The de Havilland Mosquito was a British light bomber that served in many roles during and after the Second World War. Mosquito-equipped squadrons performed medium bomber, reconnaissance, tactical strike, anti-submarine warfare and shipping attack and night fighter duties, both defensive and offensive.Bowman 2005, p. 7. Mosquitos were widely used by the RAF Pathfinder Force, which marked targets for night-time strategic bombing. Despite an initially high loss rate due to low-level daylight attack operations, the Mosquito ended the war with the lowest losses of any of the aircraft types in RAF Bomber Command service.
Performance On its introduction to service, the aircraft was about as fast as the German fighters that opposed it, particularly the Bf 109F and the Fw 190A. Although the differential in speed was low, the agility of the Mosquito was often an advantage. Aerial interception usually occurred when enemy fighters had already been "scrambled" by reports of visual sightings as the flights crossed the Continental coastlines. Occasionally, the daylight low-level raiding Mosquito squadrons simply had bad luck, as was the case with the Oslo Mosquito raid, 25 September 1942, when a crack Luftwaffe squadron of Focke-Wulf Fw 190 fighters of 3/JG 5 had just arrived in Norway.
In the first few years of Mosquito service, most of the dedicated Luftwaffe night fighter groups were equipped with aircraft such as the Bf 110 or Junkers Ju 88, both of lower performance. There were enemy attempts to address this but problems included engine troubles and the intensifying Allied bombing campaign, especially as the USAAF daylight bombing started to complement the RAF Bomber Command campaign. In terms of better propeller-driven night fighters, the Heinkel He 219 and Junkers Ju 388 simply did not enter large-scale production.
With the introduction of the nitrous oxide-boosted Messerschmitt Bf 109 G series and, in the spring of 1944,Radinger & Schick 1996, p. 49 the jet-powered Me 262, the Luftwaffe had relatively low numbers of fighters with a speed and altitude capability effectively to intercept the pressurised variants of Mosquito. But the German High Command would not give clear orders for their quantity production, which in any case would have been difficult because construction work had to be taken further east and carried out in concealed factories and tunnels. Aircraft fuel supplies were by then also becoming highly critical for the Nazis. Hitler in particular was at this stage fixated on "vengeance" weapons rather than fighters, denying leaders such as Adolf Galland any effective resources.
Nevertheless, on 25 July 1944, a PRXVI Mosquito from No. 544 Squadron RAF was intercepted in the Munich area and attacked by Leutnant Alfred Schreiber, flying an Me 262 A-1a. The German fighter made six passes at the Mosquito MM 273, crewed by F/L A.E. Wall and F/O A.S. Lobban, but they managed to escape into cloud after violent evasive manoeuvers, making an emergency landing at Fermo airfield in Italy. The PR Mk 32 photo reconnaissance Mosquito design attempted to counter the threat of the German jets with extended, long-span wings, special high-altitude superchargers and the elimination of as much weight as possible, raising its cruising altitude to 42,000 ft (13,000 m), above the service ceiling of the Me 262.
RAF Bomber Command
Low-level Daylight Attack Phase From around the start of June 1942 to the end of May 1943, the two RAF Squadrons who were the first to be equipped with Mosquito Mk. B.IV bombers operated as a low-level daylight bomber force in precision raids. On 15 November 1941, 105 Squadron, RAF, took delivery at RAF Swanton Morley, Norfolk, of the first operational Mosquito Mk. B.IV, serial no. W4064.Scott 1999, p. 6. No. 150 Squadron also had the first Mosquito to enter service (W4066). For nearly a year, in 1942 and 1943, 105 Sdn., based next at RAF Horsham St. Faith, then from 29 September, RAF Marham, undertook daylight low-level and shallow dive attacks.Wooldridge 1993, Frontispiece.. On 29 August 1942, Mk IVs of 105 Squadron RAF undertook a bombing mission against Pont-à-Vendin. They were attacked head-on by Focke-Wulf Fw 190s that then turned to fire again from the stern. The Mosquitos used their speed to outpace the 190s. On 19 September, Mosquitos attacked Berlin for the first time in daylight. Once again, when a Mosquito piloted by D.A.G ″George″ Parry was attacked by Messerschmitt Bf 109s, he was able to outrun them. One Mosquito failed to return.Bowman 2005, p. 34. Another of the early low-level missions was the Oslo Mosquito Raid (1942), carried out by four aircraft of No. 105 Squadron RAF, after which the Mosquito was publicly revealed for the first time.Bowman 1998, p. 13.
The second squadron to be re-equipped with the Mosquito bombers was 139 Squadron, based alongside No. 105 Sqn. at RAF Horsham St. Faith and then Marham. Their aircraft started to be delivered in September 1942; meanwhile they shared some machines of No. 105 Squadron. On 6 December 1942 Mosquitos from 105 and 139 Squadrons participated in Operation Oyster, the 2 Group daylight raid against the Philips works at Eindhoven. During the months from mid-1942 to the end of May 1943, they participated in the low-level daylight attack phase described by Wooldridge, including the first day of Berlin raids.
First Berlin raids On 30 January 1943, two daylight missions were carried out to bomb Berlin using low-level daylight tactics. These attacks were timed to disrupt speeches by Reichsmarschall Hermann Göring, head of the air force, and Joseph Goebbels, the Third Reich's Propaganda Minister. The first, in the morning, comprised a flight of three Mosquito B Mk. IVs from 105 Squadron, which attacked the main Berlin broadcasting station,History of the de Havilland Mosquito RAAF Museum at 11:00, when Göring was due to address a parade commemorating the 10th anniversary of the Nazis' being voted into power. The mission gave the lie to Göring's claim that such a mission was impossible, and kept Göring off the air for more than an hour. A second flight of Mosquitos from 139 Squadron followed in the afternoon of the same day to attempt to interrupt a speech by Goebbels at the Sports Palace. Once again, they bombed at the exact planned time. However, Berlin's anti-aircraft defences were on the alert and a Mosquito flown by Squadron Leader D.F.W. Darling DFC was shot down, killing both Darling and his navigator.Bowman 1997, p. 19Bowman 2005, p. 37. Göring was enraged; six weeks later he harangued aircraft manufacturers that he could "go berserk" when faced with the Mosquito, which made him "green and yellow with envy".Boog et al. 2006, p. 407.
Pathfinder operations Within Bomber Command, Pathfinder Operations were set up by (at the time) Acting Group Captain Donald Bennett, who was appointed Commander of Pathfinders (PFF) on 5 July 1942 After completing its initial Oboe trials work, No. 109 Squadron RAF moved with its Mosquito B.IV's to RAF Wyton in August 1942. There it joined the re-formed No 8 (Pathfinder Force) Group, where the newly appointed Donald Bennett had just set up his HQ."Bennett" pp=202-203, 210 A calibration sortie over enemy territory took place on 20/21 December, using six 109 Sqn. Mosquitos to locate and bomb a power station at Lutterade in Holland. Then on 31 December/1 January 1943, 109 Squadron pioneered PFF Oboe target marking for eight Lancaster bombers that attacked Düsseldorf."Bennett" pp=217-218
Mosquito bombers were soon an important aircraft within PFF operations. They became the main element of the Light Night Striking Force (LNSF) and from early in 1943, they were used for target marking, particularly in the initial phases of the raid, when their pyrotechnics would be followed up by additions from the heavy Pathfinder bombers. The LNSF carried out high speed night raids with precision aiming and navigation. Their mission was twofold: they targeted small but vital installations; and acted as a diversion from the raids of the heavy bombers, simulating large formations through the use of Window. On nights when no heavy bomber raid was planned, the LNSF would continue to deny the German air defences a rest by means of 'nuisance raids' that were of increasing ferocity as the Group acquired more Mosquito bombers.
On 1 June 1943, the two pioneering Squadrons, 105 and 139, joined No. 109 Squadron within the LNSF whose "nuisance raids" were already gaining approval from Harris and Churchill."Bennett" p. 236 Initially they were engaged in moderately high level (about 10 000 ft.) night bombing, diversionary raids and dropping Window. They made 67 trips that summer, mainly to Berlin. Soon after, some of the 105 Squadron aircraft were equipped with Oboe. In June 1943 109 Squadron received Mosquito B.IX's, also fitted for Oboe, and with their higher altitude capability they were able to extend its range. Other Mosquito Squadrons were added to No.8 PF Group with better Marks of the bomber, starting with B.IX's going to 139 Squadron.Birtles Chapter 8
From around December 1943, the Siren Tour series of spoof raids were deployed by the LNSF, mostly in northern Germany.
As Mosquito bomber production increased towards the end of 1943, No. 627 Squadron RAF was one of the first new bomber squadron to be added to the PFF. Based at RAF Oakington, it was staffed from part of 139 Squadron and equipped at first with B.IV's. It was involved in PFF attacks on Berlin in early 1944. No. 627 also attempted the second attack on Victoria Terresa (Oslo Mosquito Raid (1942))
Bennett was permitted to add considerably to the number of PFF Mosquito Squadrons - by May 1945 there were twelve of these, including the detached No. 627 Sqn. which was in No. 5 Group."Bennett" pp 348 - 349 The expanding PFF Mosquito squadrons visited all of the well-known targets in Germany including Berlin, Hamburg, Cologne, Essen, Mannheim, Hanover, and Duisburg. They took part in many bombing operations as pathfinders, marking targets with flares for the massed formations of heavy bombers. Once the B.XVI variants with enlarged bomb bays were brought into service in February 1944, they dropped 4,000-lb blast bombs ("cookies") which were used on many raids, making the force a formidable weapon in its own right.Bennett, pp. 274-275 During 20/21 February to 27/28 March 1945 inclusive, No. 139 squadron made a series of 36 consecutive night attacks on Berlin with these large bombs.
During the allied advance across France, the Pathfinder group, due to the persistence of Vice Marshall Bennett,A.S. Jackson expanded its brief to perform short notice raids, such as the blind bombing, using Oboe, of the road from Falaise on 19 August 1944, as well as of St. Vith crossroads, during the Battle of the Bulge. The group also developed techniques for destroying railway tunnels by "skip bombing" delayed fuse bombs into tunnel mouths, and destroyed numerous other targets immediately behind the German lines as its brief was widened, along with that of the Mosquitos of No. 100 Group Bomber Command, to attack the enemy almost wherever they saw fit. The task of destroying V-1 launching sites was given to the group, as well as to others. It is the efficiency of these raids by Mosquitos that provides the generally quoted improvement of about 5 times over other bombers. It is estimated by the RAF that it took only 40 tons of bombs on average for them to destroy a site, versus 165 tons for a B-17, 182 tons for a B-26, and 219 for a B-29.