Home' RTCA Documents for Review : DO-204B, MOPS Aircraft ELT 406MHZ Contents © EUROCAE, 2018
At the completion of the test, it shall be demonstrated that all mechanical devices
operate satisfactorily (ELT(AP) and (S) only). The ELT system meets the
specifications of the aliveness test.
Fire , ELT (Optional, except for ELT(AD) in ADFR)
(including antenna(s) and antenna cabling)
Depending on the type of battery provided with the ELT, the possibility of
explosion makes this test potentially hazardous. Appropriate precautions
should be taken.
The ELT system components shall be subjected to a fire of at least 1100°C,
producing a minimum thermal flux of 15.8 Watts/cm2 (50 000 BTU/ft2 hr).
The minimum diameter of the area of the fire shall be twice the maximum diagonal
dimension of the ELT system components,
The flames shall envelope the outside area of the ELT system components for a
continuous and uninterrupted period of at least two minutes.
After removal from the flame, the ELT system components shall be allowed to cool
naturally to ambient temperature before being tested. The ELT system shall meet the
At the completion of the test, ensure that all mechanical devices operate satisfactorily.
Post-crash Immersion (Optional for ELT(AF) and ELT(DT)) (SPECIAL)
The ELT unit shall be activated then immersed in a salt solution, conforming to the
ED-14G/DO-160G, § 14.3.4, for a period of 1 hour. The temperature of the solution
shall be between +30°C and +40°C.
The ELT unit shall be immersed to a depth such that all parts of the ELT unit are more
than one meter below the surface of the solution.
At the end of the one-hour period, the ELT shall be removed from the solution.
After subjecting the ELT system to this test,
the ELT unit shall have remained activated,
the ELT unit shall comply with the specifications of the aliveness test,
and ensure that all mechanical devices operate satisfactorily.
Buoyancy (ELT(AD), (AP), (S) Category A)
The equipment shall satisfy the specifications of the following paragraphs:
With the ELT antenna deployed in its normal operating position, the ELT unit shall,
when rotated to a horizontal position about any axis, be submerged in fresh water just
below the surface, and when released the ELT antenna shall pass through an upright
position within 2 s.
In the case of an ELT(AD) not in ADFR, the ELT unit shall be submerged at the design
deployment induced by immersion depth or equivalent pressure for 5 mn.
In calm fresh water, the ELT unit shall float upright with the antenna within 20 degrees
Fresh water is defined as normal domestic tap water.
The reserve buoyancy of the ELT unit and its antenna shall be at least 5 % in fresh
water when determined by one of the following methods:
a) the complete unit shall be submerged and the buoyant force shall be measured
with a scale. The buoyant force shall be divided by the weight of the unit. The
result shall be at least 1.05;
b) the location of the water-line shall be determined on the floating ELT unit. The
calculated or measured volume of the unit above the water-level shall be
divided by the calculated or measured volume below the water-level. The result
shall be at least 0.05.
Perform an aliveness test
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