LOCKHEEDMARTIN has replaced one of the Pratt &Whitney F119s in the first F-22 after the engine suffered minor foreign-object damage (FOD) during ground runs. The incident is likely to delay the maiden flight of the Lockheed Martin/Boeing F-22 until early July.
Minor impact damage to the three fan stages and first compressor rotor on the right-hand F119 was discovered during post-test boroscope inspection following the first day of engine runs carried out at Lockheed Martin's plant in Marietta, Georgia. Aircraft-generated FOD is suspected as the cause.
The fan blades have been repaired by blending out the damage, but action to be taken on the compressor rotor has yet to be determined. The engine, meanwhile, has been replaced by a spare F119 and ground runs were scheduled to resume by 18 June. All airframe cavities have been boroscope inspected and recleaned.
One week of engine runs, followed by electromagnetic-interference testing, four days of taxi tests and a 48h check-out period, are planned before the first flight. This was scheduled for the end of May, but was delayed first by a fuel leak, then by overheating of the auxiliary power unit (APU).The fuel leak was traced to structure added during assembly to strengthen the composite forward-fuselage fuel tank. APU overheating was traced to a closed vent line.
Three flights are planned before the F-22 is grounded for 12 weeks for finishing and further tests. An additional eight or nine flights will then take place to clear the limited performance envelope required for the ferry flight to the test centre at Edwards AFB, California.