contamination, it only provides a qualitative estimate of the relative
amount of contamination.
C. If you find microbial contamination when you do a check of the fuel-water
interface following tank slumping, you should make a tank entry as soon as
possible. If you wait too long to remove microbial growth, you expose the
tank structure and components to a higher probability of corrosion.
D. Entry into contaminated tanks will reveal a colored deposit on the horizon-tal tank surfaces and top surfaces of plumbing. This deposit is usually
brown or black although other colors have been noted. There may also be evi-dence of corrosion products where the effects of microbial contamination are
becoming apparent.
E. Any time the tanks are entered they should be inspected for microbial
growth. Also ensure that limber holes and drains are not blocked. See Volume
2 for location of drains.
Volume 1
20-62-00
Page 2
OCT 01/02
CORROSION PREVENTION MANUAL
STANDARD PREVENTIVE MAINTENANCE METHODS
MICROBIAL GROWTH IN INTEGRAL FUEL TANKS
3. Removal of Microbial Deposits
CAUTION: DO NOT USE DETERGENTS AS THEY SPREAD MICROBIAL GROWTH.
A. Microbial deposits can usually be removed by scrubbing with a soft to firm
brush or sponge and clean warm water.
NOTE: Efficiency of removal is dependent upon how long the tanks are "aired"
prior to removal. The longer they are allowed to dry, the more difficult
the removal.
(1)
Ventilate tanks using air movers. Continue ventilation during tank
cleaning to aid in drying tank.
(2)
Open or remove sump drain valves.
(3)
Starting at the outside edge of the tank, work toward access door open-ings and fuel sump drain.
(4)
Check that tank is free of all loosened fungus.
(5)
Ensure that all drain holes, slots, and tubes are clear of loosened fun-gus or other foreign material which could block drainage of water or
fuel.
B. Mop up residual matter.
C. Thoroughly vacuum clean and flush to remove all remaining foreign material
with the tank following the above cleaning operations.
D. After cleanup of fungus, reworked area may be touched up with Bostik 463-6-28, zinc-rich epoxy primer and topcoated with BMS 10-20.
E. Corrosion removal and restoration of damaged finish is required after
removal of microbial deposits per 20-50-00 and 20-60-00.
4. Removal of Corrosion 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：757 防腐手册 CORROSION PREVENTION MANUAL 第二册 一般信息(66)
