This accession contains Air Corps Performance Tests of aircraft. There are ninety four seperate booklets and they have individual specifics, graphs, weights and measures etc on different makes of airplanes.They have notes where pilots made their remarks, and signoff's by the highest ranking officer. Also stamped inside is the certification canceled signature, grade, and date. Majority have War Department Air Corps Engineering Division, McCook Field, Dayton Ohio on inside front cover and on the outside, on the front of booklet, it has Lockheed Aircraft Corporation, Burbank, California.