121.5

As you should know, the international consortium concerned with relaying electronic distress signals stopped monitoring the 121.5 MHz frequency on February 1, 2009, in favor of emergency locator transmitters (ELTs) and other devices transmitting on 406 MHz. Since the FAA does not require operators to upgrade to the new standard, the practical impact of this action was to obsolete older ELTs and make it more difficult to find a downed aircraft lacking the 406 MHz technology. In 2011, the U.S. Federal Communications Commission (FCC) proposed prohibiting use of an ELT capable of transmitting only on 121.5 MHz (the 406 MHz ELT standard includes 121.5 MHz signals). Mayhem ensued, and the FCC eventually backed down, in part thanks to FAA and AOPA input.

Joseph E. (Jeb) Burnside

Tuesday, February 19, 2013 at 12:00 AM ET

Verified

Key Takeaways:

International monitoring of 121.5 MHz distress signals stopped in 2009, shifting focus to 406 MHz ELTs, though older 121.5 MHz devices are not federally required to be upgraded.
The FCC is currently proposing to prohibit the future manufacture, importation, and sale of 121.5 MHz-only ELTs, and is seeking public comment on whether their continued use should also be banned.
The author criticizes the FCC's proposed rulemaking, questioning the overall usefulness of ELTs given newer technologies and arguing that 121.5 MHz ELTs can still function while 406 MHz ELTs also have reliability issues.

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In 2011, the U.S. Federal Communications Commission (FCC) proposed prohibiting use of an ELT capable of transmitting only on 121.5 MHz (the 406 MHz ELT standard includes 121.5 MHz signals). Mayhem ensued, and the FCC eventually backed down, in part thanks to FAA and AOPA input. Since then, the FAA has canceled TSO C91a, the document specifying 121.5 MHz ELT standards, effectively preventing new 121.5-only ELT approvals. Previously certified ELTs may still be produced, marketed and installed, however.