Instructions for firings against aircrafts
The complex question of the organization and the employ of the a/a units was fully defined with the Инструкция за артилерийските ПА взводове, картечни постове и команди пехота по отбраната срещу въздушен противник (Instructions for the artillery a/a sections, machine guns posts and infantry commands on the defence against air enemy) published on 14 December 1915. The aim of the text was to fix a uniform firing method, to arrange the observation and the reconnaissance, to provide the knowledge of the appearance of the Bulgarian aircrafts, and to favour the cooperation between the a/a artillery and the air force. The Instructions were constantly updated, with additions containing corrections and improvements, according with the innovations introduced by the German Army.
At first the
fire against air targets was regarded like the fire against land targets
moving quickly. The usual procedure in this case was to obtain a
the return of the officers, who had attended a course in
– direct fire (директна стрелба), that could be carried out in three different ways :
a) free fire (свободна стрелба) : the gun commander used only the firing data, without any special device for firing against air targets. He estimated the actual distance of the aircraft by means of a rangefinder, the altitude by means of an abacus with graduated ruler fixed at the right side of the rangefinder, the angle of sight and the actual azimuth, then he obtained the “future” datas, determinig directly the movement of the aircraft by tables and the survey of measures made during an exact lapse of time;
b) fire with tables (стрелба с таблици) : the gun commander estimated the distance, the altitude, the actual speed and the flight angle of the aircraft, then he obtained the firing data deductively by means of tables which divided the sky in sectors with a fixed altitude, that is 2000m, 2500m, 3000m and 3500m. These tables had been obtained firing a great number of testing shots with a 77mm field gun 96 n/a arranged to fire against aircrafts, and were truly effective only with this kind of gun.
fire with flight predictor (стрелба с летимер) : the gun
commander obtained all the firing data by means of the “Auswanderungsmesser
(Am.) Peres”, developed by the firm Karl Zeiss (
– indirect fire (индиректна стрелба) : the gun was aimed directly at the point where the aircraft was coming thanks to the “Kommandotafel Jacob”, that gave the azimuth, the declination of the barrel and the setting of the fuze; the elevation angle was obtained with the range dial and the lateral deflection with the firing table;
– barrage fire (преграден огън) : it was used to fire at night against targets that could not be seen. It required the development of a rigorous firing plan, assigning to every gun a sector to be fired on and the height of bursting of the shells.
As for the
observation and the reconnaissance, the Instructions
ordered that every battery and section established observation posts, with a
specially trained observer equipped with binoculars. He should carefully
watch the skyline, trying to locate the arrival of enemy aircrafts also by
means of the noise of their engines. A net of observation posts was
In order to
favour the knowledge and the cooperation with the
For his part, the Bulgarian air force should inform the a/a units about all the flights of friend aircrafts. If the flight of an aircraft had not been reported, to avoid hitting it by mistake, the heads of the airports should call it back, before it entered into the firing area. The Bulgarian aircrafts were signalled also by green and red rockets.