The ASQ-81 system takes a very different form in rotary wing applications. In flight, the rotorhead generates sufficient static electricity that a fixed detector is rendered impractical. Thus, first major difference comes with the detector, which is a towed body vice fixed sensor as with the S-3A/B Viking and P-3 Orion systems.
The towed body is launched from a reeling machine suspended from a pylon just to the aft and rear of the transition section of the SH-60B Seahawk. The reeling machine is also located in the same area on the SH-2F/G/H Seasprite. On the SH-3 Sea King airframe the reeling machine is mounted in the starboard (right,) sponson. A smaller version of the magnometer is used to bring the total length of the package to five feet eight inches with drag skirt and nosecone. Data is fed from the TB-408 towed body to the reeling machine via a 200 foot (180 usable feet,) copper-beryllium coaxial cable.
The reeling machine serves as the interface between the towed body and AM-4535 Magnetic Anomaly Detector Amplifier. In the event of an emergency, (or if more than 450 pounds of tension is placed on the cable,) a CAD (cartridge actuated device,) will automatically fire at the reeling machine and sever the cable. The CAD can also be manually triggered should the need arise or if the automatic system fails.
Signals from the towed body passed through the reeling machine are then passed through the MAD Amplifier for signal conditioning and amplification. After passing through the amplifier the composite signal is then sent to the applicable video generation system for presentation on the operator's display.
MAD is mainly used to rough out the location of a possible submerged target, after which a pattern of sonobuoys will be laid in the area, further narrowing the search field. Positive acoustic contact with the target, (either through passive/active sonobuoys or dipping/fixed array active sonar,) will be made before a weapon is launched. Most oceanographic charts used in ASW operations also have the location of iron ore bearing seamounts and other underwater structures marked to prevent erroneous prosecution of geological features.