Complex sentence: Only five years after the delivery of the Lightnings, the KAF decided it needed an aircraft with better serviceability; it had been using the Hunters and the Strikemasters in the interceptor and ground strike role, rather than the Lightnings.
Split into simpler sentences: Only five years after the delivery of the Lightnings, the KAF decided it needed a better serviceable aircraft. It had been using the Hunters and the Strikemasters in the interceptor and ground strike role, rather than the Lightnings.