Part Il-C Planning!;

The following question was submitted to 26TH INF. DIV.: "This mission (counter-flak) ground force units: should always be fired in coordination with close med­ To what extent do you consider it practicable to ium bomber missions. This usually takes place before divert artillery to counter-flakfire for the purpose of assur­ troops have left their line of departure and artillery ing more effective air bombing in conjunction with can then best be spared by the Infantry battalions. assault operations? Even as the assault progresses, counter-flak fire can Their comments are summarized in these be delivered in coordination with fighter-bomber replies: attacks by at least one Divisional artillery battalion. If battalions are displacing, if the TAI-O does not TWELFTH ARMY GROUP: "It is considered have telephone or voice radio communication with practicable, and advisable, to divert artillery to coun­ Division Artillery FDC and if the target is on a flank ter-flak fire to the limit of ammunition supply, and, and the guns cannot lay on the flak concentrations in the opinion of the Corps commander, to the extent there without shifting trails, counter-flak missions which it can be spared from support of the advancing may be difficult to work out without commiting ar­ troops. Artillery, a supporting arm, in such a role is tillery urgently needed for close Infantry support. performing a dual function of assisting the air forces, Corps Artillery should then be called for by the and reducing opposition to the ground by destroying squadron leader over R/T." dual purpose weapons." 87TH INF. DIV.: "From the aspect of obtaining THIRD ARMY: "We have had sufficient artillery accurate bombing by fighter-bombers, some counter- and cooperation from artillery commanders to en­ flak fire by Division Artillery is highly desirable, but able us to fire counter-flak fire on all known enemy this Division has often encountered the factor which flak and any unknown positions picked up during the would mean the shifting of trails by a battery of Ar­ mission. The period during which the aircraft are in tillery if heavy counter-flak fire was desired. As this the area is usually of short duration. Ammunition disrupts the Artillery fire plan in support of the ground supply has at times been somewhat short particularly troops, from the ground forces aspect, this would when a very large flight of bombers needed protec­ seriously impede the progress of the troops being tion over a longer period." supported and have a tendency to partly nullify the NINTH ARMY: "Diversion of artillery for coun­ effects of bombing and strafing in support of those ter-flak" is not an altogether correct term because same troops." during the advance from the Roer to the Rhine, it was frequently the case that fire on ground forces was 9TH INF. DIV.: "It is practical to divert division largely from enemy anti-aircraft artillery. When this artillery 100% to counter-flak missions during air condition prevails the normal counter-battery fires attacks. Fifteen minutes notice should be given to of the artillery can, to a certain extent, be coordinated alert artillery. It must be understood that counter- so as to fire the counter-flak — counter-battery fires battery missions only neutralize the enemy batteries; simultaneously, and when desired by the cooperating they do not often destroy them." aircraft." 10TH ARMD. DIV.: "In the usual tactical em­ V CORPS ARTILLERY: "The use of artillery for ployment of an Armored Division on a wide front counter-flak fire is a very important mission. It is not employing many Task Forces and small Teams it is a diversion. Consistent with artillery ammunition considered impractical to divert Artillery to counter- allowances, fire possibilities and the number and loca­ flak fire.Onl y when the Armored Division is employed tions of the enemy flak installations, it is practicable in a narrow divisional front is it practical to divert to use all artillery within a sector for counter-flak Artillery to counter-flak fire." fire for a limited period of time. Certain artillery units 3RD INF. DIV.: "It is felt when enemy AA is pre­ can readily be designated to maintain sustained neu­ sent in a target area to any degree of organization, tralization, should that be necessary." that artillery should fire counter-flak fire if any of the XVIII A/B CORPS: "It is practicable to divert AA positions are known. It is believed this assures artillery to counter-flak fire for the purpose of assur­ much more effective bombing and is a definite aid ing more effective air bombing in conjunction with to morale of the pilots and in gaining their coopera­ assault operations under certain circumstances. Ar­ tion." tillery fire, to be effective must: {a) Have a specific target. FIRST FRENCH ARMY: "It is difficult to give the number of artillery pieces which can have their (b) Be fired simultaneously with arrival of air­ usual missions eliminated in preference to counter- craft over area to be fired upon. battery against enemy flak. The question depends upon (c) Be advised of any change in the time over the result which is desired within a minimum period target in order for (b) above to be possible. of time. (100 tons of bombs can be dropped in one (d) Not fire blindly into an area designated as minute by a formation of 50 Marauders, whereas to the line of flight of the aircraft as this is a waste of obtain similar material results, concentration of fire artillery ammunition;" i by 100 155 mm batteries would be required.) In 358 Part Il-C Communications short, if decisive results are expected from an aerial TACs and Bombardment Division Headquarters, attack, it must be effective and must therefore not be while primary communications circuits of 12th Army unduly hampered by enemy flak. In this case, the Group extended forward to the subordinate corps. amount of means to be loaned, and for a short time Therefore, as the headquarters moved forward, the only, to counter-battery against the enemy flak can communication lines of the Air Force Headquarters be considerable. On a lesser scale, counter-battery became longer, while those of the Army Group were fire can be employed to facilitate close support fighter- being shortened. bomber attacks in a heavily defended area. In several instances, First French Army Flak batteries were suc­ After the temporary stabilization of the front cessfully used for counter-battery in coordination in the Siegfried Line, Ninth Air Force Headquarters with medium bomber attacks on the Chalampe (Adv) was able to maintain close contact with 12th Bridge." Army Group (TAC) Headquarters through the ex­ tensive use of VHF/FM radio equipment, which was XV CORPS: "Whenever the location of hostile available at that time in greater quantities than pre­ flak positions are in the vicinity of the target to be viously. Radio circuits were supplemented by wire attacked by fighter-bombers, or on the path to be facilities as rapidly as the latter could be constructed. followed by medium supporting the Corps, Corps When it became necessary for advanced headquarters artillery normally fires counter-battery missions just to operate from a new site on fewer wire circuits prior to arrival of the aircraft, and during the attack. than were required to meet the minimum opera­ For example: when fighter-bombers were attacking tional requirements, a speech and teleprinter switch Bitche and Camp de Bitche, friendly artillery was was established at the previous headquarters site and successful in neutralizing hostile AA positions. When was maintained in operation until static wire circuit medium bombers were attacking targets in the St. requirements could be extended forward to the new Wendel and St. Ingbert area, counter-battery on AAA site. positions in and around Saarbrucken completely si­ lenced the hostile AAA positions. On several oc­ Substantially the same situation existed in the casions, medium bombers reported receiving no flak, case of the Tactical Air Commands which, when although many hostile AAA guns were located in that moved forward in keeping with their associated Army Headquarters, were extending the line of com­ area. munications to the rearward airfields. In siting the 2. COMMUNICATIONS AND CONTROL CHANNELS. headquarters, consideration was necessarily given to the operating requirements of the large amount of a. COMMUNICATIONS. VHF and FM equipment located at command head­ (1) General Conditions: Air Force Headquarters quarters. Since FM equipment operates in the VHF was divided normally during the operational phases range, it is necessary that the FM site be sufficiently into two echelons. Advanced headquarters comprised high to permit line of sight transmission to the next a small operational group of personnel required to station. It is necessary, therefore, that a suitable hill conduct the combat operations and main headquar­ or other high ground be located within five miles of ters comprised the remainder of the personnel and the headquarters. In addition, the headquarters VHF ancillary units. Since the function of main head­ and FM sites should be at least four miles from any quarters was primarily administrative, its communi­ other large concentration of VHF or FM equipment, cations problems are not pertinent to this report. and at least ten miles from any radar installation, due to interference. The headquarters of the Tactical Air Commands and the 9th Bombardment Division were also divided (2) Axis of Communication: Prior to D-Day, an into an advanced and main echelon during periods of agreement was reached by the Chief Signal Officer, rapid forward movement. During static periods these 12th Army Group, and the Director of Communica­ headquarters were consolidated, if practicable, for tions, Ninth Air Force, to establish a Joint Wire improved efficiency. Group. This group was charged with determining a joint axis of communication and to provide the long- Siting Headquarters: Air Force Headquarters lines wire requirements of both units. The Joint (Adv) were sited close to Army Group Tactical Head­ Wire Group consisting of air and ground units, a pool quarters (operational headquarters) to facilitate the of troops, engineering and staff personnel of Army planning and coordination of the air effort with re­ Group and Air Force signal sections, operated under spect to the Army Group mission. During the period joint control for the purpose of planning, engineering, of rapid advances prior to stabilization of the front constructing, and maintaining the long-lines wire at the Siegfried Line, Ninth Air Force Headquarters requirements of both those units. (Adv) was unable to move forward as rapidly as Army The Joint Wire Group proved eminently satis­ Group (TAC) Headquarters due to communications factory to the Air Forces. Whereas approximately difficulties, and the two headquarters became sepa­ half of all long-line circuits are required to meet Air rated. The primary communications circuits of the Force needs, and the remainder to meet the combined Ninth Air Force extended to rearward areas, to the requirements of ground forces, service forces, and 359 Part lljC Communications miscellaneous agencies, the troops, staff and engineer­ Longlines toll circuits were provided pri­ ing personnel available to the Air Force are approxi­ marily through utilization of rehabilitated German mately half of those available to the Ground Forces. and civilian underground cables. When the battle The pooling of all facilities and joint provision of situation was sufficiently stabilized, the military con­ requirements avoided duplication of effort on the part structed open wire leads were used to a large extent of separate agencies and made it possible to provide to provide toll circuits, but normally this construc­ facilities which would normally be beyond the ability tion was too slow during rapid advances to permit of any one agency to provide. open wire leads to be used as a primary means of Axis of communications were selected after wire communication. Some use was made of re­ considering the following factors: habilitated civilian open wire circuits, but generally this type of toll facility did not yield sufficient quan­ a. Principal routes of captured main toll cables. tities of circuits for the amount of work expended b. Direction of advance of the Army Group. to be efficient. c. Location of the Army exerting the main effort. W/T radio nets were provided for command d. Ultimate objective of the Army Group. administration, G-2 air liaison, and G-3 liaison. The foregoing principles relating to the Air Extensive use was made of VHM/FM radio Force-Army Group axis of communications, apply links. AN/TRC-1 equipment was introduced to the equally at the Tactical Air Command and Army level. Air Force prior to D-Day, and the first tactical use of The selection of the axis of communication was a joint the equipment was made in providing cross-channel problem, solved by mutual decision on a common radio telephone and speech circuits which became axis. An influencing factor in the case of the TACs operational as early as D plus 4. Use of this equip­ is the location of airfield clutches, and communica­ ment proved so successful that additional units were tions between the latter and command headquarters. secured as rapidly as they could be procured from the In practically every case, with the exception of the United States. When hostilities ceased, Headquarters initial axis on the beachhead, the axis of communi­ Ninth Air Force was employing 8-1/4-100 mile cations was based on knowledge and employment of systems of AN/TRC-1 radio equipment covering a existing French, Belgian, and German underground total of 1,375 circuit miles. cable facilities, which were exploited to the maxi­ (b) Communications at Tactical Air Command mum. Headquarters consisted of the following: (3) Communication Facilities: (i) Admin - Ops Command Communication. {a) The following communications links were Wire: command to switching center — a minimum found satisfactory for the operational requirements of of three speech and four teleprinter; switch to each Advanced Headquarters, Ninth Air Force: group of separate squadron — three speech, three teleprinter circuits. Radio: VHF, FM radiotelephone Landline Radio and telegraph — one radio circuit to each fighter Distant Termination Speech Printer Speech Printer group and separate squadron which with CF-1 carrier equipment provides one teleprinter, two speech and Headquarters, Ninth Air Force 3 2 2 2 one engineering channel; radiotelegraph — organized 9th Air Division 2 2 2 2 into two nets of three groups each and the third net IX Tactical Air Command 2 2 2 2 XIX Tactical Air Command 2 2 2 2 for working airdrome squadrons and separate squad­ XXIX Tactical Air Command 2 2 2 2 rons. First Tactical Air Force (Prov) 1 1 2 2 "Roadbed" Advanced 2 — — — (ii) Air Cooperation Communications. Wire: "Eagle" TAC 5 1 — — one teleprinter circuit to each Corps Tactical Air Co­ "Pinetree" 1 1 operation Party; Radio: radiotelegraphy — the nets 2TAF 1 1 were so organized as to include a corps headquarters SHAEF Air 1 1 and the divisions of a corps with the NCS located All local signal equipment for advanced head­ at the Tactical Air Command Headquarters adjacent quarters was completely mobilized by mounting this to Combat Ops. equipment in K-53 vans and K-52 trailers. Initially (iii) Fighter Control Communications. Wire: only one complete set of equipment was mobilized, three speech and one teleprinter circuit were required including message center, cryptographic facilities, between the FCC and a Forward Director Post; telephone switchboard, carrier equipment, telephone five speech and one teleprinter circuit from the main frame and test board, teletype switchboard and FCC to the Microwave Early Warning (MEW) radar local machines, autocode equipment, radio receivers, installation; one each admin, speech circuit between and radio repair equipment. As operations progressed, the Signal AW Battalion Headquarters and Command, it was found necessary to have duplicate sets of mobile the FDP, and the MEW Stations; tie lines between the equipment in order to permit leapfrogging of the Command telephone switchboard and the FCC as headquarters. determined by current ops traffic levels. Radio: VHF

' :. • r?si i •;:»• •„ 360 329 lENTCfl OV

JOKLLC NMMIIWCATE* HMMK I

GUOCR M.IQUE

^ MNTM tOt

KV «0V.

2TAI

JOCBL. vwtfl MMgrniflfT LJMt « w iif«f «y

O O |WNTH

FMNMFIMT FO

T

j VCMUN T £

JtJL

O O , T-tO

ON MMW V

FOOTBALL "5v SPITF«£ 6AN6MMYBLUE ADV.

361^62 Part Il-C Communications

• AIR COOPERATION COMMUNICATIONS NETS

ARMY CORPS INF. DIV. I a DIVISION ARMD. DIV. I ARTILLERY TASK FORCE I ADJUSTMENT

TACTICAL G-3 CORPS AIR AIR PARTY

XXX xxxx TACTICAL COMBINED AIR ARMY OPS COMMAND

GROUND FORCE TELEPHONE GROUND FORCE TELEPRINTER AIR FORCE TELEPRINTER GROUND FORCE RADIO AIR FORCE RADIO .-» _

Figure 86 — IX TAC-First Army Air Cooperation Communications 363 Part Il-C Communications

IX TAC-FIRST U.S. ARMY AIR COOPERATION COMMUNICATIONS SYSTEM­

XXX XXX

G-3 AIR G-3

!XXXX G-3 A-3 COMBAT OPS

1 COMBINED OPS

9 AF 12 AGP

ill cto GLO 7

AIR UNIT GROUND UNIT

COMMUNICATIONS GROUND COMMUNICATIONS (TAC) (ARMY) TELEPHONE TELEPHONE TELEPRINTER RADIO RADIO

Figure 87 — Air Cooperation Communications Nets

364 Part Il-C Communications

LJ U cr O LL. 1­ cr D U ^. i MA Y CI R H Z O Z u. o Q V) < < (f) i cr id H cr D O Q U I

azi I­ •a: z

ly­

taoc

OO-IW — « <• CD M HSffi UIUt-h- KluU I-UZ3 CC

OJ UJ I 5

3651 Part Il-C Communications

R/T air-ground communications at the FCC — 12 (d) Group Communications in a Tactical Air channels for the control of aircraft; VHF, FM, FCC Command: An average of 8 trunk and 50 extension to FDP — two circuits (push-to-talk), and FCC to circuits plus those direct circuits necessary for com­ MEW — two speech and one teleprinter. Mobile bat operations were normally provided. The average Equipment: telephone toll test van, telephone and tele­ installation used the following approximate amount type trailers, and carrier trailers were employed very °^w * re and cable: successfully. Spiral four 5,000 feet Five-pair cable 20,000 feet (IV) W/T Radio Nets: two nets from com­ W-110-B 4 miles mand to groups; one net with AF Hq (Adv); one net W T radio nets did no t with AF Hq (Main); one net with continental Flying / J operate as well as sh u d be ex e ed S W&S duC lack f traffic Control at Le Bourget; one net to Southern France aQ°d *due to thPe "difficult- ™y encountere "\d in obtainin ° g a Recreational Center; three or four nets for air-ground clear channel of transmission. VHF nets were not coordination to Corps and their Divisions; one net used m Hnks wefe used tQ command and operated with two airdrome squadrons and night fighter squad­ vefy efficiently. A m i nimum o f difficulty was encoun­ ron; G-2 (Air) net to G-2 Air's at other Tactical Air tered with the air to ground channels and the VHF Command Headquarters; G-3 (Air) net to G-3 Air's at se t j n the airplane. other Tactical Air Command Headquarters; report­ Echelon operation could have been more ing link to IX Air Defense Command; one net between efficientl managed with the addition of vans for FCC, MEW, FDP, and Signal AW Bn Headquarters; mobmtv. Wit h the possible exception of telephone nets for special liaison units; receiving only on several switchboards, there was sufficient communications weather nets. equipment to carry on operations at a rear and an (v) VHF and FM Nets: There were no VHF advanced base. During such movements, however, personnel were strained to the maximum, and addi­ or FM nets used in a Tactical Air Command; FM radio tion of links were operated between headquarters and each to an danothe linemar nteletyp woulde operatorhave don, eswitchboar much to dreliev operae - fighter group, tactical reconnaissance group, separate ?' this situation. night fighter squadron, each MEW, each adjacent Tactical Air Command, each wing, Ninth Air Force (e) OPURG (Operational Urgent) Traffic: Rear, Advanced Headquarters, and Switching Center. Because of the failure of wire communication facili­ n the eriod of he rman Each of these links was capable of passing '« J™* P < °f breakthrough in the Eifel region, it was found necessary to adopt a three speech and four teletype circuits simultaneously r ...... communication procedure which would permit the when used in connection with carrier equipment. passage of operations orders over W/ T radio chan.

It was essential that Army and Air Force nel s T o accOmplish this a combat operations section units have separate FM frequency allotments evenly prepared condensed versions of their daily opera­ distributed throughout the available range, and it was tions orders, at the request of the signal officer, further required that adjacent Tactical Air Commands when wire and VHF/FM radio circuits were unstable. have separate allotments. During the early days of These condensed operations orders, or OPURG the campaign this was the biggest difficulty and caused messages as they were known, were then transmitted innumerable cases of blocked communications. Final­ to all subordinate headquarters over W/T radio links, usin ly, a satisfactory solution was worked out in which g break-in operations and a precedence that was the Army and Air Force allotment was subdivided over-riding over all other messages. This procedure, into two parts: A and B. Each alternate Tactical though simple, was very successful in expediting oper­ Air Command held the A allotment with B allotments ^rTweak*" ^ C ° mmuniCati° n drCUitS in between. This separated any two TACs holding the same allotments by the width of an Army front, and (/) Redline Messages: In order to provide a reduced interference. dependable and private means of communication be­ tween commanding generals of all echelons of the (»v) Atr-Ground Channels: There were no air- Nintfa Aif Forcej a system of RedUne messages was ground channels at Command Headquarters except established. It was required that all Redline messages at the Fighter Control Center. be cryptographed and be passed by the most expedi­ (c) Rehabilitation of Existing Facilities: In tious communication means available. Redline mes­ most instances the existing facilities on an airdrome sages were given a precedence second only to OPURG were so completely demolished as to preclude any messages. attempts at rehabilitation. Where it was possible, (4) Codes and Ciphers: In order to meet the con­ however, maximum use was made of existing facilities, tingencies of compromise of codes and ciphers, it i.e., under ground cables and open wire, and this pro­ was necessary to maintain a Ninth Air Force Head­ cedure speeded up the time required for completing quarters large stocks of reserve cryptographic ma­ an installation and saved on wire and cables. terial, broken down and packaged into units for each

366 Partll-C Communications

3RILLW0RK- 2 (GYPSY REAR) GRIlLWORK-3 ^4468

WILDHAWK-3 WILDHAWK-9 WIL0HAWK-I6 B-6024 H-4894 C'9959 94 2 r""-. 72 6 f ~_L-V: 75 0 Z'^^Z 7 92.2

MANNED AND OPERATED BY IX TACTICAL AIR COMMAND

MANNED ANO OPERATED BY XXIX TACTICAL AIR COMMAND

0 MANNED AND OPERATED BY 9T H BOMBARDMENT OIVISION (M)

0 MANNED AND OPERATED BY IX AIR FORCE SERVICE COMMAND

© MAMNED AND OPERATED BY FIRST TACTICAL AIR FORCE ( PROV )

© MANNED AND OPERATED BY SECOND TACTICAL AIR FORCE ( BR )

DIRECTION OF TRANSMISSION AND FREQUENCY IN MEGACYCLES

JHQ_N]NTH AiR FORCE VHF/FM RADIO LINKS DATE ­ AS OF 5 WAV 19 45

Figure 89 — VHF FM Radio links, Ninth Air Force 367-368 Part Il-C Communications

RESULTS OF_ 7AC, RECCE

6-2 AIR A/C FTR BOMB

RECCE OFF

FIGHTER AIR-GROUND CONTROL COOP PARTIES

PILOTS ~T^ / 160 SO 6LO S-2 6L0 SO S-3 SO

36 3 TAC/R 6P S-2 S-3 6-2 A-3 6-3 AIR i 1 —-­ FTR 6-2 ADJACENT ALL CONT ARMIES cam FTR BOMB

ALL X 0-2 ARTY CORPS 6-2 * NON- PREPLANNED MISSIONS. THE PILOT IS REQUESTED TO OBSERVE PARTICULAR POINTS WHILE IN AIR OVER AREA CORPS BRI6 ARTY ARTY

* THIS IS EMERGENCY ONLY, IN CASE OF TELETYPE FAILURE WHEN TELEPHONE FAIL*, COURIER IS USED.

Figure 90 — Results of TAC/R headquarters, so that distribution could be affected code. Had communications personnel been required rapidly. The existence of these stocks proved worth to encode a 9 or 10 page field order in such code, our while, for after three compromises of cryptographic aircraft would have been taking off for missions at materials in combat, reserve cryptographic systems dusk instead of dawn; however, this code was used were distributed and brought into effect within twen­ only when field orders were specifically written to be ty-four hours of the time that the compromise was de­ encoded in such a code and the very briefest in nature. clared. In past experiences of this command, the only logi­ cal solution was to use a high speed code or cipher It is believed that a code such as the combined for the transmission of such orders, as operations field code could easily be adaptable to any locality personnel required that full information be transmit­ by the distribution of a supplement suitable to the ted. As for using high grade codes such as SIGABA, locality of the organizations concerned. for encoding such traffic, it must be remembered The distribution of Combined W/T Authen­ that stations such as the MEW and FDP's, etc., also tication System should be limited to higher head­ received the field orders, and yet they were not au­ quarters that require combined communications thorized suitable high grade codes. In a theatre where and should not be distributed to such units as Signal transmission was largely by W/T, no code existed Aircraft Warning Battalions and Tactical Air Com­ that had the authorized distribution to handle such a munications Squadrons, as these units have only volume of operational traffic by radio. intercommunications and could easily use a Play- In the tactical air communications squadrons fair authentication. This policy was followed through­ in this theater, landline was used to a large extent out Army units and proved satisfactory in such units for passing traffic to air cooperation parties. In other as mentioned above. theaters this traffic would probably be by radio. The As far as special purpose codes were con­ M-209 has been declared by Signal Intelligence Divi­ cerned, it must be borne in mind that operations of sion, ETOUSA, to be a secure cipher for an indefinite an American air force did not adapt themselves readi­ period of time, when properly used. Yet in the early ly to the practices and methods of other Allied air stages of this campaign, higher headquarters doubted forces. A case in point would be the Operations Room the security of M-209 for such traffic as was passed 369 Part Il-C Communications over, the tactical air nets. A solution to this problem The system of control was common to each of the would have been the distribution of SIGABA to the Tactical Air Commands, and consisted of a correla­ Tactical Air Parties, although additional personnel tion of radar elements which formed a "control would have been required in the tactical air com­ group." This group comprised the following: munications squadrons. The primary consideration, (a) One Tactical Control Center (Fighter however, was that the efficiency and speed with which Control Center) traffic could be handled over these nets would be great­ ly increased, to say nothing of the increase in security. (b) One MEW (Micro-wave Early Warning SIGABA could have readily handled air support Radar) requests and messages indicating the acceptance and (c) Three Forward Director Posts refusal of targets, thus eliminating the air support {d) Three or four SCR-584s (Close Control control code, which had always limited the amount of Units) information to be transmitted and often required an (e) Four Direction Finding (Fixer) Stations additional message via M-209 to furnish more infor­ Included in the Control Group were the Signal mation to the Tactical Air Party Officer and his ground Air Warning Battalion, the Fighter Control Squad­ commander. rons, the Tactical Air Communications Squadron, (5) Comments from ground forces which are per­ a detachment of the AAA Brigade and other mis­ tinent to communications are as follows: cellaneous units. NINTH ARMY. "Some difficulty has been ex­ (1) Tactical Control Center: The Tactical Control perienced with failure of the VHF radio equipment Center was the principal element and nerve center used by the ground forces. This trouble apparently is of the control group through which airborne forma­ caused by rough handling. It is believed that develop­ tions and aircraft were controlled. The operations of ment should be continued to produce a more sturdy the other elements listed above, were directed from radio set for ground use." this point by the chief controller. The movements of all friendly and enemy aircraft as reported from 87TH INF DIV. "Channels of communications the Forward Observation Posts, FDPs, and MEW, in transmitting requests have been satisfactory as far were here displayed on a large scale map-board. The as fighter-bomber strikes are concerned; however, current operational status of the various tactical groups requests for medium bomber strikes are sometimes was maintained in visual form. The TCC also con­ not acknowledged — see (15). Regarding commu­ stitutes the principal center for monitoring and com­ nications between air and ground units — each Air municating with aircraft in flight, except such as had Support Party should have a 610 radio included in been turned over for control to the subordinate ele­ their T/O as they can then monitor and transmit ments of the control group. to Artillery liaison planes assigned to each Division Inasmuch as the Tactical Control Center had — these planes could be contacted to lead fighter- an up-to-date "air picture" of the entire Tactical Air bombers, for example, to an air target designated by Command area of responsibility, all TACs found it the ground forces." expedient to locate their Combat Operations Section 8 3RD INF DIV. "Improvement is desired in and Tactical Control Center immediately adjacent communications in regard to telephone lines. A sepa­ to each other This permitted the combat operations rate net from Division to Corps to higher echelon officer to take advantage of the current "air picture" would be better. Communications for heavy and and to advise the chief controller on the latest recce medium bombardment are not satisfactory. Time re­ flashes and operations information. In the Ninth Air quired is too long." Force, the TCC was located at TAC Headquarters and the Staff A-2 and A-3 personnel was integrated into 3RD INF DIV. "The present methods of com­ the Combat Ops Section. In the XII TAC, Combat munication in transmitting requests is satisfactory Ops and the TCC were located at 64th Fighter Wing as long as these communications are maintained. It is Hqs. and were less closely directed by TAC Hqs. necessary that a direct line be maintained between the Division and Corps Air Support Controllers. (2) MEW: The MEW is a radar set of extremely Corps Air Support, when moving, must maintain high power out-put and very short wavelength, giving communication with the Division Controllers in the it tremendous coverage and very good definition old location until communication has been estab­ (i.e., ability to pick out individual aircraft and locate lished in the new location. This has not been done in them accurately). In conjunction with its height- many instances and has caused a definite lapse in finding equipment it was able to provide complete air support availability." information as to range, azimuth, and altitude of air­ craft at ranges up to 200 miles. b. GROUND CONTROL OF AIRCRAFT: To take advantage of the information it ob­ The outstanding success which attended close-in tained, numerous indicator tubes were provided. Half cooperation by fighter-bombers and other aircraft, of these tubes, known as "B-Scans", were watched by was largely due to development of the technique for observers who are allotted certain sectors and re­ the navigational control of aircraft by radar;\ ported to the Tactical Control Center information

370 Part Il-C Communications

Elements of the 555th Signal Aircraft Warning Battalion fit together in a pattern like this. The MEW site, heart of the control setup, is usually within 10-30 miles of the front L/W REPORTING lines. Tactical missions can be directed from there, the 2 RADAR AN/TPS-3 Forward Director Posts and the 3 SCR-584 control centers

FORWARD DIRECTOR POST SCR-584 CONTROL AMES TYPE 15 8 22

(2) D/F D/F FIXER 3 UNITS

TELEPHONE TO FIGHTER WING AND GROUP M.E STATION FIGHTER CONTROL SCR-584 CENTER CONTROL T(io)

HQ. REPORTING RADAR UNIT FORWARD AMES TYPE SCR-584 DIRECTOR POST II 8 15 CONTROL AMES TYPE 15 8 22

L/W REPORTING RADAR CONTROL AN/TPS—3 REPORTING

X GROUND TO AIR (VHF)

Figure 91 — MEW Control and Reporting Links 371 Part Il-C Communications

on all aircraft in their sector. The remaining indicator was unusually difficult due to clouds, camouflage, tubes, known as PPI tubes, were manned by con­ or the small size of the target. This feature was ex­ trollers. tremely valuable on close cooperation missions where A formation engaged in close cooperation, de­ improper identification of a target might have re­ signated by the TCC for control by the MEW, was sulted in casualties to friendly troops. This highly tracked on one of the PPI tubes from the moment accurate navigational aid was also very effectively it appeared above its airfield, until ready to land. For employed for the control of night intruder missions, the purpose of identifying the various formations, a night photography missions, day photographic and D/F Fixer Station was located at or near each radar visual reconnaissance missions. site, including the MEW, and bearings were taken on With considerable practice and the develop­ all VHF aircraft transmissions. The bearings thus ment of new technique, the accuracy of SCR-584 blind derived were then correlated with the "Blips" on the bombing gradually improved to the point where PPI tube. When controlling a formation, the MEW average accuracies on the order of 400 yards could could furnish the formation leader with information, be realized. While this was not as accurate as original­ such as the following: ly anticipated, it could be used as a blind bombing (a) Course and distance to target. aid on marshalling yards and large targets. It is ex­ pected that, with the new type plotting equipment, (b) Position in relation to friendly troops. the accuracy can be further improved. (c) Position in relation to bomb line. In conducting a mission, it was necessary that (d) Warning of other aircraft in the vicinity. the formation rendezvous over an indicated point, at (e) Vectoring for interception of hostile air­ given altitude. The lead plane then would take sta­ craft, by day or night. tion about five hundred feet ahead of the formation. (/) Location of targets reported by the flight. When the SCR-584 had "locked-on" the lead plane, the pilot was notified to proceed. Enroute, he could (g) Relative positions of bomber and escort take evasive action to avoid flak or make other diver­ formations. sions from the course; the position of the plane, how­ (h) Vectoring to exact position for contact ever, was at all times indicated to the Controller by with air cooperation party. moving spot of light projected on the underside of a (/') Vectoring to position for SCR-584 control. horizontal map of 1:50,000 or 1:100,000 scale. ( 3 ) Forward Director Posts: Th e Forward Director The SCR-584 attained its maximum useful­ Posts were radar sets similar to the MEW but smaller ness in static situation. During periods of rapid ad­ in size and of less range. They did not have as large a vances, its present comparatively short range pre­ number of indicators as the MEW, hence, while their vented its employment to best advantage because of function was similar to that of the latter, their capacity the necessity for frequent moves. and flexibility was limited. The FDP was used to in­ (5) Direction Finding, Homing, and Fixing Facili­ crease the radar coverage and to handle missions when ties: Each of the Tactical Air Commands operated a the MEW was handling a capacity effort or was off Direction Finder-Fixer Net of at least four stations the air for a move. Missions to be controlled by the connected to the Tactical Control Center by FM FDP were assigned by the TCC. radio. These fixers ordinarily stood by on the TAC (4) SCR-584 (Close Control Unit): The SCR-584 frequency. However, all stations were also equipped radar set, originally designated for tracking air­ with all Ninth Air Force frequencies and several craft in connection with the control of AAA fire, has Eighth Air Force and British crystals. Frequency been modified for use for guiding aircraft or forma­ changes could be made in thirty seconds. tions to pin-point targets. Fixes and bearings to base were S. O. P., and The set was highly mobile, and could be set only the volume of traffic handled was noteworthy. up in one hour. Its practical operating range was Maximum capacity was probably achieved in help­ originally limited to from 25 to 35 miles, but recent ing the Eighth Air Force, when, in the case of IX improvements using radar beacons in the aircraft TAC, seven hundred fixes and/or bearings were extended its range to 100 miles. taken on Eighth Air Force transmissions in a five hour period. The SCR-584, modified for close control, was originally introduced as a weapon for the control of Stations were sited on high ground to obtain blind bombing, either through the overcast or under maximum range, and successful fixes have been conditions of poor visibility. Initially, the results of obtained at distances exceeding 120 miles from the actual blind bombing missions were not encouraging. center of the net. However, from the first, the SCR-584 proved to be a (6) Communications: The Ground Observer Posts very excellent device for enabling the controller to and light warning radar were connected to FDPs by bring a flight over the correct target and put the FM radio, with high frequency WT standby. The FDPs leader in a position to deliver a visual attack, under were connected to the TCC by FM radio and tele­ conditions when locating and identifying the target phone. No serious difficulties were experienced in

372 Part Il-C Communications employing FM communications between the TCC variety of devices were employed, including AA bursts, and its subordinate control elements. barrage balloons, panels, buncher beacons, and an (7) Lead-In Aircraft: In cases where the target SCS-51 localizer transmitter. In addition to these was discovered by a tactical reconnaissance aircraft, marking devices, a VHF ground-air control station the controller intercepting the flash report advised was set up, and another channel was kept open for the chief controller who selected an airborne for­ communication between ground headquarters and mation for diversion if available in the vicinity. The VIII AF Headquarters. Only one instance was re­ controller then directed the reconnaissance aircraft to proceed to some prominent landmark where a ported of bombs falling behind our lines, and this rendezvous was effected with the fighter-bombers. was due to a mechanical failure in one plane. The reconnaissance aircraft then led the formation (2) Effectiveness of Marker Devices. to the target, indicating its precise location, if neces­ Panels: Luminous panels were only useful under sary by a strafing attack. conditions of good visibility and were also merely a An alternative procedure was to direct the fight­ precautionary measure. er-bombers to make contact with the reconnaissance Colored panels proved to be the most practical aircraft and arrange the rendezvous. means for identification of ground units and should L-5 aircraft, equipped with SCR-522 ^radios, have been displayed on all vehicles, gun positions, were used with notable success for leading fighter- and other forward elements within two miles of the bombers to a target located close to our front lines, front lines. They were particularly valuable for iden­ and for controlling their subsequent attack. In em­ tifying armored column spearheads. There appeared, ploying this method, an effort was made to maintain however, to be a reluctance in many cases to display a "Horsefly" airborne throughout the day, in contact panels, for fear that they might invite enemy air attack. with the corps or division TAPO. This aircraft, Throughout the campaign the chance of attack by flying at from 3000 to 4000 feet, was able to observe friendly fighters, due to mistaken identification, was enemy movement and spot pin-point targets without considerably greater than the danger of attack by difficulty from this comparatively low altitude. When enemy aircraft. an appropriate target was discovered, the latter was reported to the TAPO, who arranged over the air Efforts by the enemy to create confusion by cooperation net for a fighter-bomber attack. The employing captured panels were seldom successful, "Horsefly" then contacted the approaching formation due to the comparatively small number available to and led it to the target. Smoke bombs dropped with them. In cases where the formation leader doubted considerable accuracy from low altitudes, by the L-5, the authenticity of ground panels, they were instructed were frequently used to mark the target. to contact the Tactical Control Center as to the possi­ The presence of an observer, skilled in identifi­ bility of friendly forces being in the neighborhood. cation of friendly and enemy ground troops and A panel code was developed, which prescribed equipment, and familiar with the local ground situa­ change of panel colors from day to day. Yellow, tion, made it possible to attack targets close in front red, and white panels were displayed, either singly or of our forward positions without danger of mistake. in combination. Thus employed, the L-5 "Horsefly" constituted a Flares: Flares fired by lead aircraft to indicate superior air observation post and flying office for that the target had been definitely located, with ac­ the Air Controller. knowledging flares from following aircraft, proved to c. TACTICAL AND TECHNICAL AIDS FOR be an excellent precautionary measure. TARGET IDENTIFICATION. Orange smoke flares were provided for the (1) General: The need for a method of providing identification of friendly elements. They were not indication of a safety line for heavy and medium bomb­ a satisfactory substitute for panels, however, as an ers cooperating in close-in operations, short of which appreciable time was required to put the smoke in bombs should not be dropped, was emphasized by action, during which the planes passed beyond the the experience obtained at St. Lo (Operation "Co­ position. The orange smoke, moreover, tended to bra"). In this operation, which was the first instance attract artillery fire and were soon obscured by smoke in which heavy and medium bombers were employed and dust. in great strength close to our front lines, a number Smoke Marking of Targets: Colored smoke was of bombs were dropped as a result of errors in tactics used widely and with great success for pin-pointing or bombing technique. However, it was found that close-in targets for fighter-bombers. The formation the smoke and dust from the heavy bombing obscured was generally guided to the target area by radio and the reference line (St. Lo-Periers road), which marked navigational aids or identified the target area by refer­ the near side of the target area. ence to prominent local landmarks. When the air­ Following this experience, an elaborate mar­ craft were in position for attack, the colored smoke ker plan for heavy bomber participation was devised was laid down by artillery fire to mark the aiming and employed at Eschweiler (Operation "Q"). A point. 373 Part Il-C Communications

COMMUNICATIONS FOR CONTROL 4000 YDS. ESCHWEILER—16 NOVEMBER 1944

CLOSE SUPPORT FRONT LINE COMMUNICATIONS TEAM RELATIVE POSITION OF EQUIPMENT (ALL BOMBING BY GEE-H OR MICRO-H) MASTER AIR CONTROLLER

Figure 92 — Communications for Control, SCS-51

White phosphorus smoke proved to be the patterns with scope photographs of the actual inva best from the point of view of visibility, with red sion coast, the bombers were able to hit their narrow smoke as an alternative. However, green smoke was target with satisfactory results. effective when the ground was snow-covered. The enemy became very sensitive to this use of smoke and The coordination method was also the best for was prompt to fire colored smoke on our positions bombing through a complete overcast. A number of when he anticipated a fighter-bomber attack. To check points were chosen along the penetration route. avoid the danger of mistake, combinations of colored As the aircraft flew over each one, the H2X operator smoke were employed either pre-arranged, or as identified them in his scope and transmitted the data to requested by the formation leader. the bombardier who made the necessary adjustments in his bombsight. When the aircraft was about twelve Anti-aircraft Bursts: Colored AA burst at miles from the target the H2X operator transmitted 2000 feet below the bomber formation was the best a final check. Then the aircraft was moving toward the of the visual means. target along a definite track. The bombardier trans­ Smoke-lay ing Aircraft: Smoke laid by aircraft posed these computations into a dropping angle which was unreliable and involved the difficulty of co­ was set in the bombsight. When the indices met, the ordination and timing. It was not satisfactory. bombs released automatically. If a break in the (3) Technical Aids: The best technical aids were clouds occurred, a visual sighting at the last minute far superior to any of the visual aids mentioned above. was possible, and minor corrections could be made. H2X: H2X is airborne radar. It transmits high This was the technique used on D-Day. Eighteen frequency electrical impulses downward through a to thirty-six aircraft were flown abreast with the H2X revolving antenna. These impulses are reflected back aircraft in the center of the formation. H2X operators to the antenna by various objects on the earth. The carried maps and scope photographs of the invasion H2X set converts these reflected impulses into light coast. Long familiarization with vertical and scope patterns on the scope of the set. By matching these photographs of the English and French coast lines 374 Part Il-C Communications enabled them to identify the shipping and shore-line hitherto unobtainable. The beacon was placed parallel patterns in their H2X scopes. to the front lines, at the appropriate distance for safe­ The H2X scope was useless for most categories ty, in accordance with the altitude of the bombers. of close-in air cooperation targets. It was, however, When the aircraft passed the SCS-51 beam, as indi­ useful in special situations such as bombing from over cated by the change of colors on the indicator, they water towards a land target. In this case, the shore were certain that their bombs would strike beyond line was clearly indicated on the scope. the line which our troops had been withdrawn. The distance from the SCS-51 beam to the near side of the X-Band Beacons (BUPX).These small port- target area was usually announced at briefing. able beacons, used in conjunction with H2X, were excellent for marking the safety line. They could be Beacon Bombing Methods: The most widely placed rapidly where desired, and were thus valuable used technical aids for close-in cooperation bombing in a changing military situation. (This equipment was were the four beacon bombing methods: Shoran, not obtainable in the ETO). Gee-H, Micro-H and Oboe Mk II. Their comparative characteristics are listed in the Table 37. Buncher Beacons: These large, non-portable Characteristics which are shared by each have beacons were a fair means of demarcation of safety been omitted; for instance, their tactical application, lines. As they were subject to distortion of the beacon on specific operations, which is discussed thoroughly signal by enemy counter device, they could not be in Volume I. Each system was built for bombing relied upon. As target markers, they did not give an through overcast, and all could be used for navigation, accuracy such as that obtained with Gee-H and M-H air-ground cooperation, mapping etc. Range and fixers. coverage were essentially the same for all lines of SCS-51 (Localizer-Transmitter): This equip- sight from ground stations, or about 200 miles at ment, normally used for blind landing approach, as 2 5,000 ft. Also, the methods were alike in that they applied to the marking of the safety line for close-in each required about 2 hours of pre-flight computation cooperation missions provided a degree of safety before a mission.

TABLE 37: COMPARATIVE CHARACTERISTICS OF BEACON BOMBING METHODS

Shoran Gee-H Micro-H Oboe Mk II

METHOD Dual beacon system. 2 nor­ Dual beacon system. 2 bea­ Dual beacon system. 2 nor­ Dual interrogation of OF mal beacons on ground cons on ground. Ranging mal beacons on ground. transponder in plane. TRACKING: with ranging interrogator interrogator in plane. No Ranging with airborne Ranging interrogators on and computer in plane. computer. H2X; data can be fed to ground. Plane tracked in bombsight. Mk I has delay range and ground speed attachment on ground; from ground. Mk II, in plane. FLIGHT Automatic tie-in to PDI Oral directions to pilot. Oral directions to pilot or Aural indications to pilot, CONTROL: showing rate and displace- manual AFCE tie-in. (tone signals.) ment. PRESEN­ 3" J scope with 1, 10, 100 Normal Gee "A" scope. Normal beacon presenta­ Tracking from ground TATION: mile sweeps. Pip match­ Double trace and strobes. tion on PPI scope divided stations; no presentation ing. Circular trace. into 2 sectors. in plane. GROUND 2 beacon stations which 2 transmitting stations for 2 AN/CPN-6 beacons; 2 ranging interrogators EQUIP­ operate unattended. bombing, 3 for navigation; very little attendance re­ and control center; skilled MENT operate unattended. quired. ground crew needed. PLANES Medium bombers. Medium and heavies. Heavy bombers. Medium bombers. USED: SATURA­ 20 interrogating planes 5 interrogating planes per 50 interrogating planes 1 plane every 15 TION per pair of ground sta­ pair ground stations per pair of ground sta­ against 1 target, POINT: tions, attacking up to 20 attacking 5 targets. Any tions, attacking up to 50 targets. number for Gee naviga­ targets with Mk II, limited tion. number with Mk I. AIRBORNE Bombardier. Navigator or radar opera- Radar operator. Pilot and co-pilot. OPERATOR: tor. TRAINING 2 weeks for bombardier 2 or 3flights for navigator 4 flights for regular radar 10 hrs. in link trainer for FOR and pilot. or operator familar with operator. pilot. 10 hrs. in link. OPERATOR: Gee. OPERA­ First used by 12 th AF Dec. First 8th AF mission Feb. First combat mission for First U. S. mission Jan. TIONAL 1944 12thAF could equip 1944. Effectively used on Mk I Nov. 1944 by 8th 1944 by 8th AF. Later in AF. 5 beacons on Contin­ 9th AF (44 sets ofMk II). STATUS: 4 planes each in 3 groups D-day and against buzz- s 44 air and 9 ground sets bomb sites. ent, 4 in England. Mk II *' in 9th AF. operational 1 March 1945.

375 Part Il-C Communications

On the other hand, accuracy indications have MICRO-H: Due to the nature of the areas to be been omitted, not because accuracy was the same for bombed by overcast methods, target identification each, but for lack of an adequate basis of comparison. difficulties with standard H2X equipment increased. There were too many variables. Generally speaking, So a technique of overcast bombing was introduced their accuracy was somewhere between direct H2X to improve the accuracy of H2X. This improvement bombing at its best and visual, although Shoran has was called Micro-H. It applied the "cat and mouse" been demonstrated to be equal to or better than visual principle of Gee-H to the H2X scope. in some cases. Once airborne, the force navigated by Gee to These systems did not pose as substitutes for the Initial Point, about 35 miles from the target. H2X, which remained unchallenged for long range Here the navigator turned on his H2X scope to "bea­ radar bombing against strategic targets. Beacon bombing had a field of its own-short range precision con". Instantly the scope received pulses from two bombing of tactical targets, such as troop concentra­ Micro-H stations transmitting on assigned frequencies tions, supply dumps, and command posts, which could from installations near Namur, Belgium, and Verdun, not be resolved on a PPI scope. This type of bombing France. The ranges of these stations were represented became more and more important with the shrinkage by two bright white dots, both approximately equi­ of German territory. distant from the center of the scope. If they were not, GEE-H: Over the English Channel, navigators the navigator corrected the pilot's course accordingly on ships with Gee-H airborne equipment flicked on so that the aircraft moved along the Gee-H course their receivers and transmitters. Immediately the toward the start of the bomb run. transmitters sent out pulses which "triggered" or As in the case of Gee-H, Micro-H experts at actuated, all Gee-H ground stations within range of Eighth Air Force Headquarters computed a series of 200 miles. The answering pulses returned on another check points for the navigator with corresponding frequency to the Gee-H receiver in the plane where sighting angles for the bombardier. When the air­ they translated by the cathode ray tube into pips on craft began its bomb run about ten miles from the the scope. target the navigator set his first check point on the One of the pips represented the distance from scope in the form of a range circle. Then as the air­ the "cat" or range station; the other the distance from craft moved toward the target the two white dots the "mouse" or releasing station. First the navigator moved simultaneously toward the circumference of watched the "cat" pip. Each pilot was holding his the range circle. The moment they touched it the navi­ B-24 on a course along the arc of a circle cutting the gator warned the bombardier, "Check 1". Immediate­ target, and the center of that circle was the location ly the latter synchronized his bombsight to include of the "cat" station. If the B-24 got off course the the corresponding sighting angle. Subsequently, navigator corrected the pilot after checking the "cat" range. each check-point along the bomb run was synchron­ ized into the bomb-sight until the aircraft reached the The navigator flicked a switch on his scope. release point. Instantly the position of the "mouse" pip was cali­ brated in Gee-H units. Beside the navigator were a The original Micro-H technique had three series of pre-determined check points computed at inherent restrictions: range, target handling capacity, Eighth Air Force Headquarters by trained Gee-H and course. Only ranges within 180 miles of the bea­ experts. These check points were also in Gee-H units. cons were feasible, and because of the course, forces By comparing the calibrations on the scope with the could bomb but one target at a time, being limited data furnished by higher headquarters, the navigator to two avenues of approach — inbound and out­ could check his progress toward the warning point. bound. Where flak or wind direction threatened to Both the navigator and bombardier knew in interfere with the course, Micro-H was impracticable. advance that after the aircraft reached this final check­ (4) Comments: Suggestions from ground force point, a timed run would be necessary, at the end of units, on marker plans for delineating the safety which the bombs would be released. The length of line for bombing by medium and heavy bombers, this timed run was a figure in seconds computed by showed some difference of opinion, but this was the navigator from "warning period" tables based on probably due to a ground force point of view and the the true altitude, ground speed, and type of bomb. This unfamiliarity by some units with certain of the aids figure was transmitted to the bombardier. mentioned. As the B-24 approached the "warning point" TWELFTH ARMY GROUP. "Flak, panels, SCS­ the navigator kept his eye on the "mouse" pip. The 51, balloons and smoke have all been used success­ minute it reached the pre-determined range he called fully. All are dependent for effectiveness on weather to the bombardier, "Check!" Now the B-24 began its or mechanical perfection, but combinations of them timed run for the target. The bombardier carried a seem adequate. Balloons are too vulnerable to ene­ stop watch. At the completion of the timed run, he my fire, and if used repeatedly would surely be a released the bombs. giveaway of intentions." 376 Part Il-C Communications THIRD ARMY. "A line of colored flak was used d. SIGNAL INTELLIGENCE OR "Y" SERVICE. in the heavy bombardment of Metz Forts. No The establishment of Signals Intelligence or casualties were caused among friendly troops and the "Y" Service was attended with early difficulties. mission was highly successful. The medium bombers Authority was received in November 1943 for the have successfully and consistently attacked close-in organization of Signals Intercept Units and intensive targets on Third Army fronts by both visual and blind efforts were then made to procure equipment (much methods and there is much evidence to indicate that of which came from British sources) and personnel. improvement is constantly being made in safety equip­ Training was accomplished by placing the personnel ment." in operational positions with the extensive intercept organization maintained by the R. A. F. in the United NINTH ARMY. "Marker plans for delineating Kingdom. the safety line for bombing at the commencement of The 3rd Radio Squadron (Mobile), which came operation "Q" were effective. However, continued into existence as the unit serving the Ninth Air development along these lines is called for so that Force, was functionally divided into voice intercept the safety distance can be reduced to the bare mini­ and code intercept detachments. mum. Only by being as close as possible to the ob­ The final organization of the radio squadron jective can the ground forces close quickly on it and provided a Voice Intercept Detachment with each therefore gain full advantage of the strike made by Tactical Air Command in the field. An additional de­ medium or heavy bombers." tachment for the interception of German Air Force 1ST INF DIV. "Marking of front lines with code traffic operated directly under Headquarters, Ninth Air Force. The voice traffic intercept detach­ panels by the infantry is a satisfactory but very slow ment at the several TACs and the code intercept and complicated method. It can only be done for spe­ detachment maintained continuous contact with each cially planned operations and has no place in day-to­ other and with the static British intercept organiza­ day fighting in the advance to objectives by a division. tions in the United Kingdom so that all information With the proper training of pilots and installation of gained by the various units was readily available to communication equipment, it should be possible to each. Static organizations in the United Kingdom sup­ control medium bombers in the same manner as ported the activities of the field units by regular fighter-bombers. As for heavy bombers on this type periodic broadcasts of intelligence. of mission it would be better to use the pathfinder The operational employment of the units in the technique now used in bombing cities than the pre­ field and their service to the Commands proved su­ sent method used for close cooperation." perior in all cases. Ill CORPS. "There have been too many acci­ On D plus 3, the first echelon of the mobile voice dents attributed to faulty identification methods. Panel intercept detachment of the IX Tactical Air Com­ markers are generally conceived to the most effective mand landed in Normandy, and shortly after began to for air-ground identification." intercept German radio traffic of operational value. The service rendered by this detachment was supple­ 6TH ARMD DIV. "The use of tactical aids such mented by extensive reports made to them by the as smoke and panels has been very satisfactory, British "Y" Service and Air Ministry in the United however, further developments along these lines are Kingdom. deemed necessary. For instance: infantry troops on The results of the proper application of "Y" the ground could be provided with cerise and yellow Service Intelligence are proved by statistical records. panels to be placed on the backs of foot troops to From information based on "Y", the aircraft of be uncovered when necessary." the IX TAC shot down 180 aircraft. This figure does 2ND ARMD DIV. "The use of smoke has been not include aircraft shot down as a result of recom­ mended sweeps based on findings from "Y" informa­ somewhat overemphasized in that some pilots are tion, but only those enemy aircraft shot down as a prone to substitute it for map reading and target result of the immediate warnings or locations given identification. It should be clearly understood by the controller by the "Y" officer in the control room. all pilots that smoke indicates the locality but is not Further results from immediate warnings were the necessarily on the target. The target must be spotted breaking up of many ground attacks before the enemy after the smoke is picked up. Ground controllers aircraft could reach their target. In addition, many should help by telling the pilots where the target is enemy attacks on our bombers were broken up before with relation to the smoke. Display of panels has the latter were within range. been the subject of considerable attention in this The traffic from the local detachment, together division. Uniform methods of display have been with that intercepted by the British and American adopted giving maximum visibility from the air and mobile intercept stations and British static stations minimum visibility from the ground. The code color in England, was analyzed in each, ^Command by the system now in use is absolutely correct." A-2 signal intelligence officer. This officer main­ 377 Part Il-C Tactics tained complete time, area, base and strength-of 3. COMBAT TACTICS AND TECHNIQUE. effort charts. Overlays of the enemy's routes, taken a. FIGHTER-BOMBERS: from "Y" and radar plots, were also made daily. Based on such information, the A-2 Section was often (1) Basic Formation: Just as aircraft design is a enabled to make recommendations as to fighter compromise between weight, power, drag, and lift, sweeps. formation flying is a compromise between mutual protection or cross cover, ease of flying, and ease of The following is an extract based on "Y" in­ control. The leader must take into consideration such formation, made 24 August 1944: circumstances as the likelihood of enemy attack, "It is recommended that sweeps be flown as clouds, and visibility and adapt to them a standard follows: from 1400-1540 hours; the route to be flown basic formation agreed upon in advance. In general — in at Evreux to Boissy De Bois, thence East Creil during the climb and when flying over what is con­ — to Rheims, thence North to Laon and to St. Quentin, sidered friendly territory, the formation is flown rela­ thence southwest Beauvais and Rouen and return." tively close, to rest the pilots and save fuel. Enemy aircraft were encountered around 1400 In the European Theater, the basic unit of the hours in the vicinity of St. Quentin. Score: 41 enemy fighter-bomber formation was the four-plane flight, aircraft destroyed. made up of two two-plane elements. The wing men Interception of enemy radio messaged proved flew off to the side of their element leaders from 50 expecially valuable during the temporary resurgence to 75 yards, while the interval between flight leaders of the Luftwaffe at the time of the Ardennes counter­ and element leaders was from 75 to 100 yards. All offensive. "Y" information frequently made it possible planes flew level with their flight leader and, in most to warn our squadrons of impending attack or enable of the groups, between the line abreast and the line them to surprise enemy formations in the vicinity. 30° back from him. In some of the groups all four The suggestion has been advanced that radio planes of the flight flew abreast. interception detachments be made an integral part In a sixteen-plane squadron, the four flights of the Tactical Air Command which they serve. In were divided into two sections, red and blue. The the Ninth Air Force, these detachments were attached two flights in the red section flew line abreast from to the Commands rather than assigned. It is believed 200 to 300 yards apart. The blue section flew about that this system is preferable to assignment. The pri­ 300 yards behind the red section and from 500 to mary reason for maintaining a centralized control lies 1000 feet higher. In both sections the up-sun flight in the intricacies of the interchange of information flew slightly lower. between the several field units. It is mandatory that In a twelve-plane squadron, the flights flew in a all function in similar fashion, and that each should loose, shallow V, with 200 to 300 yards between be aware of its responsibility to contribute to as well them. The flanking flights were not more than 30° as benefit from, the work done by the others. The to the rear of the line abreast of the squadron leader. integration of the work of these separate units can Again the up-sun flight flew a little lower and the only be accomplished by uniformity in operation. In down-sun flight a little higher than the lead flight. the highly fluid development of the Ninth Air Force, it was fortuitous that centralization control of all de­ In a group formation of three squadrons, the tachments rested with Air Force Headquarters, as squadrons flew in a loose, shallow V, similar to the the provision of additional units and the equitable formation of flights in a twelve-plane squadron. The distribution of personnel and equipment was greatly interval between squadrons varied from 600 to 1000 facilitated. yards. The down-sun squadron flew 2000 feet above the group leader and the up-sun squadron 1000 to It should further be realized that the personnel 2000 feet below. of the operating radio squadron were not concerned with the collection of intelligence received from this On called turns of 60° or more flanking flights source nor with the appraisal of it in the light of and flanking squadrons crossed to opposite sides. intelligence from other sources. It was found neces­ (2) Assembly and Return Through Overcasts: With sary at all echelons (Air Force Headquarters and a ceiling of 1000 feet or more, the group leader formed Tactical Air Commands) to provide two officers and his group beneath the overcast before starting enlisted personnel in the Intelligence Sections, whose through. The squadrons were formed from flights sole duty was to receive, interpret, and evaluate the in trail in prearranged assembly areas, one to the almost continuous flow of information from "Y" left and one to the right of the lead squadron. On a sources. In addition to passing immediate operational signal from its leader the group headed out on course, "Y" intelligence, they maintained a continuous com­ staying beneath the overcast long enough to allow mentary on the daily scale of enemy effort, the loca­ the elements of the formation to get settled. Then, tion of enemy operational units, the tactical employ­ starting with the lead flight of each squadron, the ment of the enemy forces, enemy reaction to Allied flights went up individually, with a prearranged power offensive action, all of the foregoing being integrated setting and air speed. Simultaneously the flanking with intelligence available through other mediums. squadrons altered their course 10° away from the 378 ! I Part Il-C Tactics

lead squadron, turning back on course after ap­ ferably out of the sun. The planes peeled off on the proximately one minute. The flights within each target in string, throttling back if necessary to pre­ squadron followed their lead flights in line astern, vent excessive speed. The angle of dive varied from allowing 30 seconds between flights. Within each 45° to 60°. flight planes flew close enough to the leader to permit The actual technique employed in aiming and visual reference. Whenever a pilot lost sight of the dropping the bombs was best developed by the in­ flight leader, he immediately went on instruments dividual pilot. The needle and ball had to be centered and turned 10° away from his leader, holding the when bombs were released, and the release altitude same setting and air speed. Assembly of the group between 2000 and 3000 feet to permit recovery at a was made on top of the overcast and on course to minimum of 1000 feet. Normally the plane pulled conserve time and fuel. out in a climbing turn in order to regain altitude as When the cloud base did not permit assembly quickly as possible, although under certain conditions below, flights or even single planes climbed through it was more advisable to continue on the deck flat individually on a predesignated course immediately out, e.g., when flak was concentrated in the immediate after take-off. The unit was then assembled by circling target area and the surrounding countryside was on top. flat and undefended. In either case, violent slipping Letting down through the overcast was done and skidding were highly recommended. Since the by individual flights. With a very low ceiling, the let­ plane was most vulnerable during the breakaway, down could be controlled from the tower. this should not have been made over an intense flak area. (3) Flak Evasion: Flights to and from target areas were ordinarily made at altitudes beyond the range Sometimes, in order to neutralize the flak posi­ of light flak, i.e., at 8000 feet or higher, and whenever tions, anti-aircraft gun positions were strafed during possible, were plotted so as to avoid heavy flak areas. the bombing run. Whenever intensive flak positions When heavy flak was expected or encountered, the were spotted, a flight or more could be ordered to flights took evasive action but not so violently as to strafe them in an overhead pass while the others break up the group or squadron formation. If the flak bombed. was intense and accurate the unit leader called "Bus­ Cover was always provided for the unit bomb­ ter", i.e., military power, in order to clear the area as ing, which was highly vulnerable to enemy air attack soon as possible. during the run. If a group target was being attacked, (4) Radio Discipline: Radio discipline was strict­ two squadrons provided cover while one bombed. If it were a squadron target, two flights provided cover ly enforced for two reasons. The enemy relied to a while one or two flights bombed. great extent on our radio conversation for knowledge of our intended action, and on occasion the Germans (7) Glide-Bombing: Glide-bombing was some­ vectored fighters or even scheduled missions on the times used in preference to dive-bombing when one strength of an indiscreet radio message. It was also or more of the following conditions prevailed: (a) imperative that the radio channel, whenever badly whenever range errors were relatively unimportant needed, be clear of noise. For this reason pilots made but deflection errors were of utmost importance, a practice of condensing messages and allowing a (b) when cloud cover of below 7000 feet precluded short time interval between them. Aircraft flying non- a dive-bombing attack, and (c) when expected ground operational missions maintained absolute radio si­ defenses were such that the attack could be made lence on an operational frequency. without excessive danger. This was especially im­ portant since the glide-bombing approach, unlike (5) Procedure on Abortives: Whenever a pilot that of dive-bombing, was made at an altitude within felt that his airplane was incapable of completing his the range of light arms ground fire. assigned mission, he briefly indicated his trouble to the squadron leader, who usually directed him to The technique of glide-bombing was very simi­ return to the base and provided escort if it was war­ lar to that used in dive-bombing. With the exception ranted (e. g., over enemy territory, in bad weather). that the altitude was from 3000 to 5000 feet, the ap­ Spares filled in immediately if available. proach to the target was the same. The angle of the dive was approximately 30°; with a shallower angle (6) Dive-Bombing: In general the unit approached the bomb would tend to skip rather than penetrate the target with planes in loose echelon and flights a horizontal surface. The bombs were released at roughly in trail, at approximately 90° to the direction the lowest possible altitude that would allow recovery of attack and from 7000 to 10000 feet up. During from the glide, generally at 800 feet. Because of the the approach it was desirable to change altitude con­ high vulnerability to flak at that low altitude, speed tinually in order to evade flak. was essential, and the throttle was not retarded. The The direction of attack depended on, among attack should have been along the long dimension other things, the nature of the target, the wind, and of the target, for, in this type of bombing, deflection the sun. Thus, for example, other factors being equal, errors were negligible, whereas range errors were a bridge should be attacked along its long axis. The considerable. The breakaway- was the nrtme as that bombing should be done up or down wind and pre- for dive-bombing. 379 Part Il-C Tactics

I 1

380 Part Il-C Tactics

Photo 48 — Strafing Attack on M/T in Germany 381