What color does the red beacon light turn to when the aircraft senses weight off wheels?

When the aircraft senses weight off wheels, the red beacon light turns to a white strobe. This change in light color serves as an indicator that the aircraft is airborne and confirms that the landing gear has retracted after takeoff. The white strobe acts as a visual cue to both the flight crew and those monitoring the aircraft’s status that it is in a phase of flight where it is no longer in contact with the runway.

This function is critical for maintaining awareness of the aircraft's operational state during takeoff and ensures that all systems are functioning as intended as the aircraft transitions from ground operations to flight mode. Thus, the white strobe light is a vital safety feature during crucial phases of flight.