. This helps controllers to determine that the correct aircraft received the clearance or instruction. The requirement to include aircraft identification in all readbacks and acknowledgments becomes more important as frequency congestion increases, and when aircraft with similar call signs are on the same frequency.
Initial readback of a taxi, departure, or landing clearance should include the runway assignment, including left, right, center if applicable.
The same with frequency changes or transponder codes: Read back the numbers but keep it short and simple. For example, if the controller instructs you to contact the tower on a certain frequency, you do not need to read back the words ‘Contact the tower,’ simply say, ‘Tower 120.3, Cessna Five One Eight.’
Always use your call sign to end the transmission.”
Will you shorten your callsign when replying to ATC even if the controller hasn't shortened it first?