The Advisory Circular mentioned earlier is in the process of being superseded by AC 20-141A which provides Federal Aviation Administration (FAA) information on certification (design and installation) and continued airworthiness of digital flight data recorder systems (DFDRS). The intent is to enable the National Transportation Safety Board (NTSB) in the United States to conduct more thorough investigations of accidents and incidents. The data recorded is also available to industry to enable the prediction of trends that may be useful in determining modifications needed to avoid accidents and incidents.
Emergency locator transmitters
The Emergency Locator Transmitter (ELT) was another thought for an article topic that came to mind. After all, regulatory mandates have prompted an FAA recommended installation of 406 MHz ELTs because of the pending loss of satellite coverage of the older 121.5 MHz ELTs in 2009. The new 406 MHz ELT design has several advantages over the previous generation and includes more transmitter power, digitally encoded aircraft/owner identification and can provide position information which helps the Rescue Coordination Centers (RCC) either find the aircraft or resolve false alerts. If you install a 406 MHz ELT in an aircraft or purchase an aircraft with a 406 MHz ELT it is important that the device be registered with National Oceanic and Atmospheric Administration (NOAA). To help aircraft owners register their 406 MHz ELTs with NOAA, various FAA Headquarters Internet homepages provide a link to NOAA’s 406 MHz ELT registration web site.
When a distress beacon, whether a marine, aviation, or personal, is detected by a satellite in the U.S. area of responsibility, NOAA processes the alert and forwards the information to the appropriate authorities. In the United States, the U.S. Air Force Rescue Coordination Center (ARFCC) or one of the U.S. Coast Guard Rescue Coordination Centers (CGRCC) will be notified as appropriate.
NOAA has announced the termination of the satellite-based alert monitoring of 121.5 MHz distress beacons in 2009 due in part to the high false alert rate. After that date, the satellite system will only monitor and process 406 MHz distress alerts.
About 99 percent of the 121.5 MHz distress alerts are false transmissions.
Because of this high false alert rate, rescuers normally wait for either extra satellite passes over the alert area or some other verification of a real distress before activating a search and rescue (SAR) response. This delay can mean hours before a SAR mission is initiated. In contrast, the response to a 406 MHz distress alert can be a matter of minutes. The key to this responsiveness is the 406 MHz beacon registration requirement. Since a 406 MHz beacon transmits its own unique digital identification code, the registered owner can be contacted for verification of an actual alert or asked to turn off a faulty 406 MHz beacon.
Well, I hope some tangible ideas for an article come to mind soon as the submission deadline for this issue is rapidly approaching and the earlier feeling of impending doom is growing stronger.
Jim Sparks has been in aviation for 30 years and is a licensed A&P. His career began in general aviation as a mechanic, electrician, and avionics technician. In addition to extensive hands on, Jim created and delivered educational programs for several training organizations and served as a technical representative for a manufacturer of business jets. Currently when not writing for AMT, he is the manager of aviation maintenance for a private company with a fleet including light single engine aircraft, helicopters, and several types of business jets.
After Feb. 1, 2009, the world-wide Cospas-Sarsat satellite system will no longer process 121.5 MHz alert signals.
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