The RAF Advanced Air Striking Force (AASF) 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 (Air officer commanding Air Vice-Marshal Charles Blount) came under the command of British Air Forces in France (Air Vice-Marshal Arthur Barratt) 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 instead, attacks on German military forces and their communications were made.
The Battle of France began with the German invasion of the Low Countries on 10 May 1940. The Battle squadrons suffered 40 per cent losses on 10 May, 100 per cent on 11 May and 63 per cent on 12 May. In 48 hours the number of operational AASF bombers fell from 135 to 72. On 14 May the AASF made a maximum effort, 63 Battles and eight Bristol Blenheims attacked targets near Sedan. More than half the bombers were lost, bringing AASF losses to 75 per cent. The remaining bombers began to operate at night and periodically by day, sometimes with fighter escorts.
From 10 May to the end of the month, the AASF lost 119 Battle crews killed and 100 aircraft. Experience, better tactics and periods of bad weather from 15 May to 5 June led to losses of 0.5 per cent, albeit with a similar reduction in effectiveness. On 14 June, the remaining Battles returned to Britain; the Hurricane squadrons returned on 18 June and rejoined Fighter Command. The AASF was dissolved on 26 June, the Battles returning to 1 Group, Bomber Command, to prepare for operations against a German invasion, along with the rest of the Royal Air Force.
Background
1930s Anglo-French air policy
Once British rearmament began, the air policy of the British government was to have air defences sufficient to defeat an attack and an offensive force equal to that of the . With no land border to defend, British resources had been concentrated on radar stations, anti-aircraft guns and increasing the number of the most modern fighter aircraft. If Germany attacked, the British intended to take the war to the Germans by attacking strategically important targets with its heavy bombers, types unsuitable for operations in direct support of land forces. Implementation of the policy required a considerable number of first-class fighter aircraft to defeat an attacker and bombers to destroy ground targets.
In 1938 the RAF expansion programme was intended to provide means for the air defence of Britain and for counter-offensive operations against Germany. Army co-operation received few resources and no plans were made for RAF participation in mass land operations or the dispatch abroad of large expeditionary air forces. The Western Plan was devised by the Air Ministry for mobilisation and the deployment of squadrons to their wartime airfields. Provision was made for the immediate dispatch of an Advanced Air Striking Force of ten squadrons to France, followed by a second echelon of ten more. Refuelling facilities were also planned for other squadrons, the arrangements for transport and servicing being co-ordinated with the army; thought was also given to basing squadrons in Belgium if it was invaded by Germany.
In February 1939, the British Cabinet had authorised joint planning with the French and preferably with Belgium and the Netherlands in case of war with Germany, Italy and Japan. Two weeks before the first meeting, Germany occupied the rump of Czechoslovakia; war preparations took on a new urgency and staff conversations began on 29 March 1939. Agreement was reached with France to base the AASF on French airfields but only to bring them closer to their intended targets in Germany, until longer-range types became available. French strategy emphasised the defence of the national territory and Allied efforts were expected to give equal emphasis but the British refused to stake everything on the success of a defensive campaign against the Germans in France. The different circumstances of the two countries led the French to rely on a mass land army, with air defence a secondary concern, the was hampered in the late 1930s by the slow progress of its re-equipment, lacking anti-aircraft guns, sufficient fighter aircraft and the means to detect and track enemy aircraft. Observation services relied on civilian telephones and in October 1939, the had only which were considered (obsolete).
Lack of aircraft led the French to advocate a bombing policy of tactical co-operation with the armies, attacking German forces and communications in the front line, rather than the strategic bombing of Germany, for fear of retaliation. From the spring of 1939, arrangements were made for the reception of the AASF, the defence of British bases in France, bombing policy in support of ground forces confronting a German attack in the Benelux countries, and operations against the . A supply of British bombs was dumped near Reims, disguised as a sale to the . Discussion of strategic air operations against the German war economy was delayed because the British did not expect to begin such operations as soon as war was declared and because the French had no bombers capable of them. In the last days of peace, the Cabinet limited air bombardment strictly to military objectives which were narrowly defined and a joint declaration was issued concerning the policy of following of the rules of war pertaining to poison gas, submarine warfare and air attacks on merchant ships to avoid provoking the Germans while the Anglo-French air forces were being built up.
August 1939
On 24 August 1939, the British government gave orders for the armed forces partially to mobilise and on 2 September No. 1 Group RAF (Air Vice-Marshal Patrick Playfair) sent its ten Fairey Battle day-bomber squadrons to France according to plans made by the British and French earlier in the year. The group was the first echelon of the AASF and flew from RAF Abingdon, RAF Harwell, RAF Benson, RAF Boscombe Down and RAF Bicester. Group headquarters became the AASF when the order to move to France was received and the home station HQs became 71, 72 and 74–76 Wings. The Bristol Blenheims of No. 2 Group RAF were to become the second echelon as 70, 79 and 81–83 Wings, flying from RAF Upper Heyford, RAF Wattisham, RAF Watton, RAF West Raynham and RAF Wyton; 70 Wing with 18 and 57 squadrons was converting from Battles to Blenheims and intended for the Air Component once the re-equipment was complete. On 3 September, as the British government declared war on Germany; the AASF Battle squadrons were getting used to their French airfields, which were somewhat rudimentary compared to their well-developed Bomber Command stations, some having to wait for the French to deliver aviation fuel.
September Strategic bombing operations did not take place as the and Allied strategic bombers observed a tacit truce. The French tried to divert German resources from their Invasion of Poland with the Saar Offensive (7–16 September), in which the Battle squadrons were to participate. The main bases were too far inside Germany but airstrips, supply dumps and reserves would be well within the range of the Battles. The British and French governments feared that they had more to lose by courting German retaliation but this deprived the Battle squadrons of a chance to test their equipment and tactics. The preparations did establish that Battles would attack targets within of the front line, including fleeting opportunities, much against the wishes of Group Captain John Slessor, a former director of plans at the Air Ministry, who stressed that the Battle crews were not trained for close support. Other officers thought that "...it is about as far as the Battle will be able to get with a return ticket". Playfair had the fuselage fuel tank removed from AASF Battles and the bomb bays were to be modified to carry anti-personnel bombs, once the equipment arrived in November.
Battle reconnaissances
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 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, at first, then . 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 (). 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 (), 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 Saarbrücken 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, 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 which were already flying the type.
AASF tactical changes