Almost one year ago today (on Jan. 20, 2012), citing the progress the F-35B STOVL (Short take off vertical landing) variant made in 2011, Secretary of Defense Leon Panetta rescinded probation for the F-35B, about one year ahead of schedule.

The STOVL had come close to be scrapped after technical issues along with massive cost over runs had put the monumentally complex version at risk.

However, when it looked like it had solved all those problems that had jeopardized its survival, the STOVL (Short Take Off Vertical Landing) version of the F-35 Lightning II 5th generation fighter plane, found another possibly major issue to face.

The production of the F-35 Joint Strike Fighter – the world’s most sophisticated and expensive combat aircraft – has been derailed after engineers discovered that the jet’s fuel tank could explode if struck by lightning. The disclosure is a major setback for the aircraft, also known as the Lightning II, which is due to enter service with both the RAF and the Royal Navy by 2018. Attempts to increase fuel efficiency by reducing the jet’s weight have also made it more vulnerable to enemy attack than the generation of aircraft it was supposed to replace. The damaging findings were disclosed in a Pentagon document which revealed that a fault within the JSF’s fuel tank could potentially lead to catastrophic explosion if the aircraft was struck by lightning in a thunderstorm. The report from the Pentagon’s Operational Test and Evaluation Office states that all test flying within 25 miles of thunderstorms is “not permitted” until a device in the fuel tank which maintains correct oxygen levels is redesigned.