Home' RTCA Documents for Review : DO-204B, MOPS Aircraft ELT 406MHZ Contents © EUROCAE, 2018
b. Fire Test (Optional).
Grouping of Tests
Two groups of tests are specified: A and B. These groups are intended to represent
the environmental situations likely to be experienced by an ELT system, and the order
in which they will occur.
The ELT(DT) system without crash survivability capability do not have to withstand the
crash conditions, but need however to operate without adverse effect on the aircraft
operation, and to withstand the normal flight conditions as well as to operate in the
degraded environmental conditions experienced between the detection of the distress
condition and the crash. As a result, the tests for the ELT(DT) system without crash
survivability capability are detailed in TABLE 4-5.
The tests for the ELT(DT) system with crash survivability capability are detailed in
TABLE 4-1, except for the crash sensor test when not implemented.
When ELT(DT) is referred to in the tests description (§ 4.4 and § 4.5), this
refers to ELT(DT) with crash survivability capability.
The groups of tests are as follows.
18.104.22.168 Group A
Low Temperature (Activation), High Temperature (Activation), Altitude,
Decompression, Overpressure, Magnetic Effect, Power Input, Voltage Spike
Conducted, Audio Frequency Conducted Susceptibility, Induced Signal Susceptibility,
Radio Frequency Susceptibility, Lightning Induced Transient Susceptibility, Lightning
Direct Effects, Emission of Radio Frequency Energy, Explosion Proofness, Icing,
Flammability, Triboelectric effects.
22.214.171.124 Group B
Electrostatic Discharge, Humidity, Waterproofness, Fluids Susceptibility, Fungus
Resistance, Sand and Dust, Salt Spray, Vibration, Shock, Impact, Crush, Flame, Fire,
Post-Crash Immersion, Buoyancy, Frequency Stability with temperature gradient.
4.3 TEST PROCEDURES AND METHODS (EXCEPT ELT(DT) WITHOUT CRASH
Unless otherwise specified the temperatures quoted in this document have a tolerance
of +/-3° C. When the term "allowed to stabilise" is used, it means that the ELT system
shall have been exposed to the appropriate temperature for at least 2 hours.
To ensure satisfaction of the specifications of § 4.2.4, an ELT unit or ELT system
designed to this Minimum Operational Performance Specification shall be subjected to
the required sequence of environmental tests and conditions specified in this chapter.
The following test procedures will specify whether they are to be applied to the ELT
unit, the complete ELT system, or individual ELT system components.
Where tests require either the performance of the ELT system to be verified or the
aliveness test to be carried out then the antenna should be disconnected from the ELT
unit and the measurement equipment connected to the ELT unit output instead.
Antenna performance, where required to be verified, is always achieved by performing
a VSWR test before, during or after the test.
For each environmental test, whether the procedure to be used is the standard
procedure from EUROCAE ED-14G/RTCA DO-160G or a custom procedure as
described below, the “applicable equipment performance standards” are listed. An
aliveness test measuring the nominal carrier frequency and the RF output power of
the unit under test shall be performed as designated in the test specification. When
performing the aliveness test, the carrier frequency measurement may be made on a
single burst of the total 406 MHz transmission. The aliveness test is comprised of the
the nominal 406 MHz carrier frequency § 3.7
b. the 406 MHz RF output power § 3.7
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