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Water Safety Relief Manometer 574
28-11-0 Figure 105 Nov 15/78
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(4) Establish internal leak source using one of the methods described in preceding text.
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M. Hollow Bolt Methods for Use in Areas of Structural Buildup
(1) Hollow Bolt -Air Bubble Method. (Try this method prior to Hollow Bolt Dye Injection Method.)
(a)
Prepare tank for entry per Fuel Storage System 28-10-0 MP.
(b)
Remove a good fastener and install hollow bolt fastener in fastener hole (Fig. 107). All removal and installations to be in accordance with Structural Repair Manual.
(c)
With air bleed hose clamp closed, connect regulated air pressure supply. The air supply should come either through a F71329 leakage tracing device or have a safety relief manometer fitted into the system.
(d)
Apply soap solution to suspected leak area inside tank.
(e)
Apply 4 psi air pressure.
CAUTION: MONITOR EQUIPMENT AT ALL TIMES TO ENSURE THAT 4 PSI PRESSURE IS NOT EXCEEDED.
(f)
Mark leak points inside tank and remove all evidence of soap solution. If results are not obtained within approximately 20 minutes, try hollow bolt dye injection method.
Leak Detection in Areas of Structural Buildup 574
28-11-0 Figure 106 May 01/01
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N. Hollow Bolt Dye Injection Method
(1)
If leakage tracing device F71329 was used in preceding test, follow instructions on box cover for applying dye and air pressure to bolt. If substitute equipment was used, proceed as required to obtain desired results.
(2)
Suggested dyes are:
(a)
Intense green or bluish-white fluorescent dye solution to be used with an ultra-violet light. Use 1 ounce of either color to 1 gallon of fuel.
(b)
If an ultra-violet light is not used, use red nonfluorescent dye in concentrations of up to 2 fluid ounces per 100 gallons of fuel.
(3)
When dye appears in tank, mark point of penetration.
O. Locating Equipment or Fitting Leaks -Talcum Powder Method
(1) This procedure deals only with determining whether or not leak is caused by equipment or fitting leaks at tank boundaries. If equipment or fittings are not leak source, it must come from a compound sealed or fastener sealed origin. Proceed as follows:
(a)
Have talcum powder and a thick bristled camel hair brush for dusting powder on suspected leak source available. Also plenty of clean dry cotton cloths.
(b)
Wipe up leak area thoroughly with absorbent cotton cloths.
(c)
Wipe connection thoroughly using three or four changes of cloth in process. It must be completely dry.
(d)
Immediately dust connection with talcum powder.
(e)
First trace of fuel touching talcum will cause it to change color. Consequently, area must be kept under constant watch.
(f)
If no change is immediately apparent in talcum, wipe surrounding area that was previously wiped dry and dust talcum over entire area.
(g)
Observe dusted area closely for first signs of color change in talcum.
(h)
If talcum changes color at connection, leak has been isolated. See applicable section for removal and installation of component.
(i)
If fuel discolors talcum at another location, for instance at lockbolt or rivet installation, there is a possibility of it being a contributor to the leak also. Leaks in bottom of wing around access doors can usually be attributed to a faulty O-ring in access door.
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P. Wing Dry Bay Pressurization Method
(1)
Defuel and purge fuel tank having dry bay with fuel leak (Ref 28-23-0 MP, 28-10-0 MP).
(2)
Remove fuel tank access panels 7202, 7204, 7205, and 7206 (left side) or 7402, 7404, 7405, and 7406 (right side), as applicable (Ref 28-11-11 R/I).
