How is heading crossing angle (HCA) defined?

Heading crossing angle (HCA) is defined as the angular difference between the longitudinal axes of two aircraft. This concept is crucial in formation flying as it helps pilots understand how their aircraft are oriented relative to one another. When two aircraft have different headings, the HCA indicates the angle that exists between their respective flight paths, which can be critical for maintaining safe separation and effective communication during complex maneuvers.

Understanding HCA is essential for coordination in formation flight, as it directly impacts tactical decisions like turns, spacing, and potential crossovers between aircraft. By being aware of the angular relationship between the aircraft, pilots can make informed decisions to maintain formation integrity and avoid potential conflicts.