At the request of FAA, the Federal Communications Commission last week formally halted a prohibition on the certification, manufacture, sale or use of emergency locator transmitters (ELT) that use the 121.5 MHz frequency.

FCC had called for the prohibition after the international Cospas-Sarsat organization announced in 2000 that it planned to end satellite processing of distress signals from 121.5 MHz beacons beginning in 2009. The organization had urged users to switch to more reliable 406 MHz units.

Cospas-Sarsat has since stopped monitoring the 121.5 MHz frequency, FCC says. An FCC notice of proposed rulemaking had received general support for a phaseout of 121.5, and the National Oceanic and Atmospheric Administration, the U.S. Coast Guard, the U.S. Air Force, and NASA—which administer the Cospas-Sarsat system in the U.S.—also advised users to switch to 406 MHz beacons, FCC notes.

FCC says it “reasoned that such a prohibition [of 121.5 MHz ELTs] would ‘provide safety benefits for search and rescue teams, as well as aircraft pilots, crew and passengers, while also preserving search and rescue resources for real emergencies.’” But FAA last summer petitioned the National Telecommunications and Information Administration to stay the prohibition, FCC says, noting, “FAA believes that the current supply of 406 MHz ELTs is not sufficient to replace all existing 121.5 MHz ELTs in the short term, so, given that most general aviation aircraft are required to carry ELTs, a prohibition on 121.5 MHz ELTs would effectively ground most such aircraft.”

FCC also acknowledged FAA arguments that 121.5 MHz ELTs still can be of use in locating missing aircraft, even without satellite monitoring of the 121.5 MHz, since the frequency is still monitored by the search and rescue community, including the Civil Air Patrol. Other arguments centered on the cost of equipping aircraft with 406 MHz ELTs, FCC adds.

“Under these circumstances, we believe it would be in the public interest to further consider what actions the Commission should take in light of the termination of satellite monitoring of frequency 121.5 MHz,” FCC says, adding it plans to issue another notice of proposed rulemaking seeking additional comment on the issue.

The Aircraft Owners and Pilots Association supported the move, saying a ban on 121.5 MHz ELTs could have caused a shortage of 406 MHz ELTs. The association, which had urged the agency to reconsider the prohibition, says, “This reversal is evidence that a coordinated effort from the aviation community can effect change and prevent a harmful proposal from becoming law.” The association acknowledges the benefits of the more advanced ELTs, but says the benefits must be balanced against the cost and needs of individual aircraft owners.