Fighter jets face more Pentagon safety rules

The Pentagon has issued further safety procedures for its most advanced fighter jet after pilots complained of oxygen shortages during flights.



The rules include limiting the distance F-22 planes can travel from airstrips.



Defence Secretary Leon Panetta did not rule out grounding the jets again if necessary.



The Air Force banned its F-22s from flying for four months last year, to investigate the oxygen-deficit problem, but its cause remains unclear.



Panetta has also asked for a back-up oxygen system to be put into the planes, with the first of these due to be installed in December.



The new safety precautions mean the F-22 will have to abandon long-distance air patrol missions in Alaska, the Pentagon said.



The jet has never been used in combat.