An Emergency Locator Transmitter (ELT) is simply a device that, when activated in the event of an unplanned landing or accident, sends out a distress signal pinpointing your location. It’s the one device that you hope you never need, but in the event that you do you want it to work perfectly.
There are several things to consider when looking at ELTs. Most older ELTs, which were notoriously unreliable, transmitted emergency signals only on the 121.5 and 243 MHz (military) frequencies. Any ELTs manufactured after December 1, 2012 must comply with the newer FAA TSO-C126a, which mandates that the ELT include the 406 MHz broadcast frequency. Having a 406 MHz ELT equipped with internal GPS or a GPS nav interface – options offered by almost all manufacturers – may mean the difference between being located almost immediately or having to wait several hours for a rescue.
If activated, automatically or manually, an ELT sends out a unique identification code combined with the helicopter registration information and location. ELTs equipped with GPS send digital long-message formats that include the latitude and longitude of the helicopter within four seconds (degrees-minutes-seconds) of the accident location, with an accuracy of better than 300 feet. Without the 406 MHz frequency and GPS, the operator would have to wait for multiple passes of LEO satellites needed to refine the accident position to a specific search area, which could conceivably take several hours.
Under the new, broad helicopter safety regulations released earlier this year by the FAA, all Part 135 operators must be equipped with an ELT that broadcasts on the 406 MHz frequency. FAA does not yet require ELTs for Part 91 ops, but putting safety first would seem to dictate their installation in almost any kind of operation, and in fact most operators are so equipped.
The ELT installed in a helicopter must be registered with COPSAS-SARSAT, the international service set up to monitor distress signals through a system of global satellites. In the U.S. this may be done through NOAA, at www.sarsat.noaa.gov, or internationally directly at www.cospas-sarsat.org. In 2009, COPSAS-SARSAT stopped monitoring the older 121.5 and 243 MHz distress signals, and now monitors only the 406 MHz beacon, which has become the internationally recognized distress frequency.
Battery life is, obviously, important. FAA regulations require ELT batteries to be replaced after one hour of operation or after 50 percent of the battery’s useful life. The one-hour usage requirement is cumulative, meaning that if the battery is used for 30 minutes at one point, then for 30 minutes at another point, it must be replaced.
Under FAR 91.207(d), an ELT must be inspected once every 12 months for proper installation, battery corrosion, proper functioning of the switches, and antenna signal strength. Most operators take care of this during the annual inspection.
Operators flying internationally, including in Mexico and Canada, must have the ICAO standard 406 MHz ELT.
ACK produces two ELTs for the rotary wing market, the E-O4, and its newest model, the E-04C, which has been in production for about three years and was designed specifically for the more demanding commercial market. The remote control panel is designed to fit in most avionics panels. It includes GPS and comes with a two-year warranty.
ACR/Artex offers three ELTs for helicopters: the C406-1 HM, C406-2 HM, and the C406-N HM. The Artex C406-N HM is a single-output ELT with a built-in navigation interface that integrates with onboard avionics. Navigation data is input continuously into the ELT, and the latitude and longitude of the helicopter are available immediately for a faster rescue. With the use of an optional programming adapter, the ELT can be programmed with the aircraft’s 24-bit address for fleet operators, as well as additional custom programming.
Ameri-King manufactures three models of ELTs for rotary wing use. All of them broadcast on the three standard frequencies, 121.5, 243, and 406 MHz; the flagship model AK-451 also includes a GPS interface. The AK-451 ELT GPS/NAV interfaces with Garmin, Honeywell, BendixKing, Trimble Nav, Arnav, and II Morrow avionics.
Emergency Beacon produces two primary models of ELTs for helicopters. The EBC 406 APH is designed for installation in the cockpit or cabin area and requires an external antenna but does not need the cockpit panel interface. The EBC 406AFH is electronically the same as the APH but is designed for stowage in the baggage area or tail section of the aircraft and requires the panel interface. Both units transmit on the 121.5 and 406 MHz frequencies.
Emerging Lifesaving Technologies is a joint venture with Sparrow Avionics and Kelly Manufacturing founded in 2008. The company manufactures one ELT for general aviation applications, the ELT406GPS, which includes a built-in GPS module, and as the name implies broadcasts solely on the 406 MHz frequency. The transmitter and the panel-mounted remote switch/indicator can, in most cases, interface with existing cockpit hardware. The blade antenna is used for both the 406 MHz transmission and GPS signal.
Honeywell has manufactured more than 30,000 ELTs over the past 30 years. The RESCU 406 AFN2 is its newest generation ELT, which includes an internal navigation input (ARINC 429) module and an optional Aircraft Identification Module (AIM). The AIM automatically reprograms the transmitter; it does not have to be removed from the helicopter for reprogramming. The AFN2 interfaces with the helicopter maintenance/warning systems, remote panel/switch, AIM, antenna and remote audible alarm. Honeywell also offers a global product support network.
The Techtest 503 ELT transmits on 121.5 MHz, 243 MHz and 406 MHz. GPS is an option either as an interface with the ELT or as an embedded stand-alone system as part of the unit. The 503 may be operated remotely with extended range operation, and the transmitter portion of the 503 can be easily removed for use as a portable Personal Locator Beacon.
Kannad makes ELTs for commercial, general aviation and military applications. Its flagship model, the Integra 406 AF-H, which is specifically designed for helicopters, includes an internal GPS and an internal 406 MHz antenna. With the internal antennas, the ELT may be used separately from the aircraft without having to add an auxiliary antenna. Kannad’s nav interface provides a second, redundant GPS positioning source, which helps in transmitting the position of the aircraft in real time.
The Pointer Model 8000-1 ELT has six interchangeable modules, facilitating repair and/or reprogramming. The unit broadcasts on 121.5 and 406 MHz, and FAA certification for an internal GPS is expected late in 2014. A cockpit panel monitor/switch is supplied with all models to provide test, reset and RF/battery status indicators as required by RTCA DO-204A. A lifetime warranty on materiel and workmanship is standard.
Related: Mission Equipment