The surest way of improving the design of aircraft structures appears to be by anextension of the “team spirit,” whereby the experience andknowledge of everyone engaged in the craft are pooled and focussed on anyproblem requiring solution

For instance, when a pilot flies a machine he discovers its good and bad points,and, knowingly or unknowingly, compares it instinctively with every othermachine he has flown On returning to earth he naturally communicates his opinionto others In the course of time his views reach the ears of the designer, who,also, naturally adapts the design to meet any criticism The ultimate result isthat the experience of every pilot, and not only of every pilot, but ofeverybody dealing with the aeroplane, is gradually pooled for the purpose ofimproving the design

It is to be noted that it is usually extremely difficult or impossible tointerpretate this experience mathematically, because there are too many unknownfactors operating

It is well known that by employing aero-photogrammetric methods and instruments one is able to produce maps in considerably shorter time and at much lower cost than is possible when the work is done according to the old terrestrial methods This saving of time and money will, however, vary according to whether a sufficiency of terrestrial bases is already known or not For it is, indeed, a fact that in the hitherto practised aero-photogrammetric methods most of the time was spent in finding at least three fixed points for every plate-pair which were recessary to make an exact setting into the plotting instrument possible If such terrestrial measurements have to be carried out in difficult country, for instance in primeval forest areas or extensive swamps, it cannot but happen that the expenditure of time and money will be so greatly augmented that in the end the whole advantage of aerial survey becomes illusory