You are all aware of the problems associated with the title of this lecture and, m order to avoid overlapping with Mr Hafner, I shall limit my part to the work that has been carried out on the Skeeter

In many respects the helicopter resembles an aircraft engine unit, and it therefore suggests itself that the routine method of testing engines should be applied to the helicopter Indeed at the beginning of 1951, a draft proposal to this effect was put forward, and is as follows

• (1) The aircraft should be tested for functioning on the ground followed by the strain gauging of its transmission, control and rotor systems During the strain gauging a complete range of flight control should be covered

• (2) Records made of these tests should be examined for any undue stress levels and stress oscillations

Had Daedalus, prior to his legendary flight from Crete on wings of wax and feathers, resorted to a little ground testing under simulated flight conditions, he would possibly not have lost his son Icarus and the art of aeronautical engineering might have joined the ranks of the great classics However, this Greek aircraft designer did not happen to have on this occasion the benefit of a development contract for such test work Indeed, I understand the whole venture was undertaken strictly without the authority of the local Ministry of Aviation, and so the chances for a successful completion of this note-worthy effort were somewhat restricted The designer then, very wisely and no doubt realising the short-comings of the situation, advised strict adherence to a very limited flight envelope, so that there would be a safety margin for contingencies during the ensuing flight

It is a good thing to occasionally lift our sights from the job in hand and focus our attention on the broader purpose of our actions For example, if we ask ourselves what the purpose of maintenance is, we might answer that it is to keep the equipment we are using in a condition which does not fall below a certain standard In the narrow sense, a definition of some such sort would pass, but surely, if we accept it as a complete answer to our question, we are really saying that maintenance is an end unto itself This, of course, is quite ridiculous because maintenance is not just done for the fun of it, rather its purpose is to carry out certain work, m close association with quite different types of work, so that the integrated effort enables the equipment in use to satisfactorily perform the task in handm the case of a commercial airline, this would be to earn money by giving the best possible public service Some such reply I think would be a more complete answer to our question

I should like to commence by referring to the remarks made during the all-day discussion on Helicopter Maintenance organised by your Association in co-operation with the Society of Licensed Aircraft Engineers, which was held on 21st October, 1950 Reference was then made to the practical difficulties of drafting the requirements for helicopter licensing because of the relatively short duration of the experience which candidates would have had at that time It was said that there was no doubt that the requirements would be amended as soon as it was possible for engineers to have had the minimum experience required by the Board This stage was reached early last year and Section “L” of British Civil Airworthiness Requirements was re-issued on 1st April, 1952

When asked if I would contribute to this afternoon's discussion I wondered what there was that I could say in such a field as Standards of Maintenance Coming from the Design side of this vast organism the Aircraft World and having had very little to do with the maintenance of aircraft, let alone helicopters, m what way could I contribute when there were so many other far more knowledgeable, capable and experienced people and, in any case, when were the Design side concerned about maintenance of anything, their heads always in the clouds, hovering at Mach numbers of one or above with a safety factor of 15?