Complex sentence: When the Hawker engineers found out, they issued a formal objection, saying that the plane had not been designed for that purpose; however, Swedish pilots proved that the aircraft was up to that task and dispelled their concern.
Split into simpler sentences: When the Hawker engineers found out, they issued a formal objection, saying that the plane had not been designed for that purpose. But the Swedish pilots proved that the aircraft was up to that task and dispelled their concern.