Eight thousand hours, or one complete lifetime of durability testing is now complete on the F-35 conventional takeoff and landing (CTOL) variant.

Durability testing of the CTOL airframe to 8,000 hours was completed ahead of schedule, proving the airframe is able to handle a variety of flying conditions it will experience when in service. Work continues on schedule for proving the aircraft for up to two lifetimes or 16,000 hours.
The 350 tonne structural test rig at our Brough facility was purposely built to ‘fly’ the F-35 through a series of flight scenarios.  Over 20 miles of wiring, 2,500 strain gauges and 160 loading actuators subject the aircraft to a range of loads that it would typically encounter in actual flight.
We are also contracted for the static and fatigue testing for horizontal tails and fatigue testing on vertical tail.
Fifteen per cent of F-35 Lightning II work is carried out in the UK and over 130 British companies contribute to the supply chain. It is worth over £1Bn to UK industry each year and will support around 25,000 British jobs over the next 25 years.

BAE press release