What survival equipment is primarily donned during the pre-ditch preparation?

During pre-ditch preparation, anti-exposure suits are primarily donned because they are designed to protect individuals from hypothermia in cold water conditions. These suits provide insulation and a barrier against the cold, which is critical in survival situations, particularly when there is a risk of immersion in water.

Anti-exposure suits also allow for greater mobility in the water, enabling the individual to swim effectively to safety or to a floatation device after a ditching event.

In contrast, floatation devices are typically put on after ditching rather than during pre-ditch preparations. Diving gear and oxygen masks are not relevant to survival during immersion or ditching, as they serve different purposes related to underwater operations or high-altitude environments. Thus, the focus on anti-exposure suits during the pre-ditch phase highlights the priority of protecting oneself against the immediate dangers of cold water exposure.