Emergency Locator Transmitter Flashcards
Emergency Locator Transmitter (ELT)
● This is a transmitter that broadcasts a distress signal in the event of a sudden deceleration which is most likely to happen in the event of an accident.
● ELTs emit a loud siren like signal on 121.5 and 243 MHz.
● On 406 Mhz they transmit a coded signal of the ELT so the serial number can be matched so search and rescue can tell who’s ELT is it.
● 406 ELT signals are transmitted to Search and Rescue satellites which will then calculate and indicate a search area.
406 Mhz ELTs
● The 406 Mhz ELT is the new standard for ELTs and is replacing the older 121.5 / 243 MHz ELT.
● This type of ELT transmits a far more powerful signal of 5 watts, as opposed to the 25 milliwatts signal of the 121.5 MHz ELT. CAR 605.38.1
● A GPS enabled 406 MHz ELT will also transmit a “burst of data” every 50 seconds that will include the serial number, which is linked via a database to a specifically registered aircraft, and the latitude and longitude of the unit
Location of the ELT
● Typically, the ELT looks like an orange or yellow plastic box
● It is usually located in the tail of the aircraft.
Types of ELT
● A or AD: Automatic or Automatic Deploy
● F or AF: Fixed or Automatic Fixed
● AP: Automatic Portable
● P: Personal
● W or S: Water-Activated or Survival
Testing an old style 121.5 MHz ELT
● Testing of an ELT must be done only during the first 5 minutes of any UTC hour.
➢ Testing is further restricted to a duration that does not exceed 5 seconds.
● If it is accidentally triggered in flight then the sheer power of the ELT’s broadcast will likely “wash-over” the other frequencies on the aircraft’s radio.
● This is why before shutdown it is recommended to check 121.5 MHz for any ELTs that may have been activated.
Testing a 406 MHz ELT
● All 406 MHz ELTs and their cockpit remote switch should be tested in accordance with the manufacturer’s instructions.
● All 406 MHz beacons are equipped with a self-test function, which also checks the power output of the 121.5 MHz transmitter
● The digital signals from 406 MHz ELTs are detected almost immediately by COSPAS-SARSAT Geo Satellites (GEO).
● Selection of the “ON” position for more than 50 seconds will result in an alert being routed directly to the nearest Joint Rescue Coordination Center (JRCC), it will be interpreted as a real emergency
ELT Requirements
● All aircraft that are operated more than 25 NM from home base require an ELT.
● Exemptions to this rule:
➢ Gliders
➢ Balloons
➢ Airships
➢ Ultra-Lights
➢ Gyroplanes
➢ Large Commercial Jets
ELT Operating Instructions
● The three-way toggle switch of an ELT has three settings
➢ OFF － Will not activate
➢ ARM － Will activate in the event of an accident
➢ ON － Transmitting
ELT Operating Instructions In an Emergency
● A general aviation ELT contains a G-sensor that detects the deceleration associated with a crash, such deceleration automatically activates the transmitter.
● Despite that, after an incident in which you will need search and rescue, it is best to assume that the automatic activation feature has failed.
➢ Place the ELT function switch to the ON position as soon as it is possible.
➢ Remember to brief your passengers on how this works
● Do NOT delay an ELT activation until after the flight plan expires, such a delay will only cause the rescue to be delayed as well.
● Once the ELT is turned ON do not turn it OFF, this will only hamper the rescue and homing efforts!
● If the emergency locator transmitter (ELT) is a portable model with its own auxiliary antenna, and can be safely removed from the aircraft, it should be placed as high as possible on a level surface to reduce obstructions between it and the horizon.
● Raising an ELT from ground level to 2.44 m (8 ft) may increase the range by 20 to 40 percent.
● The antenna should be vertical to ensure optimum radiation of the signal.
● Placing the transmitter on a piece of metal, or even the wing of the aircraft, if it is level, will provide the reflectivity to extend transmission range
● Holding the transmitter close to the body in cold weather will not significantly increase battery power output.
➢ In addition, as the body will absorb most of the signal energy, such action could reduce the effective range of the transmission
Unserviceable ELT
● If an ELT becomes unserviceable the aircraft may be operated for up to 30 days provided:
➢ The ELT is removed at the first aerodrome at which repairs or removal can be accomplished.
➢ The ELT is promptly sent to a maintenance facility.
➢ A placard is displayed in the cockpit stating that the ELT has been removed and the date of the removal
121.5 ELT Maintenance
● ELTs powered by non-water-activated batteries shall be maintained at intervals not exceeding twelve months.
● ELTs powered by water-activated batteries shall be maintained at intervals not exceeding five years.
● ELT batteries shall be maintained at the interval recommended by the ELT manufacturer.
● Maintenance is done by a avionics technician
406 and 121.5 ELT Maintenance
● ELTs powered by non-water-activated batteries shall be maintained at intervals not exceeding:
➢ 12 months, in accordance with the applicable operational test requirement, and
➢ 24 months, in accordance with the applicable performance test requirement.
● ELTs powered by water-activated batteries shall be maintained at intervals not exceeding five years.
➢ ELT batteries shall be maintained at the interval recommended by the ELT manufacturer
● Operational test: Conducted by an operator.
➢ Usually self test on ELT
● Performance test requirement conducted by avionics technician
Accidental ELT Transmissions
● Always check the ELT by tuning 121.5 MHz at the end of every flight.
● To prevent an unnecessary Search and Rescue mission, all accidental ELT activations should be reported as soon as possible to the nearest ATS unit.
● This report should include
➢ Location of the transmission.
➢ Time.
➢ Duration
