follow when working with these fuzes. Refer to figure
13-6 for arming wire installation.
MK 376 ELECTRIC TAIL FUZE.— Prepare,
inspect, and install the fuze as follows:
1. Ensure that the safety pin is installed in the
pop-out pin.
2. Remove shipping cap.
3. Ensure moisture or foreign material is not
present in the electrical connector at base of fuze.
4. With thumb, push in on pop-out pin, remove
safety pin from pop-out pin.
5. Ascertain if resistance from pop-out pin against
thumb is present.
6. Reinstall safety pin into pop-out pin.
7. Loosely install fuze restraining clip on the flange
of the fuze.
8. Install fuze into tail fuze well, and tighten with
spanner wrench until flange is seated.
9. Align pop-out vertical with bomb lugs; tighten
fuze restraining clip.
FMU-139 ELECTRONIC TAIL FUZE.—
Prepare, inspect, and install the fuze as follows:
1. Ensure that gagrod is secured by safety pin.
2. Verify that red and black striping is not visible
on gagrod sleeve.
3. Check fuze for exterior damage, moisture, and
corrosion.
4. Remove plastic shipping plug and flag from
connector on the end of the fuze.
5. Set the fuze switches as follows:
a. Check that the low-drag arm/delay fire
switch is set to X-position.
b. Rotate high drag arm/delay time switch as
required. It must be in a 2.6 sec position for
Navy/Marine aircraft.
6. Align faceplate with bomb lugs. Insert fuze into
tail fuze well.
7. Install and tighten closure ring. The fuze may
spin slightly.
Mk 122 Arming Safety Switch
Remove, inspect, and install the Mk 122 arming
safety switch as follows:
1. Remove the Mk 122 arming safety switch from
its package.
2. Inspect the Mk 122 arming safety switch for
deformation, corrosion, and damage to the case. Check
the contact assembly for cleanliness. Check the coaxial
cable for cracks and breaks in the insulation, and be
careful not to stress the coaxial cable.
3. Install the Mk 122 safety arming switch as
follows:
WARNING
The Mk 122 arming safety switch must be
installed in a RADHAZ-free environment
Do not pull the lanyard during handling
and loading. If the lanyard breaks away
from the switch, discard the entire
arming safety switch so it will not be used on
a bomb. Do not attempt to replace the
lanyard.
CAUTION
When installing or removing the weapons
carrier and while handling the weapon, be
particularly careful to avoid damaging the
safety switch. When using a Mk 49 Mod 1
weapons carrier, do not install the safety
switch until the weapon has been
positioned on the skid adapter. Failure to
orient the switching unit retaining nut
can result in damage to the arming safety
switch.
a. Plug the male connector of the switching
unit firmly into the bomb charging receptacle,
piercing the diaphragm. Then, slide the switching
unit retaining nut, threads down, over the cable and
lanyard.
b. Secure the arming safety switch in the bomb
charging receptacle by screwing the switching unit
retaining nut into the bomb and tightening it with the
wrench supplied. When the nut is seated on the top of
the switching unit, back it off until the flattened sides of
the switching unit retaining nut are at right angles to the
length of the bomb and the coaxial cable is aft of the
lanyard.
c. Insert the free end of the cable through
the nearest bomb suspension lug to safeguard the
cable.
13-6
