ELTs

Those first ELTs, produced under FAA technical standard order (TSO) C91, failed to activate in a crash more than 75 percent of the time. When they did activate, according to AOPA, 97 percent of the time it was a false alarm. By 1985, when the FAA revised the standards and came up with TSO-C91a, a lot of the bugs had been worked out, but the ELTs troubled history painted it with a mostly deserved reputation for unreliability. Those earlier devices still meet the FAAs requirement to carry an ELT (see the sidebar on the bottom of the opposite page), but it perhaps is time they were retired in favor of newer technology.

Sunday, September 30, 2018 at 12:00 AM ET

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Key Takeaways:

Early emergency locator transmitters (ELTs) had a troubled history of unreliability, frequently failing to activate in crashes, and generating numerous false alarms.
Modern 406 MHz ELTs (TSO-C126b) represent a significant technological improvement, offering greater reliability, more precise location data, and faster rescue capabilities.
Despite advancements, false alarms persist, often due to improper testing methods for 406 MHz ELTs, which can alert search and rescue satellites.
The article strongly advocates for general aviation pilots to upgrade to 406 MHz ELTs, emphasizing their superior safety benefits and efficiency in search and rescue operations over older, legally compliant models.

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The emergency locator transmitter, or ELT, has long been one of the most problematic devices regularly carried aboard general aviation aircraft. When first mandated in the early 1970s, there weren’t enough of them available to equip the fleet, and replacement parts and batteries were scarce. Nevertheless, the FAA was interpreting the law mandating them to mean an aircraft without a working ELT wasn’t airworthy. Hilarity ensued.

Those first ELTs, produced under FAA technical standard order (TSO) C91, failed to activate in a crash more than 75 percent of the time. When they did activate, according to AOPA, 97 percent of the time it was a false alarm. By 1985, when the FAA revised the standards and came up with TSO-C91a, a lot of the bugs had been worked out, but the ELT’s troubled history painted it with a mostly deserved reputation for unreliability. Those earlier devices still meet the FAA’s requirement to carry an ELT (see the sidebar on the bottom of the opposite page), but it perhaps is time they were retired in favor of newer technology.