This SAE Aerospace Standard (AS) covers ULDs utilized in finding submerged aircraft. Such ULDs are installed within the aircraft in a manner that they are unlikely to become separated during crash conditions. The low frequency ULD should be attached to the airframe in accordance with the manufacturer’s recommendations in order to maximize the underwater detection range. ARINC Standard 677 also provides installation guidance for Low Frequency ULDs.
Technology exists to increase the minimum Low Frequency Underwater Locating Devices (ULD) operating life without changes to the form, fit or general function of an installed ULD. For aircraft search and recovery in extremely remote areas, a Low Frequency ULD operating for 30 days may not be sufficient. This revision includes an increase of the minimum operating life in 4.7 from 30 to 90 days along with an added reference to the recently published ARINC Standard 677 regarding the installation of the ULD on aircraft.