"On Jul. 11, 2012, F-35B BK-2 took the air from NAS Fort Worth JRB for the aircraft’s inaugural flight. Piloted by Lockheed Martin test pilot Bill Gigliotti, the second F-35 produced for the United Kingdom (serial number ZM136), flew a 1.4-hour maiden flight....
...BK1, the UK’s first of three development aircraft (serial ZM135), made its inaugural test flight on Apr. 13."
Lockheed Martin test pilot Bill Gigliotti flew F-35B BF-17(US Navy Bureau Number 168313) on its inaugural 1.2-hour flight on 24 July 2012 from NAS Fort Worth JRB, Texas. The aircraft will be assigned to VMFAT-501 at Eglin AFB, Florida
Btw, BF-18 is one of three new Mission Systems jets being added this year and early next year (BF-17/18 and CF-8 ). These should help to speed up the Missions Systems testing considerably.
The program plans to provide three more operational test aircraft from production lots 3 and 4 to the mission systems test fleet – F-35B aircraft BF-17 and BF-18 (in late 2012) and F-35C aircraft CF-8 (in early 2013).