The Thirty-third Wilbur Wright Memorial Lecture was delivered before the Society on Thursday, May 31st, 1945, at 6.30 p.m., in the Lecture Hall of the Institution of Mechanical Engineers, Storey's Gate, London, S.W.I, by permission of the Council of the Institution. The chair was taken by Sir A. H. Roy Fedden, F.R.Ae.S., President of the Society.

Test Flying should not be confused with Flight Testing. There is a very large difference between the two. Flight Testing covers the work of an infinite variety of people, while Test Flying is done by pilots and observers only. It is with the work of the pilots that this paper will deal.

A Test Pilot is presumably a pilot who tests aircraft, but it is a very loose, term. Out of the multitude of pilots engaged on test work in aircraft, only a small percentage actually test the aeroplane itself, while the remainder may be divided into two classes: those who do flight inspections, and those who use the aircraft merely as a vehicle for the testing of equipment and engines.

In this lecture the aim is first to establish of position of “airworthiness” in the field of “safety”. To draw a comparison, airworthiness is but one element of a complex jigsaw puzzle in which all the pieces must properly interlock in order to produce a satisfactory safety picture. This parallel applies too in the sense that if the shape of one of the elements is altered, all the adjacent elements must be altered to maintain a perfect fit. Arising from this, it is clear that, if safety and efficiency of air transport are to increase, then airworthiness provisions must be ever more closely linked with the conditions under which the aeroplane operates. The second aim is to draw attention to those airworthiness matters to which the designer could most profitably direct his efforts.