(b)
Apply the water to the pneumatic duct boot seal and the system penetrations between the 306 strut to wing vapor barrier and the NSTA 241 bulkhead.
(c)
Apply 254 to 258 fluid ounces (7510 to 7630 ml) of water in 3.5 to 4.5 minutes.
NOTE: This is approximately 64 fluid ounces (1/2 gallon or
____ 1900 ml) per minute for 4 minutes.
1) Make sure that all surfaces receive the same amount of water. 2) Do not apply water to the strut to wing sponge seal.
S 792-265
(3) Make sure there is no water leakage through the midspar into the dry bay area.
(a) Leakage from the left and right dry bay drain tubes into the dry bay is not permitted.
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(4) S 792-266Make sure there is no leakage through the strut to wing vapor barrier wire bundle and tubing penetrations or through the strut to wing vapor barrier.
NOTE:____ Use the aft fairing panels 462QL/472QL for access.
(5) S 792-267After three minutes, make sure that a minimum of 236 fluid ounces (6980 ml) of water has collected in the container.
(6) S 792-268Make sure there is no puddling of water in the strut area.
NOTE:____ Puddling is defined as more than 0.5 fluid ounce (15 ml) of water in a continuous pool.
(7) S 792-269Look for gaps at the strut to wing sponge seal as follows: (a) Put a bright shop light into the strut, a small distance aft of the strut to wing vapor barrier at NSTA 363. (b) Use the upper wing leading edge cover for access to view the strut to wing sponge seal. (c) Make sure there are no gaps between the sponge seal and the structure.
NOTE:____ Light will show through gaps.
(8) S 392-270If you found water leaks during the test, do these steps: (a) If the leak is from a tube, do the procedure to repair the tube (AMM 20-11-05/801). (b) If the leak is from a seal, do the procedure to seal the applicable area of the leak (AMM 51-31-01/201). (c) After you repair the leak, do the applicable leak test again.
(9) S 362-271If you did not collect the correct amount of water and cannot find leaks, do these steps: (a) Do the task to clear the applicable strut drain.
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747-400 MAINTENANCE MANUAL
(b)
If you cannot remove the blockage with air, use a thin wire to clear the applicable drain tube.
(c)
Continue to remove the blockage in the tube and do the leak test again until you collect the correct amount of water.
G. If you will not do more leak checks at this time, put the airplane back to its usual condition.
S 162-272
CAUTION:_______MAKE SURE YOU KEEP THE STRUT AREA CLEAN. TOOLS, LOOSE AND UNWANTED MATERIALS IN THE STRUT COMPARTMENTS CAN BLOCK THE REMOVAL OF THE FLUIDS THROUGH THE STRUT DRAINS. IF YOU DO NOT REMOVE THE UNWANTED MATERIALS, YOU CAN CAUSE DAMAGE TO THE STRUT.
(1)
Make sure you remove all unwanted materials from the strut cavities.
S 412-273
(2)
Close the upper wing leading edge cover 511CT/611CT.
S 412-274
(3)
Install the dry bay access panels 462FL/472FL and 462GL/472GL.
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