Which equipment must a pilot wear when performing spins, except for training purposes?

When performing spins outside of training purposes, a pilot is required to wear a parachute for safety reasons. Spins are inherently risky maneuvers that can lead to an uncontrolled descent, and having a parachute provides a significant safety measure, allowing the pilot to exit the aircraft in an emergency situation. This requirement is in place to mitigate the dangers associated with spins, which are complex and can lead to loss of control if not executed properly or if the aircraft is not equipped for such maneuvers.

The other equipment listed, such as a headset, flotation device, and safety harness, may play important roles in flight safety and comfort but do not specifically address the heightened risks involved with executing spins outside a training environment. The parachute is specifically mandated because it enhances the pilot's ability to safely escape in the event of an emergency arising from a spin maneuver.