(2)
Tests should be run with drain caps connected to drain fittings.
NOTE: To test poppet valves in drains, run test with drain caps off drain fittings. Leakage test must then be rerun with drain caps connected.
(3)
Pitot static probe heaters are to remain off during this test.
(4)
Open FLAP LOAD RELIEF circuit breaker on P6 panel.
WARNING: FAILURE TO OPEN TE FLAP LOAD RELIEF CIRCUIT BREAKER MAY RESULT IN FLAP MOVEMENT AND INJURY TO PERSONNEL.
(5)
Connect test equipment (Fig. 501) as follows:
(a)
Connect static probe adapters and cutoff valves to those static systems to be tested. Connect an external altimeter or pressure indicator between static cutoff valve and airplane system.
(b)
Connect static control valve between cutoff valves and static test unit.
(c)
Connect pitot probe adapters and cutoff valves to those pitot systems to be tested. Connect an external airspeed indicator or pressure indicator between the appropriate cutoff valve and the airplane system.
(d)
Connect pitot control valve between cutoff valves and pitot test unit.
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Feb 20/89 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 34-11-01 Page 503
D. Test Pitot Systems
(1) Test captain's pitot system for leakage, observing the cautions in steps A.(3) and A.(4) above.
NOTE: Accuracy of reading and recording pressure should be士 0.03 inches of mercury or士 1 knot.
(a)
Temporarily seal pressure chamber drain hole in captain's pitot static probe (upper left probe). Connect air pressure supply to pitot static probe (pitot pressure portion).
(b)
For low-range leakage test: 1) Apply pressure of 250 knots on captain's airspeed/mach indicator or test indicator.
2) After system has stabilized, cut off pressure between airplane system and pressure source. Read and record airspeed/mach indicator or test indicator reading.
3) Wait 1 minute. Check that pressure does not decrease more than 2.5 knots.
(c) For full-range leakage test:
1) Apply pressure of 4.53 (士 0.16) inches of mercury (gage) or 300 (士 5) knots on captain's airspeed/mach indicator or pressure indicator. 2) After system has stabilized, cut off pressure between airplane system and pressure source. Read and record airspeed/mach indicator or test indicator.
3) Wait 1 minute. Pressure should not decrease more than 0.16 inches of mercury or 5 knots of airspeed.
(2)
Test first officer's pitot system for leakage.
(a) Repeat steps D.(1)(a) through (c) above on the upper right pitot static probe.
(3)
Test auxiliary No. 1 or No. 2 pitot system for leakage.
(a) Repeat steps D.(1)(a) through (c) on lower right probe (No. 1 system) or lower left probe (No. 2 system).
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34-11-01 Page 504 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Feb 20/89
E. Test Static Systems
(1) Temporarily seal all static ports to which test adapters have not been applied. Method of sealing should not extend into static ports or deform or alter surface in the area when seals are removed.
CAUTION: PITOT PRESSURE SHOULD ALWAYS EQUAL OR EXCEED STATIC LINE PRESSURE AND DIFFERENCE (DIFFERENTIAL PRESSURE) SHOULD NOT EXCEED 10.00 INCHES OF MERCURY. DIFFERENTIAL PRESSURE DESCRIBED ABOVE SHOULD NOT FALL BELOW ZERO.
NOTE: Accuracy of reading and recording vacuum pressure or altimeter should be 士0.01 inches of mercury or士20 feet of altitude respectively.
(2) Test captain's static system for leakage observing cautions in steps A.(3) thru A.(6).
(a)
Place all static cutoff valves in open position.
(b)
Apply a vacuum to captain's static system on lower right probe (preferred) or drain fitting No. 2 (connection not shown in Fig. 501).
(c)
For low-range leakage test: 1) Apply a vacuum to the system, so that captain's altimeter indicates an altitude of 3000 feet. 2) After system has stabilized, shut off vacuum using appropriate static cutoff
valve. Read and record altimeter or test indicator reading. 3) Wait 1 minute. Check that vacuum does not decrease more than 60 feet.
(d)
For full-range leakage test:
1) Apply a vacuum equivalent to 12.37 士0.10 inches of mercury (absolute pressure) so that captain's altimeter indicates 22,500士200 feet. Pitot system should also be evacuated, if necessary, to meet the requirement under the caution note.
2) After system has stabilized, shut off vacuum using appropriate static cutoff valve. Read and record altimeter or pressure indicator reading. 3) Wait 1 minute. Vacuum should not decrease more than 0.21 inches of mercury or 400 feet in altitude.
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