Complex sentence: Newall was appointed Chief of the Air Staff in 1937 and, in that role, supported sharp increases in aircraft production, increasing expenditure on the new, heavily-armed, Hurricane and Spitfire fighters, essential to re-equip Fighter Command.
Split into simpler sentences: Newall was appointed Chief of the Air Staff in 1937. In that role, he supported sharp increases in aircraft production, increasing expenditure on the new, heavily-armed, Hurricane and Spitfire fighters, essential to re-equip Fighter Command.