Helicopter operations on the DDG51 are limited due to the fact that the present ships do not carry their own helos. The ship is able to launch, recover and fuel helos. Refueling can be a deck refueling or an inflight refueling. Masker air is used to absorb the noise created by equipment in the main engineering spaces. The air needed for the masker air system is supplied from the bleed air header to the emitter rings around the main spaces.
Prairie air is used to reduce the noise created by the ship s propellers as they turn in the water.
The air is released from the leading edges of the propeller blades. This air is also supplied by the bleed air system. Along with the use of prairie and masker air, other types of sound deadening devices are used in the engineering plant. Resilient mounts are used on all rotating equipment to prevent the transfer of equipment vibrations to the ship s hull. Flex hoses are used to connect pumps to piping systems.