01 March 2005
NAVAIR 01-1A-509-1
TM 1-1500-344-23-1
TO 1-1-689-1
flights involved in anti-submarine warfare (ASW),
the types of fluid intrusion and the possible effects.
moisture is introduced into aircraft via the fine ocean
Some of these fluids are corrosive to metals, while
spray prevalent at lower altitudes. This moisture
others are destructive to seals. The destruction of
saturates wiring harnesses, connectors, antennas,
seals may lead to fluid penetration into areas that are
waveguides, and switches, and causes frequent
considered protected. Some fluids are from external
equipment failure. Flight operations in tropical
sources, while others are present due to internal leaks
environments can produce conditions that support the
or servicing spills.
growth of fungus and other microorganisms.
3-15.9. OPERATIONAL AND MAINTENANCE
ENVIRONMENT. All personnel should familiarize
3-15.9.3. P r o t e c t i o n o f A i r c r a f t D u r i n g G r o u n d
Operations. Equipment can also be damaged during
themselves with their local environment, such as
maintenance periods. Many problems are encountered
moisture, temperature, atmospheric pressure, salt,
while aircraft are parked. In general, the majority of
water, sand, and dust. The type of aircraft, aircraft
aircraft ground time is spent with the aircraft opened up
mission, and ground operations also influence the rate
or unbuttoned. It is often necessary for canopies and
of corrosion.
access panels to be open during certain maintenance
3-15.9.1. Type of Aircraft. Fixed-wing and rotary-wing
functions. This produces situations where moisture,
rain, or ocean spray may soak cockpit and internal
aircraft have some airframe flexibility, which results in
avionic components. Inspection and timely corrosion
seal deterioration. This allows moisture/fluid intrusion.
control is essential for proper operation and full life
Vulnerable areas include gaskets on access doors/
cycle. Maintenance operation time varies widely between
panels; fuselage flexure points; vents, ducts, and static
types of equipment and depends largely on reliability
pressure sensors; equipment bay door and
and troubleshooting time. Most front-line combat aircraft
electromagnetic interference (EMI) gaskets; radome
average 1 to 2 hours per day in flight operations. In
and antenna seals; and opening for steps.
some cases, aircraft may be nonoperational for extended
3-15.9.2. Effects of Aircraft Mission. A number of field
periods while waiting for spare parts. This increases the
corrosion problems are a result of the mission of the
vulnerability of the entire system to corrosion. Some of
aircraft. For example, during a search and rescue (SAR)
the potential problems associated with increased
operation, helicopter flights are performed with the
maintenance operation time are as follows:
doors and windows open for optimum visibility. This
causes water to enter the cabin, bilge areas, and lower
a. The avionic system(s) involved may be open
mounted avionic equipment. During low-level over water
(radomes up, equipment bay doors open, canopies
raised) for extended periods.
b. Maintenance may damage seals and the locking
integrity of fasteners, scratch protective finishes, and
otherwise impart wear and tear to the aircraft.
c. Components may be moved several miles and
exposed to the environment between the removing/
installing activity and the repair shops.
3-25/(3-26 Bl3-25
ank)
