Why do we need devices to teach pilots how to fly in bad weather? For thousand of years the cavalry galloping across the plains, or the mariners in sailing ships never needed such things – why do we need them now?
When walking along a trail in a forest at night without any light we know which way is up by our inner-ear balance mechanism and the sensation of gravity. When a pilot is flying in good weather the horizon shows where ‘up’ is. However, when flying in poor visibility – rain, fog, snow, darkness – the balance mechanism of the inner ears becomes confused and the pilot will have no idea where ‘up’ really is. If the plane starts to turn gently the pilot will be unaware of this. He may notice that the compass is turning and the airspeed is increasing and will apply corrections. But without reference to the ground the corrections may lead to a spiral dive with tragic consequences.
Instruments were developed in the late 1920s that mimicked the horizon – known as the artificial horizon – regardless of the attitude of the aircraft. Thus a pilot could fly in adverse weather and still have a picture of the aircraft relative to the horizon. Aviation technical pioneers such as Elmer Sperry (artificial horizon and gyroscopic compass), Paul Kollsman (altimeter) and the Bell Telephone Co. (radio communication receiver), combined with the determination of James Doolittle, perfected the art of ‘blind flying’ as flying by reference to instruments was then known.
For the complete article please see the attached pdf.