1. Ensure threads are not damaged
2. Install nose plug, tighten with spanner wrench
or rachet, and tighten nose setscrew.
Electric/Electronic TaiI Fuzes
Procedures for inspection and installation of tail
fuzes FMU-139 and Mk 376 are the same as for GP
bombs, as outlined previously in this chapter.
Mk 89 Mod 0 Spotting Charge
Prepare and inspect the Mk 89 spotting charge
adapter (fig. 13-16) as follows:
1. Remove tape holding cotter pin with instruction
2. Remove inertia sleeve and compression safety
spring by unscrewing firing pinhead from adapter body.
3. Inspect all components, and reject adapter if any
components are damaged.
Mk 4 and CXU-3 Cartridge
Install signal cartridge in spotting charge adapter as
1. Insert inertia sleeve into cavity body.
2. Slide cartridge through inertia sleeve with
cartridge rim against forward end of sleeve.
3. Press blocking pin inward until safety pin
presses through the second guide hole, locking blocking
pin in place.
4. Insert cotter pin through outer set of holes in
head of safety pin and safety pin sleeve. Bend leg of
cotter pin slightly to hold in place.
5. Place compression safety spring over firing pin
head into adapter body and hand tighten.
Mk 89 Spotting Charge
Install Mk 89 spotting charge adapter with signal
cartridge as follows:
1. Verify bomb tail well is clean.
2. Insert adapter in the same manner as electric
NOTE: The procedures for inspection and
installation of nose fuzes and bomb fins are the
same as those discussed previously in this
chapter for GP bombs.
GUIDED-BOMB UNIT (GBU)
GBUs are general-purpose bombs configured
with a wing assembly and a computer control
group. Preparation and inspection of the GBUs are
the same as the GP bombs, discussed earlier in this
Wing Assembly Installation
Install the wing assembly on the bomb as follows:
1. Ensure safety pins are securely installed in
latch release lever and collar assembly (fig. 13-17).
2. Remove access covers.
NOTE: Refer to figure 13-18 for steps 3
Attach Mk 3 arming wire to aft suspension
Insert arming wire through MAU-166 swivel
Orient wings as follows:
a. Position GBU-12 and GBU-16 wings in X
configuration with the wing release latch mechanism at
9 oclock, with the bomb lugs at 12 oclock when viewed
from the rear.
b. Position GBU-10 wings so that latch
mechanism is at 12 oclock in line with the bomb
NOTE: Mk 3 arming wire installation for the
GBU-12 and GBU-16 is the same as for GP
bombs, discussed earlier in this chapter. For
the GBU-10, install arming wire through hole
at the 3 oclock position of wing and route
through pull-out pin/gagrod and pass wire out
through hole at 9 oclock position of wing
6. Remove safety cotter pin from pull-out
7. Keep arming wire taut while pressing the wing
against the bomb body. Hand tighten setscrews.
8. Torque setscrews to the required torque.