Service Instructions: BT-13A and BT-15 Airplanes By Books / Spiral Bound Transportation › Aviation Publisher: Headquarters, Air Service Command, January 1943 Price $47.01 Free Shipping Send to a friend Collectible - Good Patterson Field, Fairfield, OH: Headquarters, Air Service Command, 1943. Sm to. 180pp. Illus. Good book. Spiral-bound photocopies. Highlighting inside. Technical Order No. 01-50BB-2. (Vultee, Valiant, trainer) Inquire if you need further information. $47.01 1 in Stock at Warehouse Quantity Add Free Shipping to continental U.S. OR $1.00 per item discount if shipped to store.