POSITION ANGLE

spotting enemy airplanes is your big job as a sky look out you search your sector and report everything you see as soon as you see it to report a plane so it can be spotted instantly by others you must first describe its location by its relative bearing and then its height by means of its position angle this is the angle your line of sight to a plane makes with a horizon this angle is called the position angle because it gives the exact position of the plane above the horizon the arch of the sky above you describes a half circle divided in two degrees the point directly overhead the zenith measures 90 degrees from either horizon as a plane approaches your ship flying at constant speed and altitude its position angle increases very slowly until it reaches 25 degrees reported position angle 25 then the angle increases more and more rapidly 30 35 40 45 50 55 now it increases very rapidly until it reaches niner-zero directly overhead as you watch a plane flying toward you it seems to rise even though it's flying straight and level this apparent rise is actually the increase in its position angle out here long before it reaches position angle 25 is where a plane should be spotted and reported if you're going to give your ship time to get its air defense into action not here after position angle 25 if it is to be shot down or turned away if a plane can manage to sneak in undiscovered until it reaches it bomb release point at position angle 55 it will be too late for any defensive action the plane will have dropped its bombs your job as a sky look out is to keep watch and spot all planes in your sector when you see a target report its relative bearing and keep your binoculars trained on the plane so your telephone talker can read and report its position angle by spotting and reporting every plane while its position angle is still small you'll do your job in guarding against enemy air attack I