This test determines the magnetic effect of the equipment and is mainly intended for finding or proving the closest distance to compasses or compass sensors (flux gates) at which that unit is allowed to be installed.
This test ensures that equipment can operate properly without interference which may affect the nearby equipment, determining equipment compliance with the applicable equipment performance standard or assisting the installer in choosing the proper location of the equipment in the aircraft.
Test Description
The magnetic effect of the equipment shall be determined in terms of the equivalent deflection of a free magnet in a uniform magnetic field (as produced by the earth) having a horizontal intensity of 14.4 A/m ±10% when the equipment under test is positioned on the east-west line through the pivot of a magnet.
This measurement may be performed with either an uncompensated compass or an equivalent magnetic sensor.
Category Y: D = 0.0 m. The deflection of the compass is ≤1˚ when measured immediately adjacent to the equipment. This category should be used for equipment whose installation is placed between 0.0 m and 0.3 m from the magnetic compasses or flux gates.
Category Z: 0< D ≤ 0.3 m. The deflection of the compass is equal to 1˚ when measured >0.0 m to ≤0.3 m to the equipment. This category should be used for equipment whose installation is ≥ 0.3m to magnetic compasses or flux gates.
Category A: 0.3< D ≤ 1 m. The deflection of the compass is equal to 1˚ when measured >0.3 m to ≤1.0 m to the equipment. This category should be used for equipment whose installation is ≥ 1 m to magnetic compasses or flux gates.
Category B: 1 m < D ≤ 3 m The deflection of the compass is equal to 1˚ when measured >1.0 m to ≤3.0 m to the equipment. This category should be used for equipment whose installation is ≥3 m to magnetic compasses or flux gates.
Category C: The deflection of the compass is equal to 1˚ when measured >3.0 m to the equipment. This category should be used for equipment whose installation is >3 m to magnetic compasses or flux gates. Minimum distance for deviation of 1˚ shall be reported in the test form; the equipment location on board will be selected accordingly.
