1st Search Attack Group The 1st Search Attack Group was a United States Army Air Forces ( AAF ) unit . Its last assignment was with the First Air Force . The mission of the group was the development of equipment and tactics best suited for aerial anti - submarine warfare . It was based at Langley Field , Virginia throughout its existence , and equipped with B - 17 , B - 18 , and B - 24 aircraft . It was disbanded on 20 April 1943 , but was reconstituted in 1985 as the 365th Electronic Warfare Group . History . The 1st Search Attack Group tested equipment and developed techniques and tactics for aerial use against submarines and surface craft . It also helped develop an effective depth bomb with shallow fuse settings for about 25 feet . Eventually , the Americans and British developed a blunt depth bomb that sank slowly and exploded at the desired depth to destroy a submarine . This depth bomb became standard in early 1943 . Perhaps the most important task of the 1st Sea Search Attack Group was to develop techniques for using Airborne Surface Vessel Detection ( ASV ) radar to find surfaced submarines . The radar that eventually went into production was 10 - centimeter wave equipment , known as ASV10 . By February 1943 , a skilled radar operator could identify surfaced submarines at more than 40 miles ( 64 km ) and even the conning tower of a boat running decks awash at 15 to 30 miles ( 24 to 48 km ) . Initially the ASV10 radar sets were placed on Douglas B - 18 Bolo medium bomber s flying antisubmarine patrols . Some 90 B - 18 ' s carried the equipment by the end of June 1942 , but the Allies needed the microwave radar on the Consolidated B - 24 Liberator , which had a much longer range than the B - 18 . Equipped with auxiliary fuel tanks , microwave radar , and a powerful searchlight , the B - 24 long range bomber was ideal for extended antisubmarine patrols . The USAAF outfitted its first two microwave radar equipped B - 24 ' s in September 1942 , and the 3d Search Attack Squadron was equipped with B - 24s in December 1943 . Using the B - 18 ' s and B - 24 ' s assigned to it , the 1st SeaSearch Attack Group trained combat crews in the tactical employment of new equipment . In general , the USAAF employed three broad types of anti submarine operations : ( 1 ) routine aerial patrol of waters in which an enemy threat might exist ; ( 2 ) air escort or coverage of convoys within range of land based aircraft ; and ( 3 ) intensive patrol of an area in which one or more submarines had been spotted , an operation the AAF termed a " killer hunt " ( in contrast to the U . S . Navy expression " hunter killer " ) . At various times , each of these operational tactics had its place in the antisubmarine war . However , World War II era radar sets were notoriously unreliable and difficult to maintain , and scientists assigned to the 1st Sea Search Attack Group found much of their time consumed by seminars in the field on basic functions and maintenance of equipment . Consequently , the AAF established a squadron of the group to train ground personnel in its proper maintenance . With the redesignation of the Army Air Forces Antisubmarine Command as I Bomber Command , the group became concerned primarily with radar training for combat crews until its disbanding in April 1944 .