De Havilland Mosquito operational history

The de Havilland Mosquito served in many roles during and after the Second World War. Mosquito-equipped squadrons were asked to perform medium bomber, reconnaissance, tactical strike, anti-submarine warfare and shipping attack and Night fighter duties, both defensive and offensive, until the end of the war. Mosquitos were widely used by the RAF Pathfinder Force, which marked targets for night-time strategic bombing. Despite an initially high loss rate, the Mosquito ended the war with the lowest losses of any aircraft in RAF Bomber Command service. Post war, the RAF found that when finally applied to bombing, in terms of useful damage done, the Mosquito had proven itself 4.95 times more cost-efficient than the Lancaster.

Performance
On its introduction to service, the aircraft was about as fast as the front line German fighters that opposed it, the Bf 109F and Fw 190A. Although the differential in speed was low, by the time those aircraft could reach interception altitude, the Mosquito would have completed its bombing run and would be racing for home. Advancements in German fighters eventually outpaced performance improvements in the Mosquito, but it was always an elusive target even in daylight.

At night, however, no Luftwaffe aircraft even came close. At the time the Mosquito was introduced, most of the dedicated night fighter groups were equipped with aircraft like the Bf 110 or Junkers Ju 88 of much lower performance. Although there were several attempts to address this by introducing a new night fighter of greatly improved performance, a variety of problems from engine troubles to the intensifying Allied bombing campaign meant that they never matured. The Heinkel He 219 and Junkers Ju 388, that were technically the Mosquito's equal, simply did not enter large-scale production. Their tiny numbers meant they were never a serious threat, and in the night bombing role, the Mosquito went largely unopposed for the entire war.

"…it was also the easiest and cheapest [Allied warplane] to repair. The lightweight fighter-bomber was so fast that the Americans issued standing orders for their swiftest plane, the P-38 Lightning, never to be flown alongside it."

With the introduction of the nitrous oxide-boosted Bf 109s and the jet-powered Me 262 late in the war, the Luftwaffe had interceptors with a clear speed advantage over the Mosquito. On 26 July 1944, a Mosquito from No. 540 Squadron RAF became the alleged first Allied victim of the Me 262 turbojet fighter. On that day, Leutnant Alfred Schreiber, flying a 262 A-1a, caught and severely damaged the Mosquito in a pursuit. The Mosquito, which managed to escape into cloud, later crashed at its destination airfield in Italy, and the airframe was written off. Other sources state the Mosquito sustained damage made during violent escape moves and escaped. The PR Mk 32 photo reconnaissance version of the Mosquito attempted to counter this threat 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), well above the service ceiling of the Me 262. While at least one PR Mk 32 aircraft was intercepted by FW 190s after losing an engine and descending to a lower altitude, it managed to escape, and none have appeared to have been lost in combat.

RAF bomber operations


The first bomber squadrons to receive the Mosquito B IV used it for several low-level daylight raids throughout the summer of 1942. On 29 August 1942, Mk IVS of 105 Squadron RAF undertook a bombing mission against Pont-à-Vendin. They were attacked by Focke-Wulf Fw 190s. The Fw 190s attacked head-on before turning to attack 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. One of the first missions was the Oslo raid on 25 September 1942, carried out by four aircraft of No. 105 Squadron RAF, after which the Mosquito was publicly revealed for the first time.

Berlin raids
Two notable daylight missions were carried out on 30 January 1943, when Mosquitoes carried out two attacks on Berlin timed to disrupt speeches being delivered by Reichsmarschall Hermann Göring and Joseph Goebbels, the Third Reich's Propaganda Minister. The first, in the morning, comprised three Mosquito B Mk. IVs from 105 Squadron, which carried out a low-level attack on the main Berlin broadcasting station, 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 Mosquitoes from 139 Squadron went to Berlin in the afternoon of the same day to attempt to interrupt a speech by Goebbels at the Sports Palace, and once again bombed at the exact 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, both Darling and his navigator being killed. Goering himself was not amused; 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."

Pathfinder operations
Mosquito bomber versions were used as part of Bomber Command; the Pathfinders and the Light Night Striking Force (LNSF) both of No. 8 Group. 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 chaff. On nights when no heavy bomber raid was planned, the LNSF would often strike to deny the German air defences a rest.

As part of 8 Group, Mosquitos took part in many bombing operations as pathfinders, marking targets with flares for the following massed formations of heavy bombers. Bomber Command Mosquitos flew over 28,000 operations, dropping 35,000 tons (31,751 tonnes) of bombs, and losing just 193 aircraft in the process (a loss rate of 0.7%, compared to a 2.2% loss rate for the four-engined heavies). It has been calculated that a Mosquito could be loaded with a 4000 lb "cookie" bomb, fly to Germany, drop the bomb, return, bomb up and refuel, fly back, drop a second bomb, and return, and still land before a Stirling (the slowest of Bomber Command's four-engined bombers) could strike Germany with a full bomb load.

The Mosquito inspired a conceptually similar German aircraft, the Focke Wulf Ta 154 Moskito, which, like its namesake, was constructed of wood.

A Mosquito B.IX also holds the record for the most combat missions flown by an Allied bomber in the Second World War. 'LR503', known as "F for Freddie" because of its squadron code letters, GB*F, first served with 109 and subsequently 105 Squadron of the RAF. It flew 213 sorties during the war, only to crash on 10 May 1945, two days after VE Day at Calgary airport during the 8th Victory Loan Bond Drive, killing both the pilot Flt. Lt. Maurice Briggs, DSO, DFC, DFM and navigator Fl. Off. John Baker, DFC and Bar.

618 Squadron - Highball and the Pacific
At the same time that Barnes Wallis was designing the famous Upkeep bouncing bomb to destroy German dams, he also designed a smaller version — Highball — for enemy shipping. It was decided that the Mosquito was an ideal aircraft to carry two of these weapons in modified bomb bays. To this end, 618 Squadron was formed in great secrecy on 1 April 1943 as part of Coastal Command. 618 Squadron's specialist role was to attack German shipping, with priority being accorded to the German battleship GERMAN BATTLESHIP Tirpitz.

The Mosquito selected for conversion to carry Highball was the Mk IV series II: the work entailed removing the bomb bay doors and equipping the aircraft with specialised carriers enabling them to carry two Highballs, each weighing 1,280 lb (580 kg), in tandem. The bombs were designed to skip across water and to provide weapon stability and accuracy. Before release, they were spun backwards at 700 to 900 rpm by a ram air turbine mounted in the bomb bay's midsection, fed by an extendable air scoop. The bombs were to be dropped from a maximum altitude of 60 ft (20 m) at a speed of 360 mph (600 km/h).

In the event, through lack of weapons, training and aircraft, 618 Squadron was kept frustratingly inactive and never attacked Tirpitz. Instead, the unit was selected for carrier-borne operations in the Pacific.

For this role, 25 Mosquito B Mk IVs were further modified:
 * Each aircraft was equipped with Merlin 25s, adapted to provide peak power at low altitudes, driving four-bladed Rotol propellers: these propellers had narrower blades than the standard three-bladed units, meaning that the engines would rev up faster and respond more quickly to throttle movement, factors vital in the limited length of carrier take-offs.
 * Longer intakes under the engine cowlings were fitted with tropical filters.
 * The undercarriage legs were made of heavier-gauge metals and the wheels were fitted with the twin brake units of FB Mk VIs.
 * The rear fuselages were structurally modified with a special internal longeron and reinforced bulkheads designed to take the additional loads imposed by carrier landings: an additional bulkhead (No. 5a) was fitted.
 * Externally a "vee frame" arrestor hook was fitted. The "snap gear" which released the hook was operated by a Bowden cable from a lever mounted on the cockpit port side.
 * An access hatch was moved from the starboard rear fuselage to underneath, and an extra longitudinal stiffening strake, identical to that already fitted to the starboard side of production Mosquitos, was fitted to the port fuselage.
 * The tailwheel fork pivots incorporated end plates to avoid being caught in the arrestor cables.
 * Armoured windscreens were fitted, along with hydraulic wipers.
 * Three P R Mk XVIs, which were to be used for reconnaissance duties were also fitted with the four-bladed propellers and fuselage modifications for carrier operations.

These Mosquitos were transported to Australia on board the carriers HMS Fencer (D64) and HMS Striker (D12), arriving on 23 December 1944. In order to keep up aircrew proficiency and safeguard the modified Mosquitos, 12 disassembled FB Mk VIs were also sent, arriving in Sydney in February 1945. These were reassembled at de Havilland Australia's Mascot factory. Once again, because of political-strategic infighting between the British Pacific Fleet and the U.S. military, the unit never saw action and was disbanded at RAAF Narromine in July 1946.

The converted Mosquitos were stripped of all military equipment and sold off. The sole surviving 618 Squadron Mosquito, an FB Mk VI HR621, is currently undergoing restoration at the Camden Aviation Museum, New South Wales.

RAF night fighter
The use of the Mosquito as a night fighter came about when the Air Ministry project for a night fighter (based on the Gloster F.9/37) was terminated so that Gloster could concentrate on jet aircraft development.

The first fighter Mosquito introduced into service was the NF Mk II in mid-1942, with four 20 mm (.79 in) Hispano cannons in the fuselage belly and four .303 in (7.7 mm) Browning machine-guns mounted in the nose. It carried the Aircraft Interception radar (AI) Mk IV / Mk V when operating as a defensive night fighter over the UK, although at the time this was omitted from Mk IIs operating as night "Intruders", roaming over Europe at night to cause maximum disruption to lines of communications and flying operations. These were fitted with the Serrate radar detector to allow them to track down German night fighters by emissions from their own Lichtenstein B/C, C-1, or SN-2 radar, as well as a device codenamed Perfectos that tracked emissions from German IFF systems.

On 30 May 1942, the NF Mk II scored its first kill, a Dornier Do 217 of Kampfgeschwader 2. By the end of the war, Mosquito night fighters had claimed approximately 600 enemy aircraft, along with 600 V-1 flying bombs. Among this total were 68 single-engined Focke-Wulf Fw 190s. This variant also operated over Malta, Italy, Sicily and North Africa from late 1942 on. The Mosquito NF XII became the first aircraft to carry the highly effective centimetric radar.

Mosquito night fighters continued to operate over Europe until the end of the war with a low casualty rate, in spite of the efforts of the Heinkel He 219-equipped units and Messerschmitt 262 jet fighters which were flown at night by pilots from 10./NJG 11. The commander of this unit, Oberleutnant Kurt Welter, claimed perhaps 25 Mosquitos shot down by night and two further Mosquitos by day while flying the Me 262, adding to his previous seven Mosquito kills in "hot-rodded" Bf 109G-6/AS or Fw 190 A-8 fighters. From September 1944 through to May 1945 a total of 92 night-flying Mosquitos of all marks on bombing, target marking, intruder and night fighter operations were lost. As far as can be ascertained, three of his Me 262 claims over Mosquitos coincide with RAF records.

RAF bomber support
From early 1944, the Mosquito also operated in the bomber support role with Bomber Command's 100 Group, their task being to harass the Luftwaffe NachtJagd (night fighters) attacking the bomber streams over Germany. The Mosquito squadrons of 100 Group used several different marks of Mosquitos for different purposes: NF XIXs and NF 30s were used for dedicated night fighter operations providing escort for the bomber streams; F Mk IIs and FB Mk VIs were used for "Flower" (patrolling enemy airfields well ahead of the bomber stream and dropping bombs to keep enemy night fighters on the ground as well as attacking night fighters in the landing pattern) and "Mahmoud" operations. Mahmouds were mounted independently of Bomber Command activity whereby Mosquitos flew to known assembly points for German night fighters (usually visual or radio beacons) and attacked any in the area. B Mk IVs and PR Mk XVIs were used for Electronic Intelligence (ELINT) operations, using special equipment to detect and identify German radar and radio transmissions. Some 258 Luftwaffe night fighters were claimed destroyed by the Group, for the loss of some 70 Mosquitos. The omnipresence of the potent night fighter threat led to what the Luftwaffe crews dubbed "Moskitoschreck" (Mosquito terror), as the German aircrews were never sure when or where they might come under attack from the marauding 100 Group fighters, and indirectly led to a high proportion of aircraft and crew losses from crashes as night fighters hurried in to land to avoid the Mosquito threat, whether real or imagined.

Fighter-bomber versions
Operational experience in its varied roles quickly led to the development of a versatile fighter-bomber version; the FB VI, which first saw service in early 1943. The Mark VI had a strengthened wing for external loads and along with its standard fighter armament could carry two 250 lb bombs in the rear of the bomb bay and two 250 lb bombs under the wings, or eight wing-mounted rockets. Later up-engined versions could carry 500 lb bombs. The FB VI became the most numerous version of the Mosquito (2,292 built), equipping the day bomber 2 Group, the intruder squadrons of Fighter Command and 2nd Tactical Air Force, and the strike wings of Coastal Command, who used the variant as a potent anti-shipping aircraft armed with eight "60 lb" rockets.





One of the higher risk uses of the fighter-bomber Mosquito FB VI was by 21 Sqn., 464 (RAAF) Squadron and 487 (NZ) Squadron of No. 2 Group, 2nd Tactical Air Force in Operation Jericho, a mission to destroy the walls and guards' quarters of Amiens prison to allow members of the French Resistance to escape. In the aftermath of the operation the Mosquito of Group Captain Percy Pickard was shot down.

On 11 April 1944, after a request by Dutch resistance workers, six Mosquito FB VIs of No. 613 (City of Manchester) Squadron made a pinpoint daylight attack at rooftop height on the Kunstzaal Kleykamp Art Gallery in The Hague, Netherlands, which was being used by the Gestapo to store the Dutch Central Population Registry. The first two aircraft dropped high explosive bombs, to "open up" the building, their bombs going in through the doors and windows. The other crews then dropped incendiary bombs, and the records were destroyed. Only persons in the building were killed — nearby civilians in a bread queue were unharmed.

On 21 March 1945, another similar raid, Operation Carthage, again by 21 Sqn., 464(RAAF) Sqn. and 487(NZ) Sqn., involved a very low-level bombing attack on the Gestapo headquarters in the Shellhus, near the centre of Copenhagen, Denmark. The attack had been requested several times by members of the Danish resistance, but was initially deemed too dangerous by the RAF. Twenty Mosquitos were involved, split into three attack waves. They were escorted by 30 RAF Mustangs. The main attack on the Gestapo headquarters caused the death of 55 German soldiers and 47 Danes working for the Gestapo, together with destruction of the Gestapo records in the headquarters. Eight Gestapo prisoners were killed while 18 prisoners escaped. A Mosquito flying in the first wave of the attack struck a tall lamp-post and crashed into a nearby Catholic school (the French school). Mosquitos of the third wave bombed this area by mistake, killing 86 children, 10 nuns, 8 teachers, and 21 other civilians; no civilians had been killed during the main attack. Four Mosquitos were lost and nine pilots/crew members died. The attack saved the lives of many resistance workers as the Gestapo archives and organisation were severely damaged.

The famous RAF 617 squadron (Dambusters), while mainly equipped with Lancaster bombers, also employed the Mosquito for precision target marking by the Master Bomber. According to The Dam Busters, Group Captain Leonard Cheshire developed a dive-bombing method of marking targets in advance of the main squadron, to allow the main bombers to strike from high altitude. Cheshire initially used his own Lancaster for this approach, but switched to the Mosquito as being a more suitable aircraft. These Mosquito missions contributed to Cheshire winning the Victoria Cross in recognition of his sustained courage throughout the war.

Photo reconnaissance
The Mosquito was used throughout the war for photo-reconnaissance missions, using modified day bomber, photo-reconnaissance, and high-altitude, long-range (PR Mk 32 and PR Mk 34) photo-reconnaissance aircraft types. Many of these aircraft missions set altitude and distance records for twin-engined, piston-engined aircraft. The PR.34, a photo reconnaissance version of the Mosquito, could reach 425 mph, placing it among the fastest piston-engined aircraft of World War II.

In 1945, an RAF PR Mk XVI Mosquito of Eastern Air Command operating out of airfields in Burma set a twin-engine record on a single photo-reconnaissance mission covering 2400 mi in 8 hours and 50 minutes. The United States Army Air Forces (USAAF) ordered 120 Mosquitos for photographic reconnaissance, but only 40 were delivered and given the U.S. designation F-8 (six Canadian-built B Mk VII and 34 B Mk XX). Only 16 reached Europe, where 11 were turned over to the RAF and five were sent to Italy. The RAF provided 145 PR Mk XVI aircraft to the Eighth Air Force between February 1944 and the end of the war. These were used for a variety of photographic and night reconnaissance missions.

USAAF
In addition to photo-reconnaissance missions, the USAAF employed its PR Mk XVI Mosquitos as chaff dispensers; as scouts for the heavy bomber force; on "Redstocking" OSS missions at Watton only, 492nd BG never used the Redstocking label; on weather observation flights, and as H2X Mickey platforms by the 802d Reconnaissance Group (Provisional), later renamed the 25th Bomb Group (Reconnaissance). The 25th BG flew 3,246 sorties (this includes B-17, B-24, B-25, B-26, A-26 and Mosquito flights) and lost 29 PR Mk XVIs on operations (this total includes destruction from ground-loops on landing or takeoffs, MIA, KIA, POW).

The 416th NFS in Italy used Mosquito NF.30s during the latter part of the war, claiming one kill.

BOAC
Between 1943 and the end of the war, Mosquitos were used as transport aircraft on a regular route over the North Sea between Leuchars in Scotland and Stockholm. Lockheed Hudsons and Lodestars were also used but these slower aircraft could only fly this route at night or in bad weather to avoid the risk of being shot down. During the long daylight hours of the Northern summer, the Mosquito was the only safe alternative.

Because Sweden was neutral, the aircraft carried civilian markings and were operated by crews who were nominally "civilian employees" of BOAC. They carried small, high value cargoes such as precision ball bearings and machine-tool steel. Occasionally, important passengers were carried in an improvised cabin in the bomb bay, one notable passenger being the physicist Niels Bohr, who was evacuated from Stockholm in 1943. The flight almost ended in tragedy as Bohr did not don his oxygen equipment as instructed, and passed out. He would have died had not the pilot, surmising from Bohr's lack of response to intercom communication that he had lost consciousness, descended to a lower altitude for the remainder of the flight. Bohr's comment was that he had slept like a baby for the entire flight.

In USSR
Mosquitos were in action in the USSR with reconnaissance aircraft periodically operating from Soviet bases on the Kola peninsula to monitor Luftwaffe activities in Norway. A courier mail link between the Soviet and British governments, sometimes transporting VIP passengers was also maintained. The Soviets further made a request to acquire a Mosquito. Mosquito B.IV (DK296) was tested but reports noted that it demanded high flying skills and no further purchases were made.

Post-World War II
Mosquitos flying with the Israeli Air Force saw action during the 1956 Suez Crisis. Although, at the time, the Mosquito was being taken out of service, 13 aircraft of various marks were taken out of storage. An additional 13 TR.33 ex-Fleet Air Arm Mosquitos Mosquitos were purchased from a British scrap dealer in 1954 and delivered via Blackbushe Airport in early 1955. The Dominican Air Force obtained five ex RAF FB.6s in 1948.

Sweden purchased 60 ex-RAF Mk XIX Mosquitos in 1948 to be used as a night fighter under the J 30 designation. The aircraft were assigned to F 1 Hässlö, thereby becoming the first (and only) dedicated night fighter unit of the Swedish Air Force. Its Mosquitos were replaced by jet fighters, de Havilland Venom Mk 51s (designated J 33), in 1953. One-third of the J 30s crashed or broke down during service, mainly due to rudder problems. Swedish Air Force General Björn Bjuggren wrote in his memoirs that mechanical problems in the swivelling nose-mounted radar antenna caused destructive vibrations that broke apart one or two J 30s in the air.

The Belgian Air Force operated 24 Mosquito NF 30s between 1949 and 1956. They were flown by 10 Smaldeel of 1 Wing based at Beauvechain Air Base until they were replaced in the night fighter role by Gloster Meteor NF 11s. MB-24 survives on display in the aviation museum in Brussels. In 1954, the Belgian Air Force also received three Mosquito FB 6s which had been converted to the target tug role.

Spartan Air Services of Ottawa Ontario acquired twelve ex-Royal Air Force Mosquito B.35s in 1955. These were modified by Derby Aviation at Derby (Burnaston) Airport for high altitude aerial survey. After ferrying over the Atlantic, they operated commercially throughout the Americas until the mid-1960s.

Notable pilots

 * Bob Braham – The most highly decorated RAF airman of the Second World War and a top night fighter ace.
 * Eric "Winkle" Brown – the test pilot credited in the Guinness Book of Records as having flown the greatest number of aircraft types in the world, was also the first pilot to land a Mosquito on an aircraft carrier (25 March 1944); previously the only British carrier aircraft had been single-engined and half the weight.
 * Branse Burbridge – the RAF highest scoring Mosquito night fighter ace
 * Leonard Cheshire VC – British No. 617 Squadron RAF commander (and successor to Guy Gibson); one of the most distinguished exponents of precision marking and of the Pathfinders; he later distinguished himself by devoting his life to the care of the disabled and terminally ill and founded the Cheshire Homes. Cheshire's 1944 VC cited his dive over Munich in a Mosquito, enduring "withering" fire for many minutes.
 * Sidney Cotton – Australian spy and photographic reconnaissance pioneer
 * John "Cats Eyes" Cunningham – British night fighter pilot
 * Geoffrey de Havilland Jr – son of the founder and chief test pilot of the firm, carried out the maiden flight of the de Havilland Mosquito.
 * Bill Edrich – English international cricketer, who played against Miller. Graduated from Blenheims to Mosquitos. Was awarded the DFC and became a Squadron Leader.
 * Guy Gibson – British 617 Sqn commander; killed when his Mosquito crashed in the Netherlands while returning to England from a mission.
 * Kirk Kerkorian – Worked as a ferry pilot for Mosquitos from Canada to Britain and elsewhere during World War II. The North Atlantic route was dangerous; the pay was high — $1000 per trip. with a section of the Las Vegas Review-Journal book, The Top 100, citing a 1974 biography by Dial Torgerson Kerkorian, An American Success Story.
 * Keith Miller – Australian international cricketer, regarded by many as the greatest Australian all-rounder. In later life when asked how he dealt with pressure on the cricket field, Miller replied: "Pressure is [having] a Messerschmitt up your arse, playing cricket is not."
 * Bolesław Orliński DFC – famous Polish pilot who flew a Breguet 19 from Warsaw-Tokyo-Warsaw in 1926 and, with a PZL P.24, set a speed record on 28 June 1934. Commanding officer of Polish 305 Squadron, he flew a Mosquito in a mission against German prison camp in Lille and a large German fuel dump at Nomexy.
 * Percy Charles Pickard DFC, DSO, and 2 bars – English Group Captain who starred in film Target for Tonight early in the war. Later became Group Captain and was shot down and killed during Operation Jericho, the raid on Amiens Prison.
 * Erik Hazelhoff Roelfzema – Dutch resistance fighter and secret agent flew 72 sorties for No. 139 Squadron RAF and wrote Soldier of Orange.
 * Kenneth Wolstenholme – a Flight Lieutenant in No. 105 Squadron RAF. He later became the presenter and commentator on the BBC Match of the Day football programme.  He spoke the widely repeated words "some people are on the pitch ... they think it's all over... it is now" as Geoff Hurst scored the fourth goal in England's 4-2 World Cup Final win over West Germany in 1966.
 * John Wooldridge – composer of film music, studied music under Sibelius and was a friend and contemporary of William Walton. Had been one of Guy Gibson's flight commanders. Crossed Atlantic in Mosquito in 5hrs, 46 minutes.