01 March 2005
and 30% distilled water, both by volume, and put into
where the indicating solution has changed color. Ensure
a plastic spray bottle with a hand squeeze pump. Add
that the area is well saturated and that the stream is
one tablespoon of litmus powder into the liquid, and
directed into all seams and crevices where electrolyte
mix thoroughly until a deep blue color is observed.
could collect. Use care to prevent liquids from spreading
to adjacent areas, and ensure that bilge area drains
also be used as an indicator.
are open to allow fluids to flow overboard. Allow the
neutralizing solution to remain on the surface for at
6-184.108.40.206. Bromothymol Blue Indicating Solution.
least 5 minutes or until all bubbling action ceases.
Bromothymol blue indicating solutions are used on
nickel-cadmium battery electrolyte spills. To prepare
d. Rinse the area thoroughly with a liberal amount
solution, mix 14 teaspoon of Indicator, Bromothymol
of clean water and remove any standing liquid or
Blue Reagent (Volume IV or V, Chapter 2) in 3 cups
puddles, as in paragraph a.
(24 oz.) of deionized or distilled water. Pour one pint of
bromothymol blue solution into a plastic spray bottle
e. Reapply the indicator solution, as in paragraph b.
with a hand squeeze pump. Using an eye dropper, add
If the solution does not change color, rinse the area, as
one drop at a time of phosphoric acid, A-A-59282,
in paragraph d., and dry the area with clean cloths or
rags. If the solution changes color, repeat paragraphs c.
after adding each drop, until the color of the solution
changes from blue to gold/amber.
f. Repair damage and apply prepaint treatment,
6-220.127.116.11. Sodium Bicarbonate Neutralizing Solution.
sealant, and coatings as required. Special acid and/or
Pour one pint of fresh water into a wash bottle, add two
alkali resistant coatings are usually required for battery
ounces (4 tablespoons) of Sodium Bicarbonate, ASTM
compartments, boxes, and areas. Refer to the
D 928 (Volume IV or V, Chapter 2) and mix thoroughly.
applicable aircraft manuals.
6-18.104.22.168. Boric Acid Neutralizing Solution. Pour one
6-2.5. FRAMES, MOUNTING RACKS, AND SHOCK
pint of fresh water into a wash bottle, add one-half
MOUNTS. Shock mounts and associated hardware on
ounce (I tablespoon) of Boric Acid, A-A-59282
pod/airframe mounted equipment are usually the last
items to be inspected for corrosion damage. This is
usually because inspection requires the removal of the
6-2.4.2. Cleaning and Neutralizing Procedures.
shock mount to facilitate examination. For this reason,
shock mounts and associated metallic hardware must
a. Remove any standing liquid or puddles with a
be preserved to ensure protection. This does not
squeeze bulb type syringe, absorbent cloth, or sponges.
eliminate the requirement to inspect shock mounts.
Place these items in a leak-proof container for removal
For frames, mounting racks, and shock mounts that
are not normally painted, remove corrosion and
preserve as follows:
b. Spray the entire suspected area with the proper
indicator solution, using the minimum amount needed
to wet the entire surface. For spills from lead acid
batteries, use the litmus solution, which will change in
The use of dissimilar metals in the selection of
color from deep blue to a bright red in areas
s c r e w s , washers, and nuts should be
contaminated by sulfuric acid. For spills from
eliminated, wherever possible. Refer to
nickel-cadmium batteries, use the bromothymol blue
solution, which will change in color from amber or gold
to a deep blue in areas contaminated by potassium
a. Remove corrosion with Abrasive Cloth, 320 Grit,
ANSI-B74.18 Type I Class I (Volume IV or V,
c. Apply the correct neutralizing solution (sodium
bicarbonate solution for lead acid batteries, boric acid
solution for nickel-cadmium batteries) to the areas
to dissimilar metal couples.