Boeing B737 - User Manual

B737
MAINTENANCE MANUAL
EFFECTIVITY
Post ELT STC ST03081AT
23-24-00
PAGE 001
JAN 02/07
EMERGENCY LOCATOR TRANSMITTER SYSTEM
DESCRIPTION AND OPERATION
1. General
A.
The ARTEX C406-1 series ELT’s are a “third generation ELT,” transmitting on 121.5, 243.0 and
406.025 MHz. The ELT’s are designed to meet or exceed the requirements of TSO C91a, TSO
C126 and the mandatory automatic ELT requirements of FAR Part 91. The ELT meets the
requirements of Canadian Aviation Regulation (CAR) Part V, Subpart 51, Airworthiness Manual
Section 551.104. In addition, these ELT’s are designed to meet the requirements of Eurocae ED-
62.
B.
The C406-1 series ELT’s employ a completely new transmitter which features higher output
power and a more integrated design. The 121.5/243.0 MHz section of the transmitter is
contained in a module with the 406.025 MHz transmitter. The top circuit board contains the
microprocessor that controls the module and all ELT functions. The C406-1 is a single output
ELT, unlike previous models of ARTEX 406 MHz ELT’s.
C.
The ELT automatically activates during a crash and transmits the standard swept tone on 121.5
and 243.0 MHz. Every 50 seconds for 520 milliseconds (long message protocol) the 406.025
MHz transmitter turns on. During that time an encoded digital message is sent to the satellite.
The information contained in that message is shown below:
• Serial Number of the Transmitter or Aircraft ID
• Country Code
• I.D. Code
• Position Coordinates (when coupled to an ARTEX ELT/NAV Interface unit [453-6500]).
D.
The 406.025 MHz transmitter will operate for 24 hours and then shuts down automatically. The
121.5/243.0 MHz transmitter will continue to operate until the unit has exhausted the battery
power which typically will be at least 72 hours.
E.
The ELT/NAV Interface unit (if installed) allows the ELT to communicate with the aircraft’s
navigation system and receive position data (longitudinal and latitude) which the ELT will transmit
in the event of a crash. Programming the ELT with the 24 bit long message protocol allows the
ELT to be automatically programmed by the ELT/NAV interface with the aircraft’s 24 bit address.
The ELT/NAV interface unit must be strapped (binary “1” bits tied to ground) with the same 24 bit
address as the ICAO or mode S transponder system 24 bit address. This gives the ELT the
ability to be moved from one aircraft to another without the need for manual reprogramming of
the ELT. This is advantageous for fleet operators since the ELT/NAV interface unit will
automatically reprogram the ELT with the new aircraft’s 24 bit address identification.
F.
The ARTEX DGL-a dongle allows the operator to easily program aircraft 24-bit (Long Message
Protocol) address into a compatible ELT. The DGL-1 comes attached to the top cover. The top
cover and dongle remain with the aircraft. When an ELT is installed, the DGL-1 reprograms the
ELT with the aircraft’s 24 bit address. The operation of the dongle is fully automatic. When
aircraft power is applied, the DGL-1 verifies the ELT is programmed to the 24 bit address stored
in the dongle. If the addresses match, the DGL-1 shuts down. If there is no match, the DGL-1
reprograms the ELT to the 24 bit address stored in the dongle and then shuts down.

Summary

1. General - Description and Operation

ARTEX C406-1 ELT Overview

General description of the third-generation ELT, its purpose, and standards met.

C406-1 Transmitter Design

Description of the integrated transmitter, microprocessor, and single output design.

ELT Activation and Data Transmission

Details on automatic activation, swept tone, and 406 MHz digital message protocol.

Position Data Integration

How position coordinates are transmitted via ELT/NAV interface.

ELT;NAV Interface Unit Functionality

How the interface unit communicates navigation data and enables automatic reprogramming.

Programming Dongle Functionality

How the dongle programs the ELT with the aircraft's 24-bit address.

406.025 MHz Accuracy and Data

Advantages of 406.025 MHz accuracy and information contained in the satellite database.

Homing and Monitoring ELT Signals

Use of 121.5/243.0 MHz for homing and cockpit monitoring of ELT signals.

Cockpit Controls and Limitations

Description of cockpit switch functions and operational limitations.

ELT Housing and Environmental Resistance

Details on the ELT's durable case and operating temperature range.

2. Component Details

ELT Transmitter Components

Description of the ELT transmitter's PCA, RF module, modulation, power, sensor, and battery pack.

Programming Dongle (DGL-1)

Details on the ARTEX DGL-1 dongle for programming the 24-bit address.

Remote Control Functionality

Description of the remote control panel switch modes and wiring design.

3. Operation

Automatic and Manual Activation

Covers automatic crash activation and manual activation via cockpit switch.

ELT State Management and Reset

Explains active/inactive states, transition sources, and reset procedures.

Operational Checks and Limitations

Discusses periodicity of checks and reset limitations.

1. General - Fault Isolation

Pre-Test Maintenance Practices

Emphasizes applicable maintenance practice before proceeding with testing.

2. System Tests

ELT System Functionality Test

Describes the operational test for basic ELT functionality.

3. Fault Isolation

Microprocessor Fault Detection

How the microprocessor checks G-switch, transmitter, and navigation data.

LED Fault Code Indicators

Explains LED flash codes for various detected problems.

Sequential Fault Reporting

How faults are reported in sequence based on detection order.

ELT;NAV Interface Error Conditions

Describes rapid LED flashing for interface communication issues.

1. General - Maintenance Practice

Regulatory Compliance and Inspection

Procedures to comply with FAA/Canadian regulations and required 12-month inspection items.

Recommended Monthly Self-Test

Importance and recommended frequency for performing a monthly ELT self-test.

ELT Removal Procedure

Step-by-step guide for removing the ELT transmitter from its mounting tray.

2. Battery Pack Replacement

Battery Pack Procedures

Detailed procedures for removing, replacing, and reinstalling the ELT battery pack.

3. ELT System Testing and Verification

System Functionality Test

Operational test to verify basic ELT system functionality and performance.

Fault Diagnosis and LED Indicators

Interpreting LED flash codes and understanding fault isolation during testing.

Power Output and Frequency Tests

Procedures for testing ELT power output on various frequencies and frequency accuracy.

Digital Message and Protocol Verification

Verifying the integrity and content of the digital message transmitted by the ELT.

SARSAT Beacon Tester Operation

Guidelines for using the SARSAT Beacon Tester for ELT verification.

1. General - Removal and Installation

Scope and Safety Precautions

Overview of the section and critical safety precautions for installation and removal.

2. Equipment and Materials

Required Tools and Supplies

List of common shop equipment and materials needed for ELT installation.

3. ELT Transmitter Removal and Installation

ELT Transmitter Removal Procedure

Step-by-step instructions for safely removing the ELT transmitter unit.

ELT Transmitter Installation Procedure

Detailed steps for correctly installing the ELT transmitter into the aircraft.

4. ELT Antenna Removal and Installation

ELT Antenna Removal Procedure

Instructions for removing the ELT antenna from the aircraft fuselage.

ELT Antenna Installation Procedure

Steps for properly installing the ELT antenna, including sealant application.

5. Remote Switch Removal and Installation

Remote Switch Removal Procedure

Instructions for removing the remote switch from its aircraft mounting location.

Remote Switch Installation Procedure

Steps for reinstalling the remote switch into its mounting location.

1. General - Adjustment & Test

Purpose of Adjustment and Test Procedures

Overview of procedures for periodic testing and adjustment of the ELT system.

2. ELT Operation Tests

System Test Procedure

Detailed steps for performing the operational system test of the ELT.

Boeing B737 Specifications

General

Brand	Boeing
Model	B737
Category	Transmitter
Language	English