TEST CHAMBER ASSEMBLY, MODEL 452 OPERATION UNDER USUAL CONDITIONS

TM 10-1670-305-23&P TEST CHAMBER ASSEMBLY, MODEL 452 0009 00 OPERATION UNDER USUAL CONDITIONS OPERATING PROCEDURE NOTE 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) to COCK. CAUTION Climb rates or fall rates greater than 833 ft/sec may cause damage to the altimeter. NOTE 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. CAUTION 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. NOTE 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. NOTE 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. 0009 00-7 Change 1