Mode C (Altitude) Tests

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T M 11-5895490-20

e. Mode C (Altitude) Tests. Mode C tests

( 3 ) Obtain the local barometric altitude

are performed with the RT-859/APX72 con-

from the operations group and refer

nected to an auxiliary Pressure Altitude Digi-

to the chart below for the AN/APM-

tizer CPU-66/A, or equivalent.

123A (V) code control settings to be

used, Preset this code in the AN/

(1) Set the AN/APM-123A (V) MODE

APM-123A(V).

switch to C and FUNCTION switch

to SYSTEM.

Note: The chart provides altitudes in increments of

(2) Set the C-6280 (P)/APX M-C switch

100-foot values. The code settings shown for each value

should be used for altitudes 50 feet below and above

to ON and all other mode switches to

that shown. For example, when the local barometric

OUT.

altitude is between 50 and 150 feet, use 100 feet, etc.

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