Despite these challenges, the Air Force did take an active part in the defence of the realm in the Hejaz-Nejd War between Hejaz and the Sultanate of Nejd. Ibn Saud attacked Ta'if on 29 August 1924 and the Ikhwan quickly proved more than a match for the Hejaz forces. The Air Force was called in to support the outnumbered Hejaz troops. During the Battle of Mecca, a lone pilot, a White Russian émigré named Shirkoff, undertook reconnaissance sorties twice daily with an Arab observer. The airmen also undertook bombing missions by the simple expedient of throwing shells or grenades over the side of the aircraft. A bombing raid took place on Mecca on 3 January 1925. These makeshift bombs were also a huge hazard, killing Shirkoff and two crew members on 18 January during the Battle of Jeddah when their DH.9C aircraft exploded and crashed while flying over an enemy camp. These proved to be the Air Force's only fatalities while flying in action. However, crashes had destroyed all but one of the fleet's aircraft by the end of May 1925. The arrival of six second-hand DH.9 aircraft with twelve Lewis machine guns, 120 cases of ammunition and 500 bombs on 20 August, along with an influx of German pilots and crew provided by Steffen &amp; Heyman of Berlin gave the force a much needed boost but it was insufficient to stem the tide and, when Ali bin Hussein capitulated on 21 December 1925, the kingdom ceased to exist as an independent entity.