What must number 1 communicate to number 2 when approaching the final approach segment?

When number 1 communicates to number 2 during the final approach segment, it is critical to inform them about the expected go-around procedure. This communication is vital for maintaining situational awareness and ensuring that both aircraft are prepared for any potential changes in the landing scenario.

In formation flying, effective communication of the go-around procedure allows number 2 to anticipate the actions that number 1 will take should a go-around become necessary. This includes understanding the reasons for the go-around, the flight path, and what both pilots should do afterward to maintain safety and formation integrity.

The other options, while important in different contexts, do not pertain specifically to the dynamics of formation flying during the final approach. For example, landing gear status and runway clearance are typically confirmed as part of pre-landing checks and may not need to be reiterated unless there's a significant change. Altitude and heading are also important but more relevant during cruising or initial approach rather than during the specific phase of the final approach segment. Therefore, the emphasis on go-around procedures is what sets number 1's communication apart during this critical phase of flight.