During an instrument trail departure, what code will number 2 squawk?

In an instrument trail departure, the code that the second aircraft (number 2) will squawk is 0100. This is a specific transponder code assigned to aircraft participating in a formation flight or when operating under instrument flight rules (IFR) in a specific departure scenario.

This code essentially indicates to air traffic control that the aircraft is part of an organized and identified group, allowing for better tracking and management of air traffic. When number 2 squawks 0100, it provides a clear and distinct signal that helps controllers distinguish between different aircraft operating in proximity to each other in a controlled environment, improving safety and coordination during takeoff and initial climb-out.

In contrast, other codes have different meanings: 1200 is the code for VFR flight; 7500 indicates a hijacking, and 4000 does not typically relate to this specific procedure. Thus, squawking 0100 in an instrument trail departure is aligned with standard protocols in air traffic management for this scenario.