Delivery of the F-35 programme in terms of performance, time and cost remains under continuous assessment as part of the Ministry of Defence's ongoing process of assurance. Overall, the F-35 programme continues to make steady progress. The development Flight Test programme is on target and in August 2013, the F-35B underwent a successful second set of carrier trials aboard the USS Wasp.
The UK F-35 programme has taken delivery of its first three aircraft on schedule, which are currently based at Eglin Air Force Base, Florida. An order was placed for a fourth UK aircraft in September 2013. The UK programme remains on track to deliver Initial Operating Capability in December 2018.