ATC Clearances and Readback
Core concepts
An ATC clearance is an authorisation to proceed under specified conditions. It does not relieve the pilot of responsibility for terrain clearance, wake turbulence separation, or compliance with regulations. Understand clearance limits, level restrictions, speed control, and the readback requirement for safety-related items.
Traps in questions
The classic trap is assuming a clearance authorises descent below the minimum safe altitude - it does not, unless the aircraft is under radar control and the clearance explicitly permits it. Another trap is a clearance limit: if you reach the limit without further clearance, hold and advise ATC. Speed restrictions on approach must be read back and complied with unless cancelled. Also know that a heading instruction is not a track instruction.
Worked example
Cleared "descend to 4000 ft, speed 180 kt until 5 DME, then resume normal speed". Readback must include both the level and the speed restriction with its termination point. If the aircraft cannot comply with 180 kt, advise ATC immediately rather than accepting and deviating.
Rule of thumb
Read back everything that changes your flight path, level, speed or frequency, and query anything that conflicts with terrain or performance.
Clearance limit discipline
If no onward clearance is received by the limit, enter the holding pattern, reduce speed as required, and inform ATC.