Article Posted on : - May 06, 2011

US Air Force F-22 Raptor

WASHINGTON (BNS): The US Air Force has grounded its fleet of Lockheed Martin built F-22 Raptors citing concerns over the fighter jets' oxygen-generation system.

According to media reports, Gen. William Fraser, commander of US Air Combat Command, ordered a stand-down of the 165-plane fleet on Tuesday. It is not immediately known how long the Raptors will be out of service.

An investigation into the Raptors� On-Board Oxygen Generating System (OBOGS) was launched in the wake of an F-22 crash in November last year in Alaska. Until the stand-down, Raptor sorties had been restricted to an altitude of 25,000 feet or below for training missions because of the potential malfunctions, reports said.

The Raptor is the premier US fighter, with cutting-edge "fifth-generation" features, including shapes, materials and propulsion systems designed to make it appear as small as a swallow on enemy radar screens.