TEST CHAMBER ASSEMBLY, MODEL 452
OPERATION UNDER USUAL CONDITIONS
The end of the AR2 piston rod will be visible when the AR2 is cocked.
6. Move the CLIMB/FALL/COCK switch (8) on test chamber to COCK for two seconds. Since
the AR2 is already cocked, nothing will happen. On subsequent tests, after actuating the test
unit, it will be necessary to recock the test unit by moving the CLIMB/FALL/COCK switch (8)
Climb rates or fall rates greater than 833 ft/sec may cause damage to the
When conducting tests with AR2 dial settings greater than 15,000 feet, increase
the wait time from 30 or more seconds to 40 or more seconds once the desired
altitude is reached. Inadequate wait time can result in erroneous test results.
7. Move the CLIMB/FALL/COCK switch (8) on test chamber to CLIMB position. Adjust the
pressure control regulator (14) on the test chamber to the desired altitude as observed on the
altimeter (4). This altitude should be at least 2,000 feet above the altitude set on the altitude
dial (refer to step 3). Once the desired altitude is reached, wait 30 or more seconds for the
unit to stabilize. This allows pressure trapped in the rate-of-fall sensing chamber of the AR2
to bleed off so that it comes to the same pressure as the surrounding environment. This will
allow the rate of fall mechanism to function properly.
Do not select a rate of fall between 65 and 85 ft/sec. Repeated testing between
these values will cause excessive wear to the rate-of-fall mechanism of the AR2
and result in malfunctions.
The barometric pressure adjustment setting on the altimeter on the test chamber
shall always remain at 29.92 to assure correct readings of altitude with respect to
mean sea level.
Values shown on FUNCTIONS decal on test chamber correspond approximately
to rates of fall indicated thereon. The exact rate of fall during testing should
always be determined with the aid of a stop watch.
8. Turn the PRESSURE CONTROL regulator (10) on the test chamber console to adjust the
rate of pressure increase inside the altitude test chamber. Adjust pressure as observed on
the pressure (PSI) gage (11) of the test chamber to a pressure corresponding to a rate of fall
of 85 to 90 ft/sec. The rate of fall should be established between 6,000 and 5,000 feet.