What must a pilot do if they need to deviate from an ATC clearance?

When a pilot needs to deviate from an Air Traffic Control (ATC) clearance, it is essential to request an amended clearance. This action ensures that the pilot maintains communication with ATC, allowing them to provide updated instructions that account for the change in flight path. It is a safety protocol designed to prevent conflicts with other aircraft and ensure that air traffic is managed effectively.

Requesting an amended clearance is necessary to maintain situational awareness for both the pilot and ATC. This helps in coordinating the aircraft's new route or altitude with other air traffic in the area. Being transparent about deviations reinforces the importance of clear communication in aviation, which is vital for maintaining safety in the airspace.

Continuing to fly as planned or changing course without clearance could lead to dangerous situations, including potential collisions or airspace violations. Returning to a previous waypoint is not typically a prescribed action unless explicitly instructed by ATC. Thus, seeking an amended clearance is the correct and responsible choice.