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Unless German scientists have developed a sight allowing accurate bombing out of turns, glides or climbs, maximum danger period of a Nazi level-flight bomber is in his approach to his target. For coming up to his bomb-release line he must fly in a straight line and at a constant altitude for about 60 seconds (more than three miles at 200 m.p.h.), to give his bombardier time to draw a bead. It is there that he is the best target for the antiaircraft guns. On likeliest directions of approach anti-aircraft guns are most heavily established. The batteries are so placed that the tops of their inverted cones of effective fire (see lower cut) overlap. Because it is better to wing a bomber before he drops his load than after, fire cones are heavily overlapped ahead of the lines where enemy bombers are likely to drop their eggs.
On a bombing raid, a Heinkel bombardier, who is also second pilot, rides up forward in the nose ("meat-can" to U. S. Air Corps big-ship crews). There he has a machine gun, convenient in case his ship is jumped by enemy pursuit. Back of him sits the pilot, still farther back two machine-gunners to deal with pursuit attacking from behind. The top gunner rides in a wind-screened cockpit looking for attacks from above. The gunner on the bottom rides in a "dust-bin," on his belly, to range his guns on pursuits attacking from below.
Approaching the target, the bombardier leaves his seat, crouches or lies down flat over the bombsight just below his machine gun. Quickly he checks the spirit levels to be sure that the ship is parallel to the ground, other settings that correct for the speed of the plane and the wind drift (which slows a bomb, speeds or deflects it). Then he puts his eye to the eyepiece and takes his sight on his target. From that point until the bombs are dropped the bombardier is in charge of the ship. Training his sight on the target he may well find (and usually does) that the pilot is not flying straight toward the target. On the pilot's board an instrument signals that he is right or left of the sighting line. Providing he holds the true line and keeps constant altitude the rest is up to the bombardier. Down the groove flies the Heinkel with its belly bomb-bay doors open. As it gets into range, the bombardier presses the bomb-release button. If he has set his selector for one bomb, only one falls toward the target. If he has set it for salvo-bombing, all drop. Air Corps enlisted men call this "opening the tail gate."
What changes the Germans have added to such fundamental procedure the Germans are keeping to themselves. One possibility is that they have done away with the bomb-release button, use a photoelectric cell built into the sight to drop the bombs when the sight is on the target. Purpose of mechanical dropping is to avoid a lapse sometimes as long as one-fifth of a second between the time a bombardier sights the target and the time his mind has telegraphed the button-pushing impulse to his fingers. Split seconds in the releasing operation make yards of difference on the ground.