As spring came on, Hal went from ground work back again into air flight. He found the routine of flying tests easy, because the inner workings of engine mechanics seemed etched on his very brain. The feel of wings stirred him, roused all the old wild exhilaration of flight. And yet he was more critical of air machinery than in the past. Where before he had been vastly satisfied with the mechanisms of man-flight, he now caught himself wondering continually why man had not made his machines the better to withstand certain shocks that were bound to come in any flying routine. Flying gear had made progress, but landing gear was still crude, still based on land-moving machinery, instead of machinery of the air.