A320 Emergency Location Transmitter

REVISION 1 - MAY 2008

INTIAL ISSUE - MAY

2008

REVISION 1 - MAY 2008

INTIAL ISSUE - MAY

2008

AIRBUS

A319/A320/A321

EMERGENCY

LOCATOR

TRANSMITTER

(ELT)

AIRBUS

A319/A320/A321

EMERGENCY

LOCATOR

TRANSMITTER

This document, compiled by Royal Brunei Technical Training, is used

with instructor guidance as the course material for the stipulated

training purpose.

Once issued, its contents will not be updated and under no

circumstances shall it be used as a reference for aircraft maintenance

or operational activities.

This document or part of it shall not be copied or reproduced in any

form without permission from Royal Brunei Airlines Sdn Bhd.

2008 - Royal Brunei Airlines



training purpose.

Once issued, its contents will not be updated and under no

circumstances shall it be used as a reference for aircraft maintenance

or operational activities.

This document or part of it shall not be copied or reproduced in any

form without permission from Royal Brunei Airlines Sdn Bhd.

2008 - Royal Brunei Airlines



AIRBUS A319/A320/A321 EMERGENCY LOCATOR

TRANSMITTER (ELT)

REVISION 1 MAY 2008

i

TABLE OF CONTENTS

TOPIC PAGE

1. ELT FUNDAMENTALS ........................................................................................................ 1

PURPOSE .......................................................................................................................... 2

TRANSMISSION FREQUENCIES ......................................................................................... 2

OPERATION ..................................................................................................................... 2

COSPAS-SARSAT .............................................................................................................. 3

406MHZ TRANSMISSION PRECAUTIONS ........................................................................... 4

TESTING........................................................................................................................... 4

PROGRAMMING DONGLE ................................................................................................ 5

MAINTENANCE DONGLE ................................................................................................. 5

2. A320 FAMILY FIXED ELT ................................................................................................. 6

COMPONENTS ................................................................................................................. 7

ELT ................................................................................................................................... 8

ELECTRICAL INTERFACE ................................................................................................. 9

ADPTER CABLE (141MX) ................................................................................................. 10

ANTENNA (112MX) .......................................................................................................... 10

MAINTENANCE DONGLE ................................................................................................ 11

REMOTE CONTROL PANEL (11MX) ................................................................................. 11

OPERATION .................................................................................................................... 12

CONTROLS AND INDICATIONS ON ELT .......................................................................... 13

CONTROLS AND INDICATIONS ON RCP ......................................................................... 14

3. A320 FAMILY PORTABLE ELT ......................................................................................... 15

REVIEW QUESTIONS ....................................................................................................... 16

REFERENCES .................................................................................................................. 16


TRANSMITTER (ELT)

REVISION 1 MAY 2008

ii

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TRANSMITTER (ELT)

REVISION 1 MAY 2008

1

1. ELT FUNDAMENTALS


TRANSMITTER (ELT)

REVISION 1 MAY 2008

2

PURPOSE

The Emergency Locator Transmitter (ELT) is activated to emit

distress signals on emergency frequencies. This signal is used by

search-and-rescue teams to reach the distressed.

COSPAS-SARSAT, a satellite based search and rescue system has

made it possible to give a unique identity to a user and to locate

the person geographically in the event of a transmission.

TRANSMISSION FREQUENCIES

The ELT system transmits on 3 frequencies:

121.5 MHz (Civil)

243 MHz (Military)

406 MHz (COSPAS-SARSAT)

OPERATION

AN ELT is activated manually or automatically. Auto-activation is

usually with a water-activated switch or a g-switch. A g-switch is

activated by the high impact forces created in an aircraft crash.

The ELT is powered by batteries for independent operation.

The 121.5/243 MHz transmitter transmits a "sweep" distress signal

for more than 48 hours. The distress signal transmits continuously

with an output power of 100 mW on each frequency.

The 406 MHz transmitter transmits a digital signal for 24 hours. The

digital signal is a message of 122 bits (aircraft identification)

transmitted every 50 seconds for 440 msec. The first transmission

starts after 50 seconds.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

3

COSPAS-SARSAT

Launched in the early eighties by the four founder countries

(Canada, France, Russia, and the USA), the COSPAS-SARSAT

system provides satellite aid to search and rescue (SAR) operations

for maritime, aeronautical and terrestrial vehicles anywhere in the

world.

COSPAS-SARSAT uses a constellation of Low Earth Orbit (LEO) and

Geostationary Orbit (GEO) satellites which relay the 121.5 / 243

MHz signals and process the 406 MHz signal to ground stations

(LUT) where the beacon positions are determined with a precision

of 10 NM with 121.5 / 243 signals and less than 2 NM with 406

signals.

The satellite system transmits the 406 MHz distress signal to a Local

User Terminal (LUT), when the LUT is in range. The LUT receiving

range is a radius of approximately 2.500 km (1367.00 NM). When

the LUT is not in receiving range, the satellite system stores the

distress signal until transmission is possible. The LUT automatically

processes the distress signal to identify and show the position of

the aircraft to a radius of approximately 1.8 km (5900.00 ft.). The

processed data is transmitted to a Mission Control Centre (MCC).

The MCC sends the data to an applicable Rescue Coordination

Centre (RCC), where Search and Rescue (SAR) operations are

started. The 121.5 MHz and 243 MHz signals are used to find the

aircraft in the final stage of SAR operation.

Once activated, the transmitter operates continuously on 121.5 and

243 MHz. The output power is 100 mW on each frequency.

The modulation is an audio frequency sweeping downwards from

1420 Hz to 490 Hz with a repetition rate of 4 Hz. The AM modulation

factor is over 85%.

During the first 24 hours of operation, a signal is transmitted on 406

MHz every 50 seconds to the COSPAS-SARSAT satellites. The

output power on 406 MHz is near 5W i.e. 50 times more powerful

than the VHF signal. Phase modulation at 400 bps enables

transmission of all the relevant identification information to the

COSPAS-SARSAT satellites in less than half a second.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

4

406MHZ TRANSMISSION PRECAUTIONS

Activating a 406 MHz beacon will generate a COSPAS-SARSAT

distress alert message that will be relayed to Search and Rescue

Services for their immediate action. Therefore, 406 MHz beacons

should not be activated except in real distress situations or unless

special prior arrangements have been made with the COSPAS-

SARSAT Mission Control Centre (MCC) that services your region.

Activating a beacon for reasons other than to indicate a distress

situation or without the prior authorization from a COSPAS-SARSAT

MCC is considered an offence in many countries of the world, and

could result in prosecution.

406 MHz beacons are designed with a self-test capability for

evaluating key performance characteristics.

Initiating the beacon self-test function will not generate a distress

alert in the COSPAS-SARSAT System.

However, it will use some of the beacon's limited battery power,

and should only be used in accordance with the beacon

manufacturer's guidance.

If you inadvertently activate the beacon in its operational mode,

contact the nearest COSPAS-SARSAT MCC as soon as possible.

As 406 MHz transmission is effective 50 seconds after the ELT

activation, if it is reset within this delay, no further radio contact

will be necessary.

The contact details for COSPAS-SARSAT MCCs throughout the

world are published in the COSPAS-SARSAT Data Distribution Plan,

document C/S A.001, Annex II/A ,which can be downloaded free of

charge.

Requests to conduct a live beacon test should be directed to the

COSPAS-SARSAT Mission Control Centre that services the location

in which the test is planned.

There are currently 430,000 COSPAS-SARSAT 406 MHz distress

beacons in operation. In view of the number of beacons in service,

coupled with the effort and resources required to coordinate a live

beacon test, beacon owners should be aware that authorization to

activate a beacon for testing will only be granted in exceptional

circumstances.

TESTING

Any test transmission of an ELT must be conducted only during the

first 5 minutes of any UTC hour and restricted in duration to not

more than 5 seconds.

During testing the aircraft VHF radio is tuned to 121.5 MHz.

Reception of the swept tone is confirmation that the transmission is

active.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

5

PROGRAMMING DONGLE

Aircraft identification is programmed in the ELT using a

programming dongle.

When an unprogrammed ELT is installed, connected to the

programming dongle, and is switched to "ARM", it automatically

updates its own memory with the identification data contained in

the programming dongle memory.

The programming dongle remains on board the aircraft.

When the ELT is removed from the aircraft, it keeps its

identification data.

MAINTENANCE DONGLE

For maintenance purposes, it is possible to delete the identification

information of the ELT by connecting a maintenance dongle to the

ELT. Any accidental transmission with this maintenance dongle will

not initiate SAR operation as the identification code transmitted is

recognized by COSPAS-SARSAT as "not on board".

Programming dongle


TRANSMITTER (ELT)

REVISION 1 MAY 2008

6

2. A320 FAMILY FIXED ELT


TRANSMITTER (ELT)

REVISION 1 MAY 2008

7

COMPONENTS

The ELT system has:

An ELT (110MX),

An adapter cable (141MX) and programming-dongle connector (110MX-A),

A remote-control panel (RCP) (111MX),

An antenna (112MX),

A Mounting bracket (140MX).


TRANSMITTER (ELT)

REVISION 1 MAY 2008

8

ELT

The ELT is installed in a bracket, held in position with two buckles

and straps, with the interface in flight direction. The bracket is

installed above a ceiling panel 261BC in the AFT utility area. The

bracket has three location holes, two straps and placards

(Identification and Flight direction). The has an aluminium-alloy

casing which is orange-coloured. The casing has two parts (base

plate and housing) that are attached together by screws, washers

and an O-ring, and includes these components:

Placards attached to the casing (Identification, Strap, Instruction, Type and Battery),

An electronic board,

A three cell battery-pack,

A two cell battery-pack,

An interface,

An auxiliary-antenna (referred to as antenna),

A tether.

The base plate is divided into two compartments by a partition,

with a hole for the electrical cable connection between the battery-

packs and the electronic board. The bottom face of the base plate

has three locking pins. The electronic board is installed in the front

half (flight direction) by screws and washers. The battery-packs

are installed in the rear half on a foam wedge, and covered by a

heat-shrink sheath.

The housing is divided into two compartments by a partition. The

front half (flight direction) has the electrical cables that connect the

interface to the electronic board. The rear half has a foam wedge to

prevent damage to the battery-packs.

The antenna is folded back on itself and kept in loops on the straps,

when the ELT is installed in the aircraft. When you remove the

antenna, it will spring quickly back to a straight position. The

antenna is attached to the housing by a stainless-steel cord. The

tether is attached to a strap, and together with the antenna is used

in portable mode.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

9

ELECTRICAL INTERFACE

The interface, on the front face of the housing includes

An RCP connector,

An ANT connector,

A RED indicator,

An ON/OFF/ARMED switch.

The RCP connector is used to connect:

An RCP,

Programming and test equipment.,

An adapter cable (141MX) and programming-dongle connector (110MX-A) (if installed),

Maintenance-dongle.

For transmission on board, the ELT is connected to the antenna

fixed on the fuselage. Alternatively, the auxiliary antenna can be

connected to the same connector for using the ELT in portable

mode.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

10

ADPTER CABLE (141MX)

The programming-dongle programs the ELT with the aircraft

identification and country code.

To programme the ELT, connect the programming-dongle to the

RCP connector on the ELT through the adapter cable (141MX), and

set the ELT ON/OFF/ARM switch to the ARM position. The ELT

memory is automatically updated with the data stored in the

programming-dongle memory.

The adapter cable is attached to the bracket, which is installed

above the ceiling panel 261BC in the AFT utility area. The ELT is

installed in the bracket and the programming-dongle connector is

connected directly to the ELT RCP connector. The connector at the

other end of the adapter cable is connected to the connector from

the RCP. The adapter cable is approximately 200 mm (7.87 in.)

long.

ANTENNA (112MX)

The antenna is installed on the upper external fuselage between

FR64 and FR65 and held in position with six screws. It transmits

three-frequency omni-directional signals when the ELT operates.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

11

MAINTENANCE DONGLE

The maintenance-dongle has a maintenance identification data (ID)

code programmed in its memory. When you replace the ELT, the

removed ELT keeps its ID, which is necessary in portable mode. To

prevent two ELTs with the same ID, you must program the removed

ELT with the maintenance-dongle. A RED "Remove before flight"

streamer is attached to the maintenance-dongle. If you accidentally

operate an ELT with a maintenance ID, the signal will be ignored

by the satellite system, and SAR operations are not started.

REMOTE CONTROL PANEL (11MX)

The ELT can be controlled from the Remote Control Panel (RCP)

located on the overhead panel in the cockpit.

To enable the RCP control, the ON/OFF/ARM switch on the must be

in the ARM position.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

12

OPERATION

The ELT transmits distress signals, installed in the aircraft, or used

in portable mode. When the ELT is installed, it can be operated

automatically or manually. When you use the ELT in portable mode

it is operated manually. In portable mode you connect the antenna

to the ANT connection on the ELT. You must remove the antenna

carefully from the loops on the straps, because it is folded, and will

spring quickly back to a straight position. In an emergency over

water you remove the tether from the strap and attach it to a life

raft.

The two battery-packs supply the power to operate the ELT,

installed in the aircraft, or used in portable mode. The 3 cell

battery-pack supplies power to the electronic board which

includes the G-switch, and the 2 cell battery-pack supplies power

to the G-switch.

The 121.5/243 MHz transmitter transmits a "sweep" distress signal

for more than 48 hours at -20.0 deg C (-4.00 deg F) in automatic or

manual operation. The distress signal transmits continuously with

an output power of 100 mW on each frequency. The transmission

starts immediately after the BITE test sequence is completed.

The 406 MHz transmitter transmits a digital signal for 24 hours at -

20.0 deg C (-4.00 deg F) in automatic or manual operation. The

digital signal is a message of 122 bits (aircraft identification)

transmitted every 50 seconds for 440 msec. The first transmission

starts after 50 seconds.

AUTOMATIC OPERATION

When the ELT is connected to its system in the aircraft, and the G-

switch detects an impact sufficient to start transmission.

MANUAL OPERATION

When the ELT is connected to its system in the aircraft and the G-switch is not triggered, but a signal must be

transmitted (aircraft out of operation, injured

passengers/crew members).

When the ELT is connected to its system in the aircraft and you do a self-test (BITE).

When the ELT is disconnected from its system, removed from the aircraft and used in portable mode.

ACCIDENTAL OPERATION

When the ELT is connected to its system in the aircraft, and the G-switch starts transmission without a real emergency

(hard landing).


TRANSMITTER (ELT)

REVISION 1 MAY 2008

13

CONTROLS AND INDICATIONS ON ELT

The ON/OFF/ARM switch has these functions:

Set to the ON position for manual operation of the ELT. When you

set the ON/OFF/ARM switch to the ON position, the BITE test

operates automatically before transmission starts.

Set to the OFF position:

When the ELT is connected to its system in the aircraft and requires maintenance, or is parked for a long time.

When the ELT is disconnected from its system and removed from the aircraft.

To stop transmission.

Set to the ARM position for automatic operation of the ELT. When

you set the ON/OFF/ARM switch to the ARM position from the OFF

position the BITE test operates automatically.

The RED indicator and buzzer operate when the ELT operates, or to

indicate the BITE test result.

When the ELT operates:

The RED indicator flashes two times per second during 121.5 MHz/243 MHz transmission and one long flash during

406 MHz transmission.

The buzzer sounds two beeps per second during 121.5 MHz /243 MHz transmission and is silent during 406 MHz

transmission.

When the ELT is tested:

The RED indicator comes once at the beginning and after three seconds for a 3 second duration.

Short pulses indicate test failure.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

14

CONTROLS AND INDICATIONS ON RCP

The ON-ARMED-TEST/RESET switch:

Is set to the ARMED position for automatic operation of the ELT. The switch is kept in the ARMED position by a stop,

which is part of the switch assembly.

Is set to the ON position for manual operation of the ELT. You must pull the switch to clear the stop, and then set it to

the ON position.

Is set to the TEST/RESET position to stop accidental operation, or to do a BITE test. The switch goes back

automatically to the ARMED position after you have set it to

the TEST/RESET position.

The ON/TEST indicator comes on when the ELT operates, or to

indicate the BITE test result. When the ELT operates the ON/TEST

indicator:

Flashes two times per second during 121.5 MHz - 243 MHz transmission

And, one long flash during 406 MHz transmission.

Note: During testing, the ground horn sounds and on 108 VU panel, ELT indicator light (113MX) illuminates.


TRANSMITTER (ELT)

REVISION 1 MAY 2008

15

3. A320 FAMILY PORTABLE ELT

(Refer supplementary notes)


TRANSMITTER (ELT)

REVISION 1 MAY 2008

16

REVIEW QUESTIONS

1. COSPAS-SARSAT satellites can receive:

(a) 121.5 MHz and 243 MHz signals

(b) 406 MHz signals

(c) Both (a) and (b)

2. If an on-board ELT is accidentally activated for 40 seconds before it is noticed and turned off,

(a) 121.5 MHz and 243 MHz signals have been transmitted

(b) 406 MHz signals have been transmitted

(c) Both (a) and (b)

3. What CANNOT you do on the Remote control Panel (RCP) in

the cockpit?

(a) Activation of transmission

(b) Test

(c) Programming aircraft identification

4. During testing, a series of short red flashes indicates

(a) Test fail

(b) Test Pass

(c) 406 MHz transmission

REFERENCES

For further information, read:

www.cospas-sarsat.org

AMM Chapter 25-65

CANNAD 406 technical documentation

A320 Emergency Location Transmitter

Documents

Transcript of A320 Emergency Location Transmitter