When an air tanker makes a long, extended retardant drop, it is called a __________ drop.

An air tanker that makes a long, extended retardant drop is referred to as a trail drop. This term describes the technique in which the tanker releases its fire retardant along a continuous path over a designated area, rather than in short bursts or targeted spots. The purpose of a trail drop is to create a linear barrier that can help slow or halt the spread of fire, particularly in areas that require effective containment lines.

Using a trail drop allows for a more effective application of the retardant, providing a consistent and thick application that is crucial in suppressing fire spread over large distances. This method contrasts with other techniques that may involve shorter, more concentrated applications but do not cover extensive areas in a single pass. Thus, the choice of "trail drop" accurately reflects the operational strategy used in aerial firefighting to manage wildfire behavior.