Altimeter

TB 9-4920-363-24

airspeed, absolute pressure) are approached in an increasing

direction. In addition, the operator can see if excessive friction

has developed in instruments. This exercise will also reduce

friction on subsequent test runs. Any leaks detected during

this exercise must be corrected before continuing.

CAUTION

If relief valves open for any reason during a test on any

instrument, test must be halted and readings on all

instruments returned to normal before proceeding with test. If

a relief valve opens before highest indication is reached,

corrective maintenance is required.

g. Review each TI calibration chart and insure that a chart is available for each TI

meter. If a correction chart is incorrect or missing, a new correction chart must be made

and attached to the TI. The correction chart will show standard indications when the TI

indicates nominal values.

8. Altimeter

a. Performance Check

(1) Connect pneumatic pressure standard 17 PSIA inlet port to TI RATE OF

CLIMB altimeter connector, using hose assembly supplied with TI.

(2) Set controls on pneumatic pressure standard to indicate altitude in feet.

NOTE

TI VACUUM UP and DOWN control valves must be open

when operating pressure side. PRESSURE UP and DOWN

valves must be open when operating vacuum sides.

(3) Position TI controls as listed in (a) through (f) below:

(a) ALTIMETER case control valve to OPEN.

(b) VACUUM selector control valve to OFF.

(d) VACUUM INCREASE and DECREASE control valves to open position.

(e) PRESSURE INCREASE and DECREASE control valves to closed position.

(f) POWER switch to ON.