What is the first of the four parachuting time warnings?

The first of the four parachuting time warnings is indeed 20 minutes. This time warning serves as an important organizational cue for jumpers and support personnel, allowing them to begin their final preparations for the jump.

At 20 minutes, personnel ensure that all necessary gear is ready and that jumpers are gathered for a briefing. This warning helps maintain an efficient timeline and ensures that everyone is aware of the upcoming events and adjusts their pace accordingly.

Subsequent warnings occur at shorter intervals, designed to focus attention as the jump time approaches. Each warning plays a vital role in the overall safety and success of the parachuting operation, but the 20-minute mark is crucial as it initiates the final countdown phase.