Complex sentence: This aircraft was accepted by the Army Air Forces on 30 August 1945, whose officials were so impressed by the aircraft, while still in development, that they ordered the first production P-82Bs in March 1945, fully three months before its first flight.
Split into simpler sentences: This aircraft was accepted by the Army Air Forces on 30 August 1945. AAF officials were so impressed by the aircraft while still in development that they ordered the first production P-82Bs in March 1945, fully three months before the aircraft's first flight.