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. 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