replacing whenever necessary to keep them in
good condition. Some of the aircraft parts that
require bonding are identified below.
Control surfaces. Each control surface should
apply to trim tabs.
Engine mounts. Use at least four bonding
jumpers across each engine mount support. This
provides a current path between the engine mount
and aircraft structure.
E n g i n e cowling. Use at least four sym-
metrically placed bonding jumpers to bond the
engine ring cowling to the engine across the rubber
mounts at the front end of the cowling.
Equipment mounts. Place bonding jumpers
across shock mounts supporting electrical and
radio equipment and the instrument panel.
Methods and Materials
You should install bonding connections so
Figure 2-23.-Bonding methods.
they won't break or loosen. This prevents a
variation in the resistance during movement. One
primary objective for bonding is to provide an
CABLE LACING AND TYING
electrical path of low dc resistance and low RF
impedance; therefore, it is important that the
Wire groups and bundles are laced or tied to
jumper be a good conductor of ample size. Make
provide ease of installation, maintenance, and
the bonding wire as short as possible. Bond parts
inspection. Lacing or tying keeps cables neatly
directly to the basic aircraft structure rather than
secured in groups and avoids possible damage
through other bonded parts, insofar as practical.
from chafing against equipment or interference
Install bonding jumpers so they do not interfere
with equipment operation.
with aircraft movable components. (See fig. 2-23.)
You tie a group or bundle of wires by using
Contact of dissimilar metals in the presence
individual pieces of cord tied around the group
of an electrolyte, such as salt water, produces an
or bundle at regular intervals. You lace a bundle
electric action (battery action), which causes
or group of wires by securing them together inside
corrosion in the connection. The intensity of this
enclosures by a continuous piece of cord. You use
electric action varies with the kinds of metals.
this cord to form loops (half hitches) at regular
Bonding frequently causes the direct contact of
intervals around the group or bundle.
Cotton, nylon, or fiber glass cord are used to
dissimilar metals. In such cases, the metals used
are of the kind that produce minimum corrosion.
tie or lace. The cotton cord has a wax coating to
make it resist moisture and fungus.
You should make connections so that if there is
corrosion, its in replaceable elements such as
jumpers, washers, or separators.
SLEEVING
Don't use self-tapping screws for bonding
purposes. Jumpers shouldn't be compression-
Sleeving helps protect connections from
fastened through plywood or other nonmetallic
accidental shorting and moisture and to lengthen
the arc-over path between contacts. Don't use
material. When you are performing a bonding
operation, clean the contact surfaces of insulating
insulating sleeves on connections or connectors
finishes or surface films before assembling. After
that require moistureproofing. Don't use sleeving
installation, refinished the assembly with a
on connectors that have a sealing grommet that
suitable protective finish. You should refer to
covers the soldered connection.
NAVAIR 01-1A-505 for detailed information
Sleeving, commonly called spaghetti, has
many applications in naval aviation. Some of the
about bonding procedures.
