page_title: RAF Advanced Air Striking Force
section_title: Battle reconnaissances
hierarchical_section_title: RAF Advanced Air Striking Force / Background / September / Battle reconnaissances
caption_attribution_description: English: The Course Setting Bomb Sight, labeled as a Mk. IX but likely a Mk. VII, installed in the bottom of a Fairey Battle light bomber. The bomb aimer is sighting through the backsights (white rings just in front of him) and past the foresights (white pinheads just visible against the armoured cable running on the bulkhead, looking like a cable clip). He holds the bomb release switch in his right hand, and would press the button when the target passes through the line defined by the two sets of sights. This image shows a number of the main features of the sight. At the rear of the device, near the bottom of the image, is the vertical cylinder of the compass assembly. The horizontal metal section in front of the compass assembly, roughly triangular, is the "airspeed drum", used to set the aircraft's airspeed via the large knob on the right side of the case, directly under the bomb aimer's hand. Extending from the front of the airspeed drum is the airspeed bar and windspeed assembly. In this case the airspeed has been set to its minimum value, so the windspeed assembly is lying directly against the housing and is not clearly visible. This also explains the almost vertical angle formed between the sights; with this airspeed setting the bombs would not travel forward very far during the drop. Looking carefully, one can see the "wind bar" at the top of the windspeed assembly, the black metal bar lying almost at right angles to the rest of the bomb sight. Turning the wind speed knob on the end of the bar (not visible here, it's on the other side of the bar) would push the entire drift bar to the right to dial-in increasing correction for a wind blowing from the right side of the aircraft. The long striped wires above this assembly form the drift bar, which indicates which direction the aircraft should fly to correct for wind drift. In this case the drift bar is pointed very slightly to the bomb aimer's left, accounting for a wind from port. Secondary details are also visible. The grey disk on the bottom of the compass assembly is the compass corrector, which reduces the effect of stray magnetic fields from the aircraft body. The small grey knob directly above the airspeed setting knob is used to set the "trail", the distance that the bomb will fall behind the aircraft when it reaches terminal velocity. Just to the right of this (in the photograph) is a large horizontal ring that makes up the moving target assembly (or "fourth vector"). To the right of the air speed drum are two of three silver coloured bolts of the flexible mounting system, which is used to level the bombsight prior to use. The small beads used for timing can just be seen on the drift wires. At the front, on the very top-right of the image, is the scale on the auxiliary drift bar, which is used to make quick measurements of wind drift. The Battle was supplied with a number of different bombsights for use at different altitudes. They could be exchanged by unscrewing the silver knob on the right side of the photo just to the right of the windspeed assembly, and then sliding the entire bombsight and mounting up and out. The original label on this photograph states that the bombsight is a Mk. IX model. However, this model was designed for high-speed aircraft like the B-25 and Mosquito. It is much more likely that this is a mis-labeled Mk. VII, the primary pre-war model that would have equipped the Battle in service. The differences between the two models are largely limited to the scales on the drift and height bars to account for faster speeds and higher altitudes. The two are identical to the eye.
context_page_description: The RAF Advanced Air Striking Force comprised the light bombers of 1 Group RAF Bomber Command, which took part in the Battle of France during the Second World War. Before hostilities began, it had been agreed between the United Kingdom and France that in case of war, the short-range aircraft of Bomber Command would move to French airfields to operate against targets in Nazi Germany. The AASF was formed on 24 August 1939 from the ten squadrons of Fairey Battle light bombers of 1 Group under the command of Air Vice-Marshal Patrick Playfair and was dispatched to airfields in the Rheims area on 2 September 1939.
  The AASF was answerable to the Air Ministry and independent of the British Expeditionary Force. For unity of command, the AASF and the Air Component of the BEF, came under the command of British Air Forces in France on 15 January 1940. Using the bombers for attacks on strategic targets in Germany was set aside due to Anglo-French reluctance to provoke German retaliation and attacks on German military forces and their communications were substituted.
  The Battle of France began with the German invasion of the Low Countries on 10 May 1940.
context_section_description: Neither the French nor the British wanted the AASF to sit idle and the Battles began to conduct "high-altitude", formation, photographic reconnaissance sorties, to map the German front line but the Battle had a service ceiling of only 25,000 ft (7,620 m) and needed to be much lower for formation flying. Battle sorties began on the morning of 10 September, three aircraft of 150 Squadron flying inside Allied lines and photographing obliquely. On 19 September the Battles began to fly beyond the front line, 10 mi (16 km) at first, then 20 mi (32 km). Playfair, mindful of the risk, tried to time sorties to coincide with French fighter operations in the vicinity and wanted close escorts if German fighters were around. Three Battles from 103 Squadron and three from 218 Squadron reconnoitred on 17 September, the Battles encountering intermittent anti-aircraft fire (FlaK). Bad weather led to a two-day lull, then on 20 September, three Battles from 88 Squadron west of Saarbrücken were attacked by three Messerschmitt Bf 109Ds, which shot down two of the Battles, whose defensive fire was ineffective. One Battle pilot crash-landed and his aircraft caught fire, killing the observer and gunner; the other Battle crashed the same way and the third Battle was hit in its fuel tanks and incinerated the crew.
  Playfair concluded that Battles should receive an escort anywhere near the front line but the Air Ministry rejected the claim that more fighters were necessary and he had to ask the French instead. The Chief of Staff of the French Air Force (Chef d'état-major de l'Armée de l'air), Général d'Armée Aérienne Joseph Vuillemin, was short of fighters but promised to help, provided the British helped themselves. At a meeting on 28 September, the British representative repeated the claim that tight formation-flying and collective firepower obviated the need for escorts and Vuillemin cancelled French co-operation. Two days later, five Battles from 150 Squadron on reconnaissance near Saarbrucken and Merzig, were attacked by eight Bf 109Es. The Battles closed up but four were shot down, most in flames. The surviving Battle pilot ran for home and crashed on landing but saved his crew. The squadron immediately fitted its aircraft with an extra rear-facing gun in the bomb-aiming position against attacks from below and behind; in England the Air Ministry blamed the Battle, rather than faulty tactics and equipment and declared it obsolete. For protection against fighter attack, 85 lb (39 kg) of armour for each aircraft was rushed to France and 15 and 40 squadrons returned to Britain to convert to Blenheims, being replaced by 114 and 139 squadrons, already equipped with Blenheims.
caption: Observer facing forward with a Mk VII bombsight
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