Figure 1-6.Mk 346 fuze with Mk 68 thermal shield installed.
The Mk 68 thermal shield (fig. 1-6) protects the fuze
and adapter booster when used in the Mk 82 Mod 2
thermally protected bomb. The fuze is hand-pressed
into the booster. The base of the shield covers the
exposed portion of the adapter booster after fuze/shield
Identification of a Fully or
Partially Armed Fuze
Normally, the Mk 346 fuze is removed from an
unused bomb, returned to its shipping container, reset,
and reinstalled for a subsequent mission. However, if
an arming wire is lost or the arming wire installation is
faulty, first stage arming can occur while the bomb is
aboard the aircraft. You can identify the first stage
arming condition by the red band covering all or part of
the safe-arm observation window on the body of the
fuze. You should examine all unused bombs returned
from a mission as soon as possible. If evidence of a
malfunction is present, immediately remove the fuze
from the bomb while on the flight deck. A partially
armed fuze is safe for handling and disposal; however,
if the fuze is jarred or dropped, complete arming may
Second stage arming of the fuze does not occur
unless first stage arming is complete and the fuze is
accidentally jolted or jarred. Then, the fuze is locked in
the bomb and isnt easily removed. This condition is
unlikely, but it could happen with a hung bomb, or with
a bomb that is inadvertently released because of a bomb
rack structural failure. This is a dangerous situation. If
a safe condition is in doubt, immediately notify
explosive ordnance disposal (EOD) personnel.
REVIEW NUMBER 4
What is the range of the functioning delay time
on the Mk 346 mechanical long-delay tail fuze ?
At what point does second-stage arming of the
Mk 346 fuze begin?
The difference between the Mk 3, 4, and 5 arming
assemblies is the .
REVIEW NUMBER 3 ANSWERS TO QUESTIONS Q1. THROUGH Q6.
The Mk 20 and Mods are used with the Mk 339 mechanical time fuze
The characteristics shared by Mod 0 and Mod 1 of the Mk 339 fuze are
nose-mounted, air-enabling, and detonator-safe.
The primary and option delays of the Mod 0 and Mod 1 fuzes can be changed by
adjusting the primary and option time-setting dials.
You can tell if the fuze has shifted from the primary to the option delay by checking
the time setting observation windows of the fuzes.
Safe Tip of indicator pin does not extend into bubble.
Armed Indicator pin extends into bubble.
Safe Green foil is intact.
Armed Green foil is pierced by the indicator pin.