Combat box The Combat Box was a tactical formation used by heavy ( strategic ) bombers of the U . S . Army Air Force s during World War II . The combat box was also referred to as a " staggered formation " . Its defensive purpose was in massing the firepower of the bombers ' guns , while offensively it concentrated the release of bombs on a target . Initially formations were created in keeping with the pre - war Air Corps doctrine that massed bombers could attack and destroy targets in daylight without fighter escort , relying on interlocking fire from their defensive machine gun s , almost exclusively the Browning M2 . 50 - calibre gun . However the use of high altitudes by USAAF bombers resulted in factors that demanded a tighter bomb pattern and the combat box continued in use even after the advent of fighter escort largely mitigated the threat of fighter interception . Creation of the concept is credited to Colonel Curtis E . LeMay , commander of the 305th Bombardment Group in England . However the Eighth Air Force had been experimenting with different tactical formations since its first bombing mission on 17 August 1942 , several of which were also known as " boxes . " LeMay ' s group did create the " Javelin Down " combat box in December 1942 , and that formation became the basis for the numerous variations of combat boxes that followed . The practice of referring to a concentrated formation as a " box " was the result of diagramming formations in plan , profile and front elevation views , positioning each individual bomber in an invisible boxlike area . The evolution of Eighth Air Force formations . 1942 experiments . The first ten missions of the Eighth Air Force from England in August 1942 were shallow penetrations of France strongly supported by Royal Air Force Spitfire fighter escorts . B - 17 Flying Fortress es flew in six - plane squadrons with two to four miles between squadrons , to avoid mid - air collisions between the inexperienced crews . Although unable to support each other , the six - plane squadrons had the virtues of simplicity and ease of control . The bombers within a squadron were stacked at three altitudes with approximately between the highest and lowest , and except for the lead pair , were not in mutually supporting elements . As missions grew larger in size , deeper in penetration , and faced increasingly effective defenders , the AAF recognized that more compact formations were needed and returned to the three - aircraft vee formation that had been standard before the war . Squadrons consisted of three such vees , all flying at the same altitude , with two such squadrons in a group formation , the second higher , trailing , and staggered to the right . The entire formation was high , deep , and nearly across . It proved cumbersome to maneuver , as did a 36 - plane alternative , and left many bomber gunners with restricted fields of fire . The original two heavy bomb groups of the Eighth Air Force transferred to North Africa and were replaced in October and November by four new groups of B - 17s ( the 306th , 91st , 303rd , and 305th groups ) , and two of B - 24 Liberator s ( 44th and 93rd BGs ) , each of which experimented with its own formations . Their early missions included numerous mechanical turnbacks ( " aborts " ) which hampered development of effective schemes . Between November 1942 and the end of the war various configurations of the combat box were adopted to meet changing conditions , particularly changed German tactics that stressed head - on attacks against the weak forward firepower of the bombers . The 305th BG innovated the 18 - aircraft " Javelin Down " formation , which stacked planes within an element and squadrons within a group downwards in the direction of the sun . This aided gunners on the higher aircraft in seeing lower aircraft without being blinded by glare . In the front elevation the formation resembled a set of stairs , but in profile and plan resembled a spear point . Unlike earlier group formations in which the lead bomber had flown in the lowest position , it now was placed in the center of the formation vertically . The 305th successfully tested the formation on a December 6 , 1942 mission to Lille , and it was immediately adopted by the other three B - 17 groups . The 305th soon developed a more compact staggered formation that stacked elements downward in one direction , but stacked squadrons upward in the opposite direction . A third element of three bombers was added to the 18 - plane box , placed in the most exposed squadron for additional support . This resulted in a 21 - plane wedge - shaped configuration that was adopted by all groups on January 13 , 1943 , and remained standard through September 1943 . Wing boxes . Although the combat box was initially designed around a group of airplanes , it was expanded to include a formation of three groups flying together as a " combat wing " , all of which were based on the same triangular design of a leading bomber ( or grouping of bombers ) in the center , and two bombers ( or groupings ) immediately behind in a vee shape , with one at an altitude above and one below the center in close proximity for mutual defense . The new combat boxes continued to be used , but groups were placed in a horizontal column and stacked at increasing altitude to decrease their vulnerability to attack . This resulted in the rear formations lagging behind which impacted both defensive tactics and bombing performance . The wing box , a 54 - plane formation ( basically three 18 - plane boxes stacked in a similar fashion to the group box ) , evolved from a need to provide defensive fire against head - on attacks . The formations were stacked so that while squadrons were stacked away from the sun on missions , groups were stacked in the opposite direction , making for a more compact wing box . Because the Eighth AF had only four B - 17 units until May 1943 , composite groups were formed by combining squadrons from different groups , or a fourth group was added to the wing box to form a diamond shaped box . The latter was flown in a trailing position behind the wing and proved susceptible to Luftwaffe tactics of attacking the extremities of formations . The wing box was often spread vertically , deep , and across and was difficult to maintain . The most serious disadavantage of the wing box was that the lowermost and uppermost elements , trailing at the end of the formation , had the least mutual protection . An additional risk was that of an aircraft being struck by falling bombs if it strayed in the box ( see image ) : " Directly below us ( on 19 May 1944 to Berlin in B - 17G 42 - 102411 ) in the path of our falling bombs was a B - 17 out of position . Later pictures show a B - 17 having his left stablizer shorn off by a five hundred - pound bomb dropped from above . That plane went into a steep dive , out of control , and was lost . As mentioned before , the bombs had to fall about five hundred feet or more before the protective vane spun off to leave the bomb armed . " — 303rd BG pilot Richard Riley Johnson In the summer of 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 served as a defense against fighters , however , and 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 Superfortress es . 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 Force . During the winter of 1944 - 45 , minimizing losses to flak became a priority . The 27 - plane box became standard for B - 17s for all of 1945 , spread more laterally to avoid catastrophic damage to the formation from a single shell burst . At the same time wingmen flew more forward on element leaders , creating a box that was stacked vertically , from front to back , and laterally . This final variation presented flak gunners with a small target , produced excellent bomb patterns , and was both easy to fly and control . B - 24 combat boxes . B - 24s of the 2nd Air Division , more difficult than B - 17s to fly in formation at high altitudes and with more restricted cockpit visibility , used a variation of the 27 - plane group box . One element of each squadron ( normally the uppermost in the middle / lead and high / right squadrons , and lowermost in the low / left squadron ) was moved to the outside of the formation so that it was abreast of the trailing element . This produced a line formation that was wide and vertically , but only deep , reducing the time over target significantly . The 96th Combat Bomb Wing further refined the formation during its bomb runs by shifting the lead squadron into the highest position , the second squadron overlapping it in trail and lower , and the third squadron in file behind the second and another 150 feet lower . This produced devastatingly accurate bombing results in the last months of the war . Fifteenth Air Force formations . The Fifteenth Air Force , consisting of a preponderance of B - 24 groups flying at altitudes or more lower than those flown by the B - 17 groups in the Eighth Air Force , employed a larger group box during the period of December 1943 to July 1944 . Called the " six - box formation " , it consisted of forty aircraft , with the group divided into two units of twenty B - 24s , one behind the other , and each unit consisted of three squadron boxes . The center squadron ( known as Able Box ) of the first unit was a composite formation of six aircraft containing the group leader , with the deputy leader flying on its wing . The other four aircraft of Able Box were from the two squadrons assigned to the unit for that mission , with the six bombers formed in two vee formation s in trail and stepped lower in altitude . On each side of the lead squadron were seven - bomber boxes called Baker Box ( to the right ) and Charlie Box ( to the left ) , each box made up of bombers of one squadron , also in vees of three , with one additional bomber flying in the slot of the center rear ( sixth position ) of each squadron box , and known as " Tail - end Charlie . " This position was usually flown by the least experienced crew in the squadron and was vulnerable to fighter attack , so perilous that it was commonly called the " coffin corner " . The second unit of the group formation was configured identically , except that its boxes were named Dog , Easy , and Fox . Each position within a box was numbered , so that the group leader flew the Able One position while the Tail - end Charlie of the leftmost rear squadron flew Fox Seven . The second unit flew at an altitude approximately lower than the first unit . Because it was laterally wide , the six - box formation was not a compact formation , was cumbersome to fly , and thus was less efficient in bombing accuracy . The Fifteenth Air Force adopted the diamond formation during the summer of 1944 to increase its bombing accuracy , but this also had the negative consequences of increasing losses to flak . This formation reduced the number of boxes from six to four , each flying three 3 - plane elements with a Tail - end Charlie . As with the six - box formation , the trailing elements were stacked downward from the high leader , and the Tail - end Charlie of the fourth box ( Dog Ten ) was often referred to as " the Purple Heart position " . The four - box formation proved easier to assemble and organize , provided a tight bomb pattern , and concentrated defensive firepower against fighter attacks .