F-35s Get Go Ahead To Return To The Skies

The fleet of F-35 jets, grounded last week after a crack was found in an engine blade, has been given the all-clear to resume flying.

A crack measuring 0.6 of an inch was found during a routine inspection on a test plane at Edwards Air Force base in California.

All 51 jets were grounded.

Engineers conducted tests and gathered data from the damaged blade this week. These included carefully opening up the blade and then the engineers compared that with examinations carried out on control blades.

As Sky News reported on Wednesday, no further cracks were found in blades belonging to other planes in the fleet.

The crack was discovered on a test aircraft - unlike the training planes these jets are subjected to extreme temperatures and performance checks.

This puts additional stress and wear on the engine. However it has not been possible to pinpoint exactly when or why the crack occurred.

The F-35 is the Pentagon's most expensive weapons programme, with a total estimated cost of nearly $400bn (£262bn).

The Pentagon has plans to buy more than 2,400 F-35s, but some members of Congress are hesitant because of the hefty price tag.

The UK has ordered 48 F-35s of which only two have so far been delivered for training.

They will fly off the Royal Navy's new Queen Elizabeth carrier once it is built in 2018. Britain has also invested in the development of the jet.