Can you give an example?
Akash was tested many times by the air force and army, after that only made orders worth multi billion dollar.
User Trials
IAF had evolved the user Trial Directive to verify the consistency in performance of the total weapon system against low flying near range target, long range high altitude target, crossing and approaching target and ripple firing of two missiles from the same launcher against a low altitude receding target.
The user trials of intercepting flying targets were conducted at ITR, Chandipur during 14-21 Dec 2007. Akash missile has successfully intercepted targets fifth time in a row in this campaign. Fifth and last trial successfully took place at 2.15 pm on 21st Dec at Chandipur on sea. The Akash missile destroyed an Unmanned Air Vehicle (Lakshya) which was flying a path simulating an air attack. The target vanished from the radar screen when the missile was guided precisely in close proximity and warhead blast occurred destroying the target instantaneously. This is the grand finale of the tend days users campaign meticulously planned by the Indian Air Force.
Indian Air Force officials witnessed user trials. With the conclusion of Akash evaluation now onus lies with Indian Air Force and Indian Army as the state-of-art surface to air missile as required by services is available for indigenous production in India.
AKASH AIR DEFENCE WEAPON SYSTEM