What is the first action a pilot must take after deviating from a flight rule?

The first action a pilot must take after deviating from a flight rule is to notify Air Traffic Control (ATC) as soon as possible. This is critical for maintaining safety and ensuring that all parties are aware of the situation. Informing ATC allows them to assist the pilot in reestablishing normal flight operations and managing the airspace accordingly. Quick communication with ATC is essential because it helps maintain situational awareness and can prevent potential conflicts with other aircraft.

While other actions, such as filing a report with the FAA or contacting the airline's operations center, are important, they typically occur after immediate safety concerns have been addressed. Documenting the incident in a personal log also serves an important purpose for the pilot's records but is not the immediate priority once a deviation has occurred. Thus, notifying ATC stands out as the most crucial first step in the event of a deviation.