The Luftwaffe over the Bristol area 1940-44, page 1
Even before the outbreak of war the Luftwaffe had started the process of intelligence gathering, with clandestine photographic sorties being undertaken over the Bristol area by a special reconnaisance unit known as Gruppe Rowehl, after its commanding officer and father of German aerial photography, Oberstleutnant Theodor Rowehl. These flights carried out by Heinkel He 111's in civilian markings, on what were said to be route proving flights, operated mainly over local airfields and aircraft factories and the Parnall Aircraft plant at Yate is known to have been photographed in this way as late as August 29th 1939. Nevertheless, during the period known in Britain as the Phoney War RAF and Luftwaffe bombers had abstained from making deliberate attacks on each others towns and cities but this lull, which had existed in the West since war had been declared on September 3rd 1939, ended on May 10th 1940 when the German Army marched into the Low Countries. The following night British bombers commenced operations against German industrial installations, culminating on the night of May 15th with a raid by nearly 100 aircraft on the Ruhr area. This enraged Hitler who on May 24th stated "the Luftwaffe is authorised to attack the English homeland in the fullest manner, as soon as sufficient forces are available. This attack will be opened by an annihilating reprisal for English attacks on the Ruhr".
As the subjugation of France neared its completion the spheres of operation were defined for the two major Air Fleets facing Britain. Luftflotte 2, based in the Low Countries, was to attack targets on the eastern side of the country, while Luftflotte 3, whose aircraft were located west of the River Seine, was to concentrate its efforts on the west. The bomber units of Luftflotte 3 then moved their aircraft onto captured French airfields, which at last brought the Bristol area within range of their fully loaded bombers.
At first German air operations over Britain were carried out on a small scale, and these began with light probing raids by night, normally in Staffel strength, but sometimes carried out by as few as two aircraft on one target. These Störangriffe or harrasing attacks were, in the months that followed, directed against specific targets such as aircraft factories, dock installations, oil storage tanks, and specialised manufacturing plants.
The first such mission carried out against the West Country took place on the night of June 19/20th 1940 when the Bristol Aeroplane Company at Filton, as well as the docks at Avonmouth and Southampton, were targeted by about 7 He 111's of III/KG 27 flying from Merville airfield, near the Franco-Belgian border. Although the raiders claimed to have succesfully attacked the Filton plant the facts were somewhat different, and Portishead was as near as the German bombers came, 10 H.E.'s falling along the shore at about 02.15 hrs.
The following day German Radio proudly proclaimed, "Since May 10th enemy and chiefly British aeroplanes have uninterruptingly attacked open German towns. Last night again eight civilians fell victim to these attacks. The Luftwaffe has now begun reprisals against England. The revenge of the German Air Force for England's sly night piracy has begun. German forbearance is exhausted. The time for settlement has come".
Although the damage caused by these nocturnal raids was only slight, their nuisance value was considerable, with a few aircraft often causing sleepless nights over large areas of the country, as well as regularly disrupting production at factories engaged in essential war work. They were, in addition, a valuable way for the Kampfgruppen to learn the art of night navigation but, as a result of their premature use, the radio beams associated with the highly secret Knickebein bombing and navigation aid were quickly detected by the British enabling effective counter-measures to be put in hand.
Knickebein, named after a German folk tale magic crow who could see in the dark, was available to the entire bomber force, its signals being picked up on the 'blind' landing receivers fitted as standard to all German bombers. When used for navigational purposes only one beam was employed, but for radio assisted bombing the system employed two transmitter stations which formed a beam intersection over the prescribed objective, allowing the attack to take place without reference to the ground below.
The next operation against the area was undertaken on the night of June 24th when five Heinkel He 111's of I/KG 27 were briefed to attack the Bristol Aeroplane Co. at Filton, which they again claimed to have successfully raided. The facts, however, were somewhat different, and at 00.17 hrs the first 1 kg I.B.'s fell in the St.Philip's area of Bristol, followed shortly after by the first H.E. which impacted at the corner of Lower Maudlin Street and Harford Street killing two people. Harassing attacks against local targets were now being being undertaken almost every night, and during the course of a nuisance attack on the harbour installations at Bristol and Cardiff on June 30/31st, a transmission from the Kleve Knickebein transmitter was monitored for the first time over the West. On this occasion the beam was laid over Filton and St.Athan, near Cardiff, on a bearing of 84 degrees True.
In addition to the bombing missions, the Luftwaffe now embarked on a comprehensive photographic reconnaissance of Britain, the first sortie over Bristol being undertaken by an He 111 of the Aufkl�rungsgruppe Oberbefehlshaber der Luftwaffe, the successor to Gruppe Rowehl, on June 29th. The Aufkl.Gr.Ob.d.L. were joined in this work early the following month by part of the reconnaissance element of Luftflotte 3, the assorted Junkers Ju 88's, Dornier Do 17's and Messerschmitt Bf 110's of 3(F)/31, 4(F)/14, 3 & 4(F)/121 and 1,2 & 3(F)/123 subsequently flying regular photo-reconnaissance sorties over the area throughout the summer and autumn of 1940, sometimes dropping small bombs on targets of opportunity. Thereafter, however, as the British defences strengthened, they tended to restrict themselves to undertaking only immediate pre and post-raid coverage missions.
Meanwhile, on July 2nd the Luftwaffe had received instructions to gain and maintain air superiority over the English Channel, and this was quickly achieved. The victory, however, was tactical rather than strategic, because Britain's seaborne communications with the world were uninterrupted, the ships being loaded and discharged at ports on the western coast, difficult and dangerous for the Luftwaffe to reach in daylight. The harbour facilities such as those at Bristol, Avonmouth, Newport, Cardiff, Swansea, Liverpool, and Glasgow now assumed great importance to the British economy, and night harassing attacks against them, and the local aircraft industry, continued throughout the summer, the Bristol Docks complex and the Bristol Aeroplane Company at Filton each being targeted about 20 times between June 19th and the end of August.
In order to maintain the pressure on the defences it had also been ordered that during daylight hours precision pinpoint attacks were to be undertaken against specific important targets, usually associated with the local docks or aircraft industry. These surprise attacks were to be carried out by aircraft, either singly or in small groups, only with the aid of suitable cloud cover. The first such mission undertaken against a target in the Bristol area was that attempted on the Portishead Docks by three Ju 88's of II/KG 51 on the afternoon of July 3rd.
The following day a raid was carried out on the Bristol Aeroplane Company by a lone He 111 of III/KG 54, and although slight damage was caused to the roof of the Rodney Works the bomber was shot down by Spitfires of 92 Squadron on its return flight, crashing near Gillingham in Dorset, the first German aircraft to be lost on operations against the Bristol area.
From the fall of France until mid-July, Hitler had waited for word from London that the British were ready ready to negotiate a peace. He waited in vain and on July 16th issued 'Directive No. 16 on the Preparation of a Landing Operation against England'. The code name for the assault was to be Unternehmen Seel�we or Operation Sealion, and preparations for it were to be completed in by early August.
The blockade of Britain was now tightened, and following the closure of much of the East Coast to British shipping, aerial minelaying operations were extended to cover the important shipping lanes and harbour entrances on the western side of the country. This included the Bristol Channel and Severn Estuary, which was first mined by the Heinkel 111's of I/KG 4, based at Soesterberg, in Holland, on the night of July 17th. In order to maintain the pressure on the defences, and to interrupt vital war production, these missions were usually flown on nights when no harrasing attacks were taking place, thereby extending the amount of time an area remained under Red Alert, and on occasions, as with the reconnaissance aircraft, small bombs were carried, these often being aimed at searchlights or anti-aircraft gun sites.
The beginning of August saw the use of an unusual tactic by the Luftwaffe, when German bombers dropped aerial leaflets on various parts of Britain. These were reprints of Hitler's speech before the Reichstag on July 19th, his "Last Appeal to Reason". The first such sorties were carried out on the night of August 1st when Bristol and Southampton were the targets for the four Heinkel 111's of II/KG 55 flying from Chartres. Due, however, to a combination of bad navigation and poor visibility over the target area the majority of the leaflets intended for Bristol fell in South Wales and rural Somerset. That night also saw the Parnall Aircraft plant at Yate targeted for the first time, but again neither of the two He 111's of II/KG 55 succeeded in locating any of their objectives at Yate, Filton or Avonmouth.
As a prelude to the German invasion, the vital elimination of the RAF and its associated aircraft industry was scheduled to begin early in August, and the day for its launching was given the code name of Adler Tag , or Eagle Day. The plan required that the the fighter defences located to the south of a line between London and Gloucester be beaten down, a process that it was hoped would not require more than four days, while the total destruction of RAF Fighter Command should be achieved within four weeks, after which the invasion itself could begin.
Meanwhile, as part of the same plan, a day and night bombing offensive was to be directed against the British aircraft industry and to assist in this the He 111's engaged in mielaying were temporarily switched to conventional bombing. Adler Tag was provisionally fixed for August 10th, but due to poor weather conditions was postponed until the afternoon of August 13th, when the full might of the Luftwaffe was at last unleashed against Britain. In mid-August 484 aircraft were available to the bomber formations of Luftflotte 3, comprising the Ju 88's of KG 51, KG 54, LG 1 and KGr 806 in addition to the He 111's of KG 27, KG 55 and KGr 100. This force was further bolstered towards the end of the month by the arrival of the 33 Dornier Do 17's of KGr 606.
The following day German bombers ranged far and wide over the West of England and Wales, engaged in armed reconnaissance against RAF airfields and aircraft factories. During the afternoon, however, three Heinkel 111's of III/KG 27 were shot down over the Severn Estuary by Spitfires of 92 Squadron, with two coming to earth in Somerset. These, and other losses suffered that day proved to the Germans the inadvisability of sending unescorted bombers in daylight soties over those parts of England which were out of range of the single engined Messerschmitt Bf 109 fighters. The mammoth battles of mid-August, thereafter took place mainly over South East England.
Over the Bristol area, owing to bad weather, a period relative calm set in on the 19th, and this lasted until the evening of August 22nd. It was then that conditions improved enough to allow KGr 100, the only unit in the Luftwaffe to be equipped with the sophisticated X-Verfahren electronic navigation and bombing aid, to carry out their first precision attack under Luftflotte 3, the target being the Bristol Aeroplane Company at Filton.
X-Verfahren was a complex system employing a main and three cross beams which gave the pilot aural indications 50 km, 20 km and 5 km out from the target. It's chief disadvantage, however, was that it was only able to operate in conjunction with specially-equipped aircraft manned by crews trained in its use.
The operation against Filton involved 23 He 111's which were dispatched from their newly established base at Vannes in Brittany flying along an approach beam radiated from the X-Beam transmitter at Cherbourg. Over Bristol it was a clear moolight night up to 02.00 hrs after which some cloud developed at 3000 metres. During the attack, which took place between 23.19 and 02.50 hrs, the 16.65 tonnes of H.E.'s and 576 I.B's caused considerable damage to the works, in particular at No.4 Factory and No.11 Test Bed, and resulted in four people being injured. All the German aircraft, however, returned safely to base.
As part of the Luftwaffe's modified strategy, which now involved the concentration of forces over South East England, by August 24th the majority of Luftflotte 3's fighters had been redeployed to operate over that area. The problem now existed of what to do with the surplus bomber force, which being stripped of all its effective fighter cover, was unable to carry out daylight attacks, and night operations were the obvious answer. Accordingly Luftflotte 3's bombers were ordered to attack the next most important targets in Britain, the vital West Coast ports of Liverpool and Bristol.
Operations started immediately and that night the He 111's of I, II and III/KG 27, together with the Ju 88's of I and III/LG 1, a total of 44 aircraft, were dispatched to attack the harbour installations at Bristol. 41 crews subsequently reported over the City claiming to have dropped 27.2 tonnes of H.E.'s, 13 tonnes of Oil Bombs and 5364 I.B.'s in a raid which lasted from 21.40 to 05.09 hrs. The attack, however, was not a success and although the weather over the Bristol area was fine, low cloud impeded visibility, with the result that the majority of the bombs fell fairly harmlessly in North Somerset.
Liverpool was now selected for the first really heavy raid of the war, and on the night of August 28th 160 aircraft were dispatched to attack the harbour installations, while a further 23 Do 17's of KGr 606 made for Bristol where they claimed to have dropped 9.5 tonnes of H.E.'s and 900 I.B.'s. Locally the weather steadily deteriorated throughout the night, with heavy cloud varying in intensity from 1000 to 3000 metres, and although the German crews claimed to have successfully attacked Bristol through the haze, few bombs fell anywhere near the City.
During the first week of September the bombers of Luftflotte 3 continued to attack Liverpool, with Bristol, including Avonmouth and Portishead, being targeted by 31 aircraft drawn from I,II, and III/KG 51 and I and III/KG 55 on the night of September 1st. Over the Bristol area the weather was fine, with good visibility up to about 23.00 hrs, after which severe ground mist arose, particularly in low lying ground. The attack itself took place between 20.15 and 03.30 hrs, with the Germans caliming to have dropped 22.9 tonnes of H.E.'s and 9 tonnes of Oil Bombs, but due to ground haze the efect was not seen. Not surprisingly the raid failed to cause any serious damage, with bombs being scattered from Avonmouth, across Stoke Bishop and the City Centre to Redfield. Bristol's casualties, however, amounted to 9 killed and 14 injured.
The raiders returned on the night of the 3rd when 21 He 111's from Stab, I, and III/KG 55 attempted a raid on the docks complex at Avonmouth, attacking between 21.45 and 01.22 hrs with 13.7 tonnes of H.E.'s and 7.75 tonnes of Oil Bombs. Although it was a clear starlit night with no moon, giving perfect visibility over Bristol, only minor damage was caused at Avonmouth, the raid having infact spread itself along the North Somerset coast, with four people being killed and five injured at Portishead.
The last of the series of attacks took place the following night when 47 aircraft of I/KG 27, II/LG 1, I, II, and III/KG 51, along with I and II/KG 55 reported over Bristol and one over Avonmouth between 21.20 and 04.47 hrs, claiming to have dropped 45.05 tonnes of H.E's and 9.25 tonnes of Oil Bombs. Locally the sky was perfectly clear until the early hours of the morning when a ground mist arose which was particularly heavy in certain localities. On this occasion the majority of damage occurred in the Clifton, Redland, St.Anne's and Knowle areas of the City, while at the Bristol Aeroplane Company's premises at Filton an Oil Bomb caused a fire in No.2 Shop, which resulted in a request for the Bristol Fire Brigade to attend. Total casualties amounted to 4 killed and 6 injured.
A feature of these attacks on Bristol in early September was the complete reliance upon Oil Bombs for fire raising, with a total of 105 of the 250 kg weapons being employed during the three nights. The raids on the West Coast harbours were the heaviest yet experienced in Britain, and although Luftwaffe losses were minimal, no aircraft at all being lost against Bristol, the result were not particularly good, the bombing lacking the concentration required to cause any real disruption.
Meanwhile bombs had fallen on Central London for the first time during the night of August 24th, when several aircraft attacking Thameshaven inadvertently dropped their load too far west. In Britain this was seen as an extension of the indiscriminate bombing already experienced in the provinces for, regardless of intent, this was the effect of most German night raids. The following night, on Churchill's instructions, Berlin was attacked by the RAF, and although the British attempt at retaliation was weak and ineffective, it infuriated Hitler, resulting in London superseding RAF Fighter Command and its supply organisation as the primary target of the Luftwaffe.
Reichsmarschall Hermann G�ring assumed direct command of the air offensive against Britain on September 7th, and that afternoon the Luftwaffe flew 372 bomber sorties against targets in East London starting large fires and causing considerable damage. This was the beginning of a series of raids that was to last for 65 days, and initially many of Luftflotte 3's aircraft, previously available to carry out attacks on the Bristol area, were ordered to re-direct their efforts to the Capital.
September also marked the start of a systematic series of daylight pinpoint raids carried out by a small force of twin-engined Messerschmitt Bf 110 fighter-bombers of Epr Gr 210, flying with long range Bf 110 fighter escort, on some of the most important British aircraft factories. The attack series opened with a raid on the Vickers plant at Weybridge on September 4th, shortly after which Epr Gr 210 and the long-range fighters of ZG 26, about 90 aircraft in all, were temporarily transferred to Luftflotte 3. The first operation under their new command was carried out against the Supermarine factory at Woolston, near Southampton, on September 10th, and it was not to be long before they were operating over the Bristol area.
Also on that day G�ring ordered that if the weather situation prevented large scale operations against London, then surprise daylight attacks by individual bomber aircraft were also to be made on targets associated with the British aircraft industry. These were to be undertaken by crews specially selected for their skill and experience, and were only to be flown in low cloud and often appauling conditions in an attempt to prevent interception by RAF fighters.
These missions became known to the Luftwaffe crews as Pirateneinsatze or Pirate Attacks, and the first such operation carried out against a target in the Bristol area was the attempt, by a lone He 111 of I/KG 55, on the Bristol Aeroplane Company at Filton on September 16th.
It now seemed unlikely that full air superiority would now be achieved by the Luftwaffe before the onset of worse weather, and so on September 17th Hitler ordered the indefinite postponement of the invasion. Two days later, as a result of this change in strategy instructions were issued to increase the attacks against the British aircraft industry, both by night and day, by reducing the size of the formations engaged in raids on London.
Accordingly the bomber force of Luftflotte 3 was once again assigned the most important targets on the western side of Britain, and as part of a new strategy September 25th saw the start of a planned series of large scale daylight attacks, in Geschwader strength with long range fighter cover, on the aircraft industry in the West Country.
The target that morning was the Bristol Aeroplane Company at Filton, and the weather was perfect for bombing, with banks of thick cloud broken by patches of clear blue sky. As a result the works was successfully attacked at about 11.45 hrs by 58 Heinkel He 111's of KG 55, escorted by 52 Bf 110's of ZG 26.
The raiders were not intercepted by RAF fighters until they had left the target area, but the local anti-aircraft gunners scored their first success, an He 111 of II/KG 55 which was brought down at Failand during its run in to the target. A total of 6 German aircraft failed to return, which resulted in 8 crewmen being killed and 10 made prisoner, including 5 injured. In addition a further 2 aircraft crashed on return to France, adding 2 more injured to the casualty list.
Serious damage had indeed been caused at the Rodney Works, while here and at the Flight Shed and East Engine Works, the workers shelters were hit by a stick of bombs, causing many casualties. The attack which only lasted some 45 seconds also destroyed eight newly built aircraft, including two precious Beaufighter prototypes, and production was temporarily halted. Over Filton and surrounding districts 81.5 tonnes of H.E.'s and 6 tonnes of Oil Bombs had been dropped, which tragically resulted in the death of 132 people, of which 91 were Company employees, while a further 315 were injured.
The crew reports, and photographs taken by KG 55 during the attack, together with a reconnaissance mission flown over Filton later that day by a lone Bf 110 of 4(F)/14 proved to the Germans that the raid had been a great success. Accordingly the Luftwaffe's own magazine, Der Adler, soon after proudly proclaimed "this factory will not produce many more aircraft", while Major Friedrich Kless, the attack leader and Gruppenkommandeur of II/KG 55, was awarded the Ritterkruz on October 14th.
September 27th saw the return of German aircraft in daylight over Bristol, when 10 Bf 110's of Epr Gr 210 escorted by 42 long-range fighters undertook an unsuccessful pin-point attack on the Parnall Aircraft works at Yate. The weather during the morning was fair, with patches of cloud, and for the citizens of Bristol this offered the unique opportunity to witness a classic 'dog-fight' over the City. During this action two escorting Bf 110's of I/ZG 26 were shot down by the Hurricanes of 504 Squadron, which had only arrived at Filton the pervious day. One of the Messerschmitts disintegrated over the Stapleton Institution at Fishponds, and was the only enemy aircraft to crash within the Bristol boundary during the Second World War, while the other came down at Haydon, near Radstock.
During the raid Epr Gr 210 had lost about a third of its aircraft and a number of senior officers, including the Gruppenkommandeur, Hptm. Martin Lutz, and the Staffelk�pitan of 2 Staffel, Oblt. Willhelm R�ssiger, both of whom were posthumously awarded the Ritterkreuz on October 1st. One officer who took part in the raid and did survive the devastating attack by RAF fighters, was Hptm. Wilhelm Makrocki the Gruppenkokommandeur of I/ZG 26, and he received his Ritterkreuz on October 6th.
A total of 10 German aircraft infact failed to return which resulted in the death of 14 crewmen, with 6 others being taken prisoner, 5 of them injured. The Luftwaffe obviously could not sustain the terrible losses of September 27th, and thus was brought to an abrupt end this type of fighter-bomber attack on West Country targets.
The large scale daylight bomber attacks, however, continued until October 7th when 25 Ju 88's escorted by 50 Bf 110 long range fighters, mounted a daylight attack on the Westland factory at Yeovil in which nine aircraft were shot down, seven of them Bf 110's, which were proving no match for the RAF's single engined Hurricanes and Spitfires. With such losses being suffered the time was now quickly approaching when any attempt at large scale daylight raiding would have to be abandoned, and on the 19th the poor weather gave G�ring the excuse he needed to terminated these attacks.
During October London continued to be the principle target for the long range bombers, being raided every night. However with the planned invasion of Britain now shelved the Luftwaffe High Command ordered more bombing effort to be put into night harassing attacks on the harbour installations at Bristol, Liverpool and Glasgow, with the industrial centres of Birmingham and Coventry as alternative targets, while still maintaining the pressure on the Capital. As a result I Fliegerkorps was transferred to Luftflotte 3 adding to its inventory the He 111's of KG 1 and KG 26 as well as the Ju 88's of KG 76 and KG 77, although, a number of these units were to remain non-operational for some time.
Luftflotte 3 was also to continue pin-point Pirate daylight attacks by single aircraft against important centres of the British aircraft industry when weather permitted. The plants at Filton and Yate were once again prime targets, and operations commenced on October 6th when a lone He 111 of II/KG 55 attempted an afternoon raid on Yate. The Parnall Plant, however, was not attacked as the essential cloud cover started to break up, forcing the crew to bomb Bournemouth as an alternative.
These missions were also interspaced with more conventional operations by single night bombers, with Filton being targeted twice, and Yate once in unsuccessful attacks carried out by II and III/KG 55 between the 10th and 15th of October.
The daytime Pirate attacks had also resumed on the 15th, when Oblt. Speck von Sternburg of III/KG 55 made an abortive attempt against Filton, to be followed by three more unsuccessful efforts later in the month by the same crew. On the 19th the mission was again aborted, on the 24th the bombs fell at Yatton, and on the 31st of October the Royal Ordnance Factory at Glascoed in South Wales was bombed, being mistaken for Filton! For this attack the crew received a mention in the High Command of the Armed Forces Communique issued on November 2nd, in which it was stated that they had destroyed a factory near Bristol.
The first minelaying campaign to block the approaches to Bristol, Avonmouth and the South Wales ports had ended with the opening of the Adler offensive on August 13th, but in late October, with the abandonment of the planned invasion and a switch to a policy of blockade, it was resumed by the He 111's of KGr 126 flying from Nantes in Brittany. This unit, re-designated I/KG 28 in December 1940, was to continued this work on and off until July 1941, and during the one year period that aircraft were mining in and around the Severn Estuary a total of 10 British vessels were sunk, while a further 9 were damaged.
Meanwhile the Luftwaffe's attempt at battering London to produce a British surrender was not proving at all successful, as the the bombing was too scattered over the great area of the metropolis to produce any large scale destruction, or collapse of civilian morale. As a result the attacks were now to be directed more against Britain's manufacturing base, followed by a concentrated assault on the ports as part of the policy of blockade, which was also to be integrated with an all out submarine war at sea.
Accordingly instructions were issued on November 8th ordering preparations to be made for attacks on Coventry, Birmingham, and Wolverhampton, to be lead by the X-Verfahren equipped He 111's of KGr 100. The first attack of the series, that against Coventry, took place on the night of November 14th, and was carried out by 449 long-range bombers. On November 21st the Luftwaffe High Command issued targeting instructions ordering Luftflotte 3 to attack the larger harbours in their operational area, starting with a raid on Southampton on the night of the 23rd.
During these operations the Germans considered that any lack of training in night navigation and bomb aiming would be more than compensated by the employment of their radio bombing beams. The premature use over England from June onwards had, however, compromised the secrecy of Knickebein, the only system available to the whole bomber force, and enabled the British to build jammers to counter it. These were to prove very successful and the Luftwaffe was soon deprived of a simple and efficient bombing aid. Sadly for the inhabitants of many British cities efforts were much less effective against X-Verfahren , and the Germans' latest development Y-Verfahren, which was about to make its operational debut over the area.
Y-Verfahren employed a highly complex single directional radio beam to provide track guidance to the target, while associated with this was a range measuring facility. Since it required only one ground transmitting station, and left minimum latitude for human error, Y-Verfahren was technically the most advanced of the German systems. The one serious disadvantage, however, was that unlike Knickebein and X-Verfahren, only one aircraft at a time could use the system because of the communications and other signals involved, and consequently an interval of five to ten minutes usually separated each attacking aircraft.
The two specialist units, KGr 100 equipped with X-Verfahren, and III/KG 26 operating Y-Verfahen , became collectively known as Beleuchtergruppen or Firelighters serving as pathfinders for the main bomber force. Their aircraft were employed to start fires during the early stages of an attack, which helped to guide the normal bomber units to the target area.
They were assisted by a third unit II/KG 55, which although not officially recognised as a Beleuchtergruppe, had considerable opertational experience and had displayed particular skill at finding targets at night. It was this unit, employing standard navigational techniques, that dropped parachute marker flares and very high calibre bombs at the commencement of major attacks on the West Country during the winter of 1940/41.
The H.E.'s carried externally on their aircraft were used not only to created fires, but also in an attempt to damage the water mains in the target area and so hamper the fire-fighters activities. In Bristol these 1800, 1700 and 1400 kg weapons were often mistaken for Land Mines, few of which were infact ever deployed against the City.
Because of the weak British defences concentration of effort in time and place was not considered necessary, and so the attacking aircraft operated singly over the target, at about four minute intervals. The various Gruppen involved were also ordered to attack at widely spaced times, to cause the maximum disruption, not only to the area actually under attack, but also to the country as a whole, by placing much of it under a Red Alert. As a result the attacks could last from dusk to dawn, although on occasion poor weather on the Continent necessitated operations to cease before midnight.
The orders for the night of November 24th were for the first major attack on Bruder, the German code name for Bristol, but as there had been a good deal of fog over Northern France earlier in the day, and a chance that it might return, it was decided operations should be completed by midnight. A total of 148 aircraft were ordered to the City, 135 of which claimed to have attacked between 18.30 and 23.00 hrs with 156.25 tonnes of H.E.'s, 4.75 tonnes of Oil Bombs and 12,500 I.B.'s.
The Concentration Point was centered on the harbour and industrial plant on both sides of the City Docks, with the intention of "eliminating Bristol as an importing port supplying much of the Midlands and South of England". The aircraft involved in this operation were drawn from I/KG 1, III/KG 26, LG 1, I and III/KG 27, KGr 100, KGr 606, I, II, and III/KG 51, Stab, I, II, and III/KG 55.
Late in the afternoon the RAF's Radio Monitoring Service reported that there were slight indications that X-Beams were aligned over Bristol, but KGr 100 subsequently claimed to have bombed only by Dead Reckoning and Knickebein. III/KG 26, however, attacked using Y-Verfahren , and the Cherbourg transmitter was monitored on 45.7 mc/s. In addition the Cherbourg and Dieppe Knickebein stations laid beams over the City during the evening.
The wind in the target area was moderate to gentle WSW, and parachute flares were successfully dropped by II/KG 55 at the commencement of the raid. Initially, however, because of broken high cloud bombing was undertaken mostly by radio and Dead Reckoning methods, but as the attack progressed the sky cleared and it became possible to bomb visually, guided by the fires which could be seen from some 250 kilometeres. In general the line of run-up to the target was from south to north, but later in the evening large cumulus clouds developed over the City, as a result of numerous fires, and some raiders were tracked flying round Bristol and approaching from the north.
At about 19.13 hrs the small gasholder at Marksbury Road, Bedminster had exploded and the high jet of flame this produced was noted by both KGr 100 and II/KG 55, although the latter assumed it to be a gasometer at target GB 52 52, the St.Philip's Gasworks. The general impression given by participating airmen was that results were similar to those achieved at Birmingham and Coventry. As a distributing centre and important railway junction Bristol, it was announced, had been wiped out. "Of all the ports on the West Coast, Bristol WAS the nearest and best situated for the Midlands, London and the South Coast". For the Germans it had been a very successful night and only 2 aircraft failed to return, as a result of which 4 crewmen were kiled and a further 4 made prisoner, including one who was injured.
The attack, however, resulted in the death of 200 Bristolians, and injuries to a further 689. It had concentrated on the central area, with further damage occurring in Clifton, Temple, Knowle, Barton Hill and Eastville, but greatest destruction took place in the heart of the City from Broad Quay to Old Market, while St.James' Barton and St.Philip's suffered severely. Exceedingly large calibre bombs were reported as having fallen at Eastville, Speedwell, Temple and Totterdown, while for the greater part of the night the City was blazing furiously and many well known buildings were totally destroyed and others gravely damaged.
Extensive fog on the Continent ruled out any more large scale raids for the next few days, but with good weather still prevailing at Vannes airfield, an X-Verfahren assisted attack was mounted by KGr 100 against the docks at Avonmouth on the night of November 25th. Nine aircraft participated, but with thick cloud over the target area only one serious incident resulted, this being a fire at the Shell Canning Factory at the Royal Edward Dock.
The next night, with fog still widespread on the Continent KGr 100 returned to Avonmouth with 7 aircraft, all operating with X-Verfahren, again against targets in the Royal Edward Dock. On this occasion there was thick cloud at 1200 metres with only occasional clear intervals, and no significant damage was caused, the majority of the bombs falling harmlessly on open ground in the Avonmouth and Shirehampton areas.
Bristol was the target for a second major raid on the night of December 2nd, but once again the operation was restricted to the first half of the night to allow the bombers to return to base before the onset of widespread fog on the Continent. Participating aircraft were drawn from 1 and III/KG 1, II/KG 77, II and III/LG 1, 1 and III/KG 27, KGr 100, KGr 606, I and II/KG 54, KGr 806, 1 and II/KG 55.
The attack, which the Germans claimed was to complete the work of destroying the industrial and port installations at Bristol, was carried out by 121 aircraft between 18.20 and 22.30 hrs, with 120.9 tonnes of H.E.'s, a tonne of Oil Bombs and 22,140 I.B.'s. Prior to the raid the RAF had correctly identified X- Beams laid over the City, and just before nightfall the Knickebein transmitter at Dieppe, previously deployed over London, suddenly swung round and to be re-aligned over Bristol.
In the target area at the start of the raid there was nearly 10/10ths cloud cover in two layers, the lower lying between 300 and 1000 metres, and the upper between 2500 and 3000 metres. Underneath, surface visibility was bad and down to 1000 metres, with the result that initial bombing was by Knickebein and Dead Reckoning methods. The general line of approach by the raiders was from the south, though a few aircraft were tracked in from the north-west.
Parachute flares and I.B.'s were dropped at the start of the raid by II/KG 55, but due to the exceptionally overcast conditions many initially fell over Clifton and the northern parts of the town. However, immediately after this opening attack Oblt. Otto-Bernard Harms, Staffelk�pitan of 4/KG 55, dived through both layers of cloud to an altitude of 300 metres to check on the positioning of the Gruppe's target marking fires. Despite the poor visibility he confirmed the accuracy which his Gruppe had achieved using Knickebein and Dead Reckoning, aided by the flares. This was undertaken with complete disregard to the Balloon Barrage and strong Anti-Aircraft defences.