3. When unsatisfactory flight characteristics are
reported by the pilot that cannot be traced to a flight
control system malfunction or improper aircraft loading
4. When the “Weight and Data” handbook has been
lost or damaged
BALANCE
An aircraft is said to be in balance, or balanced,
when all weight items in, on, or of the aircraft are
distributed so that the longitudinal center of gravity (cg)
of the aircraft lies within a predetermined cg range. This
range is defined by the most forward and aft permissible
cg locations, which are called the forward and aft cg
limits, respectively. To determine if an aircraft is
balanced, the aircraft cg must be calculated and
compared to the forward and aft cg limits for that
particular configuration and gross weight.
Learning
AIRCRAFT HOISTING
Objective: Recognize the different
types of slings and the hoisting requirements
for naval aircraft.
There are three main conditions that might require
you to hoist an aircraft or its components. They are
aircraft mechanical problems, ship mechanical
problems, and aircraft mishap afloat or ashore. Aircraft
lifting slings are specialized items of support equipment
whose function is to aid in the hoisting of aircraft and
aircraft components. Each airframe has structural lifting
points for the attachment of a sling designed to lift that
aircraft or aircraft subassembly. Slings are used to hoist
aircraft from the pier to carrier deck, clear crash-
damaged aircraft, and to remove and install engines and
other components during maintenance operations. In
general, slings are hand portable and attach to a single
suspension hook of a crane or other hoisting equipment.
LIFTING SLINGS IDENTIFICATION
Aircraft lifting slings are constructed in accordance
with Military Specification MIL-S-5944, and can be
classified under four types of construction or
combinations of type. The four types are the wire rope,
the fabric or webbing type, the structural steel or
aluminum type, and the chain.
Figure 3-21.—Typical steel/aluminum sling.
Wire Rope
Slings of this type employ wire rope or cable. The
wire rope sling is the most common type, and it
combines high strength, ease of manufacture, and a great
deal of flexibility for compact storage. There are two
basic types of wire rope slings. The simplest is a
multi-legged wire rope sling with an apex lifting link.
The other is one built with structural steel or aluminum
in combination with wire rope supports. See figure 3-20.
Fabric or Webbing
Fabric or webbing type slings are generally reserved
for lifting lightweight objects, or applications where
contact between wire rope and the component being
lifted could result in damage.
Structural Steel or Aluminum
Slings of this type are constructed with plates,
tubing, I-beams, and other structural shapes, and they
do not contain flexible components. See figure 3-21.
Structural steel and aluminum slings are generally
compact in size, and they are often used for lifting
aircraft subassemblies.
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