MIL-STD-2088-SUP-2 Bomb Rack Unit BRU, Single Store, AircraftThis standard establishes the general guidelines and criteria for the design and development of a single store bomb rack unit BRU for carriage and release of airborne stores excluding air-to-air missiles from fixed wing and rotary wing aircraft using a single suspension point or suspension points spaced at 14 or 30 inches. This standard addresses detailed requirements for gravity non-ejected, pyrotechnic, hydraulic, and pneumatic powered BRUs. Mechanical aircraft armament interoperable interfaces are incorporated to enhance cross utilization and servicing capabilities between military aircraft and aircraft stores see 3.1 of all services of the Department of Defense DoD and North Atlantic Treaty Organization NATO nations.

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MIL-STD-2088B

interfere with BRU functions such as the operation of the mechanical fuze AUs, ejector pistons, and swaybraces. The procuring activity shall determine the maximum number of positive arming attachments. The positive arming attachment spring latch assembly shall be as specified on NAVSEA drawing 2263759, or an equivalent hard point shall be provided. The axis of the latch shall be located approximately 1 inch above the uppermost surface of the store body and attached to the side of the BRU. The positive arming attachments shall be positioned in a manner to preclude opening in flight from aerodynamic loading. If the BRU is required by the procuring activity to provide an electrical fuze AU (see 5.1.4.2) then one positive arming attachment shall be positioned at the location specified in Note 5 of Figures 1 and 2.

5.1.5 Swaybraces. Automatic, semi-automatic, or rapid activating BRU swaybraces shall be provided for all stores after independent activation of both vertical supports supporting the store. Swaybraces shall be located symmetrically about vertical supports as shown on Figures 1 and 2 and laterally within the reinforcement area of MIL-STD-8591 (STANAG 3575 AA and AIR STD 20/10). The swaybraces shall be capable of reacting the design loads without the use of adapters. For standardization purposes, as a minimum, the swaybraces and related BRU systems shall accommodate store diameter as follows:

SUSPENSION DIAMETER

14-inch 8.0 to 20.0-inch

14/30-inch 8.0 to 20.0-inch for 14-inch

8.0 to 30.0-inch for 30-inch

Swaybraces shall be designed so that they cannot apply excessive loads to the store or BRU to prevent store release. After all swaybraces have been activated, the store shall be held securely in all three axes until separation of the store. The application of the swaybraces at any point shall have a centering action on the store that tends to keep the store symmetric about the BRU vertical axis. The contact of the swaybraces to the store shall exhibit at least line contact on a store conforming to MIL-STD-8591. The swaybraces shall not require any scheduled maintenance nor be susceptible to damage by sand, dust, or supersonic airflow impingement. The swaybraces shall be capable of interfacing with stores having reinforced areas as specified in MIL-STD-8591.

5.1.6 Safety interlock. The BRU shall contain a safety interlock mechanism that interrupts both the BRU's electrical initiation control circuit and its mechanical store support latch release operation (STANAG 3575 AA and AIR STD 20/10). Each of the two interrupts shall be removed as a result of separate and distinct events as detailed in the following paragraphs.

5.1.6.1 Safety interlock status. The safety interlock mechanism shall have a minimum of two distinct position settings: SAFE and ARMED. If the BRU requires ground operation with stored energy present, then a third position, GROUND, may be required. With both the electrical and mechanical interrupts in place, the safety interlock shall be in its SAFE position.