Which of the following describes "loss of separation"?

The concept of "loss of separation" pertains specifically to aviation safety and refers to a situation affecting the proximity of aircraft in the same airspace. This can occur when two or more aircraft get closer to each other than is deemed safe, whether in terms of vertical or horizontal distance. Maintaining proper separation is critical to avoid mid-air collisions and ensure safe operations.

In air traffic control, specific minimum separation distances are mandated to ensure safety between arriving and departing aircraft. When these distances are violated, it results in a loss of separation. This frequently involves monitoring air traffic patterns, managing altitude, and ensuring that air routes are clear to maintain safety for all aircraft involved.

The other options, while relevant to different aspects of aviation, do not accurately describe the term "loss of separation." Communication failures between pilots, maintenance issues, and passenger delays pertain to operational challenges but do not reflect the specific situation where safety in airborne distance is compromised.