A.  Corrosion should be removed by one of the methods described in 20-60-00.

B.  Restore damaged finish after corrosion removal in accordance with 20-60-00.

Volume 1

20-62-00
Page 3
OCT 01/02

CORROSION PREVENTION MANUAL
STANDARD PREVENTIVE MAINTENANCE METHODS
MICROBIAL GROWTH IN INTEGRAL FUEL TANKS

5.  Biocide Treatment

A. If you put a biocide into the fuel storage tanks, to the tanker supplying

the airplane, or directly into the airplane tanks, you will reduce the inci-dence of microbial growth. We recommend two options, Biobor JF (Hammond
Technical Services, Inc., V47186) or Kathon FP 1.5 (Fuel Quality Service,
Inc., V40161).

NOTE:  Specific recommended instructions for the use of Kathon FP 1.5 will be
added as required; however, suggested application time periods in step

C. and residual water drainage described in step E. should be adhered to
in addition to restrictions shown in the following table:

KATHON FP 1.5 BIOCIDE

CONTINUOUS USAGE INTERMITTENT USAGE
Parts per Million Parts per Million
ENGINE MANUFACTURER (by weight) (by weight)

General Electric 100 P.P.M.  100 P.P.M.

Rolls-Royce 50 P.P.M.  100 P.P.M.

CFM  100 P.P.M. 100 P.P.M.

Pratt-Whitney 100 P.P.M.  100 P.P.M.

B.  The quantity of Biobor JF approved by engine manufacturers to treat aviation
fuel is 270 parts per million (ppm) for intermittent applications. This con-centration can be used for initial treatment. Follow-up treatment of 135-150
ppm with application time periods made in conjuction with service checks
that will allow the biocide to remain in the tanks for the period of time
noted in par. F are recommended. Intermittent applications should be made if
fuel analysis indicates fuel contamination with fungus. To calculate the
quantity of biocide required (in fluid ounces) to treat the fuel, multiply
the quantity of fuel in pounds by 0.004. This gives 270 ppm concentration.

(Use half of this for a 135 ppm concentration). This is equivalent to 25.37

fluid ounces of biocide per 1000 gallons of JP4 or 25.86 fluid ounces of
biocide per 1000 gallons of kerosene calculated on a fuel density at 15°C.
Interpolations may be made for other concentrations.

C.  The application time periods will vary for each operator and will depend on
the operating environment (including fuel storage tanks). Operating envi-ronment will determine the amount of moisture and subsequent microbial
infestation present in the fuel tanks. It is recommended that operators in
severe environment make the first follow-up treatment one month after the
initial control treatment. Subsequent biocide concentrations and applica-tion time periods may be adjusted after fuel sample analysis of fuel drained
from the airplane tank indicate the degree of fuel contamination.
　
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