As a student pilot, and then again as a renter of small airplanes, I always took comfort when I got to the checklist item that reminded me to arm the emergency locator transmitter (ELT). It was good to know that, if the worst happened, a radio signal would automatically beam into space, as we always see in the movies, and the rescuers would promptly appear over the horizon to save me.
When I needed a new ELT for my 1952 Piper Super Cub restoration project, I learned what ELT might really mean: Many ELTs are of little use in an Emergency, can’t Locate a downed aircraft with any accuracy, and often Transmit only by mistake.
Huge advances in determining your position on Earth have been made in recent years—your smartphone knows which street corner you’re standing on and can display the breakfast menu of a restaurant there. Yet it may be decades-old technology on which you’ll rely when flying many older aircraft.
ELTs are designed to send a radio signal when triggered by the G forces of a crash, or manually by the pilot. This distress signal is received by an international Cospas-Sarsat Program satellite; the search and rescue system—developed by Canada, France, Russia, and the United States—became operational in 1982. The satellite relays the signal to a ground station, which notifies the appropriate nation’s search and rescue organization. The rescuers then use land-based and airborne equipment to locate the downed aircraft and send in the rescue crew.
Originally, the system was designed to locate downed aircraft equipped with ELTs and ships in distress with maritime emergency position-indicating radio beacons. In 2003, personal locator beacons, for people, were added to the system.
Since the system’s inception, Cospas-Sarsat has assisted in the rescue of more than 37,000 people. It was a great advance from the 1980s when, in many instances, the first report that a general aviation airplane was missing came from a worried family member. That could be many hours after an accident. Then, the rescuers only knew the overdue aircraft might be found anywhere between the departure airport and an intended destination.
Many were never found.
The system did have its flaws. Only 60 percent of the Earth’s surface was covered because a satellite had to be in direct sight of the activated ELT and a ground station at the same time. The satellites couldn’t store the ELT’s location and then forward the information to a ground station later in the orbit.
The early ELTs sent signals on 121.5 MHz and 243.0 MHz, the standard civil and military aviation emergency frequencies, which allowed for a great amount of interference. False alarms were common, wasting vital search and rescue resources. There were so many false alarms that it was common to wait for a distress signal to be confirmed by a second satellite, which could delay dispatch of search and rescue teams for hours. A pilot injured in a crash could expect to wait a long time for help to come.
Also, the signal’s source could be located only to a 12-mile radius, which narrowed the search area to about 450 square miles. However, even this flawed system is not available today to pilots flying many older aircraft, and that includes most rental aircraft—those satellites are no longer listening.
In the 1990s a new ELT system was developed to improve the locating accuracy and reduce false alarms. It uses 406 MHz—a frequency reserved exclusively for emergency beacons—and sends a discrete signal that identifies each ELT and the aircraft it’s registered to. When a distress signal from a 406 MHz ELT is received, the authorities notify search and rescue, while simultaneously contacting the ELT’s registered owner. Any false alarms can be quickly confirmed. The latest 406 MHz ELTs can also be paired with a GPS receiver that sends position data accurate to 100 yards, the length of a football field. That beats 450 square miles by a—well, about 450 square miles.
As of 2009, only signals from 406 MHz ELTs are detected by the Cospas-Sarsat system. The 121.5 MHz and 243.0 MHz ELTs are detectable only by ground-based receivers and aircraft.
Many older aircraft—and that includes most of the rental fleet—still carry the old 121.5 MHz ELTs. Students and renters need to use other strategies to ensure they can be located in the event of an unplanned, off-airport landing. As with most aspects of aviation, multiple backups are best, and each pilot must consider his own specific flying situation. A student pilot flying in a designated practice area might adopt a strategy like this.
• Ensure that the ELT on board is properly installed and working correctly.
• All students should inform the FBO or instructor of their flight plan, even if it’s “I’m just going out to the practice area.” Keep in radio contact on some frequency, at least to listen and have available for a mayday call.
• Keep a cellphone within reach in the cockpit. Dialing 911 is the quickest way to get help if you’re trapped in the aircraft, or you’ve had to abandon the airplane after an off-airport landing. Keep it in a pocket so it goes with you during the emergency and doesn’t become lost in the wreckage.
• For cross-country flights, a student also should file a flight plan and request VFR traffic advisories, more commonly known as flight following, from air traffic control. It’s always good if someone in the system knows who and where you are.
• Finally, if any flights are made in sparsely populated or rugged country, where cellphone coverage may be limited, it would be smart to carry a personal locator beacon. They cost less than $300; that’s a lot of comfort for little cash. Many PLBs are so small that one could comfortably be kept in a pocket at all times while flying. If you’re flying over some of the United States' truly vast wilderness, such as Alaska, you might even want a satellite phone.
For students and airplane renters, keep all these factors in mind when you accomplish “ELT armed” on your preflight checklist. A decades-old ELT may not help you in an emergency. You need to develop your own plan: cellphone, flight following, PLB.
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