Fort Myers, FL - 1990. A mechanic on a late night flight, hoping to have a commuter aircraft ready to go by morning, augered in a half mile short of the runway. The accident was survivable. The pilot, however, bled to death while waiting. The plane was not found until the next afternoon, when it was spotted by the pilot of an inbound aircraft.

The mechanic/pilot had filed a VFR flight plan and squawked 1200. A search was initiated. The search and rescue teams listened for an ELT signal on 121.5 at and around the airport, but none was heard. The aircraft wasn’t observed because it had crashed into a low lying area just a half mile short of the runway. The ELT on board the aircraft was functional but did not activate.

Taos, NM - 1979. On a VFR Flight, a doctor and his family on their way from Texas to a ski resort in Colorado were trapped in a mountain canyon by snowstorms and impacted the side of the 12,000 MSL mountain at about 9000 feet. No flight plan had been filed, and the transponder was not turned on. An ELT signal was heard, but site coordinates were mixed up somewhere before field dissemination and search and rescue took place in the wrong canyon!

The ELTs installed on many general aviation aircraft—those approved under TSO-C91—often fail to operate properly or to activate at all. Some reports suggest a failure rate as high as 97.44% and a false alarm rate of 95.7%. TSO-C91a addresses some of the problems associated with the older units by requiring the internal and external antennae to be triggered in case of activation, by hard mounting the unit to the structure to better withstand crash forces, and with the incorporation of a “bump and recoil” activation system as well as a cockpit remote activation switch. TSO-C91a is now mandatory on new aircraft and when an ELT is replaced.

While these fixes may help, they are not perfect. Everyone has heard about the recent infamous crash off of Martha’s Vineyard. 1979, 1990, 1999—and the same problems plague search and rescue operations. Even the best, most up-to-date equipment is not infallible. Do everything you can to help search and rescue locate your aircraft in case of a crash. File a flight plan, turn on your transponder, and get flight following; ATC is there, use it.

Don’t bet your life on your ELT!

“Professor A.K. Cydent” is an ex-FAA Investigator and Army Rotorcraft Instructor who may have more answers to accident-related questions than we thought possible.