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.
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.
(c) PRESSURE selector control valve to NET ALT.
(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.
