1943 the Eighth expanded in size to 16 groups of B-17s and 4 of B-24s, and by the following June would grow to 39 groups. The table of organization and equipment for heavy bombardment groups was increased from 35 to 62 planes with a huge influx of new bombers beginning in the autumn of 1943, and the use of composite groups was discontinued as many groups flew two group boxes on a single mission. The 54-plane wing combat box used by the Eighth's B-17s required both practice and discipline to maintain formation. Turbulence from leading bombers added to the difficulty of maintaining formation. The 54-plane box is capable of fielding upwards of 700 heavy calibre defensive machine guns in total to serve as a formidable defense against fighters, however. As flak became the greater threat in May 1944, the 36-plane box was resurrected in a much looser formation and became the standard through the remainder of the war except on days when significant fighter opposition was anticipated. Group combat box revisions In October 1943 the first radar-guided Pathfinder group began operations, bringing about a need for a compact 36-plane group formation to optimize bombing performance in adverse weather conditions. This was done initially by doubling the number of three-plane elements in a squadron formation from two to four, and placing all three planes within an element at the same altitude to avoid collisions. LeMay, who had been promoted to command of the 3rd Bomb Division, devised this diamond-shaped 12-plane combat box and preferred it over others, so that in August 1944 when he took command of Operation Matterhorn in India he adopted it as the basic formation for B-29 Superfortresses. A variation of the formation using four 9-plane squadrons in a diamond formation was developed to compress the bombing pattern further. Wing boxes followed each other in trail, and the formation was easier for escorts to protect. However, the close stagger of the four-squadron 36-plane was difficult to maintain, and increased the likelihood of a bomber flying at the bottom of the box being struck by bombs dropped from a higher plane. In visual bombing situations the revised 36-plane box eliminated the lowest squadron to lessen the possibility. Although the 36- and 27-bomber group combat box became standard for most of 1944, a diamond-shaped formation of four 10-plane squadrons was developed for B-24s of both the Eighth and Fifteenth Air