Attack aircraft provide the air arm of the Navy striking force. These Marine Corps and Navy aircraft are required to perform close air support and strike missions in direct support of ground and sea operations. Of utmost importance in these missions is accuracy and first-pass attack capability against a wide variety of targets, stationary and moving, during day and night conditions. A major portion of these operations is conducted in visual flight conditions not requiring the sophistication, cost and complexity of all-weather delivery systems.

Recent technological advancements have made guided weapons using laser, TV or infrared seekers possible for use in these missions. The weapons, although effective, are not always cost effective or operationally desirable in all situations. There exists a need for an accurate delivery method for air launched conventional unguided weapons in order to give the air forces the required flexibility for the best possible neutralization of all enemy target threats.

The A-4M weapons delivery system is intended to provide the Marine Corps with an accurate bombing system for use in close air support against targets in close proximity to friendly troops. The weapons system will deliver guided and unguided ordnance under day and night conditions but will not have an all-weather capability. The system is expected to operate in an environment which exposes the aircraft to hostile missile attack and ground fire, therefore making accurate first-pass weapon delivery an imperative requirement.

The method used to achieve high accuracy in the unguided weapon delivery is angular rate bombing. The system will consist of DMT, computer, and head-up display. Working together as an integrated system, pilot steering information and selectable automatic weapon release firing pulses will be generated for both visually acquired targets (TV mode) and laser designated targets (laser mode). The system will be designed to be physically and functionally compatible with the A-4M and AV-8 aircraft.

The Marine Model A-4M Skyhawk is a single place attack aircraft. Designed as a high performance aircraft, it mounts two 20 mm guns internally, carries a wide variety of external stores, and is capable of operating from a carrier or shore base. The current weapon delivery system is composed of several independent subsystems integrated into the aircraft. The primary weapon delivery system is the CP-741. These systems are limited to relatively canned weapon delivery maneuvers in visual daylight operation. Current night close support operations are conducted with the aid of flares. More effective and accurate weapon delivery is a basic requirement for the A-4M aircraft.

The U.S. Marine Corps AV-8 attack aircraft, known as the Harrier, is designed and built by Hawker-Siddeley of the United Kingdom. This aircraft is a single seat, single engine, transonic vectored thrust designed for vertical or short take-off and landing (V/STOL). The Harrier is characterized by two forward and two aft rotatable nozzles, shoulder mounted swept anhedral wings, and a bicycle landing gear with outriggers at the wing tip. Except for V/STOL capability, the Harrier is similar in size, weight, and performance to the A-4M aircraft. Two Aden 30 mm guns may be carried in fuselage pods in addition to the five ordnance pylons. The current Harrier weapon delivery system is a part of the Ferranti FE-541 integrated navigation and weapon aiming system which utilizes an inertial platform as a primary sensor. Aircraft delivered to the Marine Corps after Mod 800 will have the FE-541 system replaced with a less complex and lower cost system termed the interface and weapon aiming computer (IWAC) provided by Smith's Industries, Ltd.