TWO:"Yes," she said, "I heard it. But I was not frightened. What was it?" He did not know, he said, and she sent him back to the barracks.Of course, if the airplane was on a cement apron in front of the hangar, it would be all right to start the engine there. But in sandy ground, or on a dusty apron, Id be sure the tail wasnt pointed so the propeller blast would throw dust on planes or on people.