Identification of a Fully or Partially Armed Fuze

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 installation. 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 A1. A2. A3. A4. A5. A6. 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 result. 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 isn’t 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. Q1. Q2. Q3. 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. . 1-12