plate. This procedure varies greatly with different types
of aircraft. You must use the applicable MIM to perform
a leveling procedure.
Make sure that landing gear safety pins are installed.
Make sure that the arresting hook is retracted. Install
arresting book safety pin, or verify that it is installed.
Verify that the landing gear handle in the flight station
is in the DN (down) position. Lubricate exposed
surfaces of the shock strut piston and nose oleo strut with
clean hydraulic fluid.
NOTE: Wiping down oleo struts with hydraulic
fluid helps to prevent them from sticking.
Apply jacking pressure and loosen the lock collar
on wing jacks and nose jack. Lower all jacks evenl y and
slowly, while maintaining preload on tiedown chains by
manually rotating tensioning grips. Lower jacks until
landing gear wheels are on deck and jacks are clear of
jack pads by a safe margin.
Jacks should be promptly removed from the
aircrafts underside to prevent structural
damage to the aircraft in the event of settling.
Make sure that the aircraft main and nose
landing gear struts have settled to their
normal position prior to entering main or
nose landing gear wheel wells. Failure to
allow landing gear to settle could result in
Install chocks and apply parking brakes. Remove
jacks. Remove jack adapters and install/remove aircraft
mooring adapters and tiedown chains as required by the
MIM. Secure the aircraft, and ensure all protective
covers and ground safety devices are installed. Clean up
area and stow all equipment.
AIRFRAME FUEL SYSTEM
Learning Objective: Recognize the different
types of aircraft fuel cells and repair
procedures for integral fuel cells.
Airframe fuel system maintenance is the
responsibility of more than one work center. For
instance, ADs remove and install bladder and
self-sealing fuel cells. Personnel of the AM rating
perform the repairs on integral tanks. Personnel from the
AO rating usually help in the installation and removal
of external tanks (drop tanks).
To meet the particular needs of the various types of
aircraft, fuel tanks vary in size, shape, construction, and
location. Sometimes a fuel tank is an integral part of a
wing. Most often fuel tanks are separate units,
configured to the aircraft design and mission.
FUEL TANK CONSTRUCTION
The material selected for the construction of a
particular fuel tank depends upon the type of aircraft and
its mission. Fuel tanks and the fuel system in general are
made of materials that will not react chemically with any
fuels. Fuel tanks that are an integral part of the wing are
of the same material as the wing. The tanks seams are
sealed with fuelproof sealing compound. Other fuel
tanks may be synthetic rubber, self-sealing cells, or
bladder-type cells that fit into cavities in the wing or
fuselage of the aircraft.
Fuel tanks must have facilities for the inspection and
repair of the tank. This requirement is met by installing
access panels in the fuselage and wings. Fuel tanks must
be equipped with sump and drains to collect sediment
and water. The construction of the tank must be such
that any hazardous quantity of water in the tank will
drain to the sump, so the water can be drained from the
fuel tank. The AM should be familiar with the different
types of fuel tank/cell construction, as described in the
Self-Sealing Fuel Cells
A self-sealing cell is a fuel container that auto-
matically seals small holes or damage caused during
combat operations. A self-sealing cell is not bulletproof,
merely puncture sealing. As illustrated in figure 3-31,
the bullet penetrates the outside wall of the cell, and the
sticky, elastic sealing material surrounds the bullet. As
the bullet passes through the cell wall into the cell, the
sealant springs together quickly and closes the hole.
Now some of the fuel in the tank comes in contact with
the sealant and makes it swell, completing the seal. In
this application, the natural stickiness of rubber and the
basic qualities of rubber and petroleum seal the hole.
This sealing action reduces the tire hazard brought about