Question

You are inbound to the Peachtree Dekalb airport (KPDK) and have been assigned the DIFFI THREE ARRIVAL STAR. After passing the TEMPO waypoint, ATC assigns you a heading of 090 and descends you to 4,000 feet. Does this mean your clearance for the DIFFI THREE ARRIVAL has been cancelled?

1) Only if the controller tells you it has been cancelled.
2) Once cleared for a SID or STAR, the clearance remains valid until you are handed over to tower.
3) Yes, when ATC gives you instructions which deviate laterally from the SID, it's implied the SID is cancelled.
4) No, those instructions are only valid after DIFFI.

Answer 1

Being assigned a new heading and altitude by ATC does not cancel a previously assigned STAR unless explicitly stated by ATC.

Step-by-step explanation:

When assigned the DIFFI THREE ARRIVAL Standard Terminal Arrival Route (STAR) and you have been given a heading of 090 and descent to 4,000 feet after passing the TEMPO waypoint, it does not necessarily mean your clearance for the STAR has been cancelled. The correct answer is 1) Only if the controller tells you it has been cancelled. In aviation, ATC clearances for STARs and SIDs remain in effect unless explicitly cancelled or amended by ATC. A new heading or altitude assignment might be for traffic separation or sequencing and does not imply the cancellation of the STAR unless specifically stated.

When ATC assigns you a heading and descent altitude after passing the TEMPO waypoint, it does not automatically cancel your clearance for the DIFFI THREE ARRIVAL STAR. The instructions given by ATC are meant for vectoring purposes and do not cancel your pre-assigned clearance. Your clearance for the DIFFI THREE ARRIVAL STAR remains valid until you are handed over to the tower.