Revision No.3, July 1945. Approx. 32 'revision' pages for the NIF. These were issued to update previously issued information and should have been put within the file in place of the original sheets. Covers 'dead reckoning', wind determination, altimeters, compass and compass swing, radio compass and receiving set, aircraft sextants, navigational star charts and has notes for the bombardier, radio operator, gunner and so on. These come with the original paper envelope marked with instructions for use etc. Pages good but the envelope is a little tatty. Stock code P13178.