where was he posted as an initial fighter?
No. 11 Squadron.
Albert Ball
On 7 May 1916, Ball was posted to No. 11 Squadron, which operated a mix of fighters including Bristol Scouts, Nieuport 16s, and Royal Aircraft Factory F.E.2b "pushers". 
who was albert ball? An English fighter pilot during the First World War. where did he take his flight training? At Mousehold Heath.
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Albert Ball [SEP] Initial fighter posting
His singularity in dress extended to his habit of flying without a helmet and goggles, and he wore his thick black hair longer than regulations generally permitted. While flying a Bristol Scout on 16 May 1916, Ball scored his first aerial victory, driving down a German reconnaissance aircraft. He then switched to Nieuports, bringing down two LVGs on 29 May and a Fokker Eindecker on 1 June. On 25 June he became a balloon buster and an ace by destroying an observation balloon with phosphor bombs. During the month he had written to his parents admonishing them to try and "take it well" if he was killed, "for men tons better than I go in hundreds every day".