4AP (4 Actions Plus, multi-function programmable fuze) is a state-of-the-art electronic fuze, programmable in the gun or by portable fuze setter. The design is optimized in order to have very high performance and reliability, and low cost.
The main programmable functions are: target proximity, height of burst, time, point detonation, delayed point detonation. It is also possible firing the fuze in the “Automatic Mode”, suggested as default mode, performing both target proximity and height of burst functions. Point Detonation function is always active as back-up (except for delayed impact mode).
Proximity and height of burst algorithms are state of the art, assuring an optimal detonation instant, and ECCM capability.
The fuze is safe according to STANAG 4187: the fuze Safety And Arming Device is mechanical, with an interrupted explosive train, and includes two independent safety features, based on two different stimuli, that can happen only after the projectile firing action (set-back acceleration and in-flight spin).
External layout of 4AP fuze is the standard profile defined in STANAG 2916 Ed.2, § A-1. This feature allows the fuze to be fitted on several ammunition calibers, with standard cavity and thread. For ammunition having a bigger cavity, it is possible to use mechanical and pyric adaptors.