Safety

U.S. Air Force Grounds Older F-15s Again

posted: 29 November 2007 12:23 pm ET

: An F-15C Aggressor from the 65th Aggressor Squadron at Nellis Air Force Base, Nev., flies over a mountain range on a July 25, 2007 refueling mission at the Red Flag-Alaska exercises. On Nov. 28, 2007, all U.S. Air Force Air Combat Command F-15As, F-15Bs, F-15Cs and F-15Ds were grounded for the second time in less than a month when the investigation into the crash of an F-15C on Nov. 2 found indications of structural failure in the upper longerons of that aircraft. Also, cracks were found in the upper longerons of two other F-15Cs that were inspected subsequent to the crash. Credit: U.S. Air Force photo/Capt. Tana Stevenson

LANGLEY AIR FORCE BASE, Va. (AFPN) -- For the second time this month, the commander of U.S. Air Force Air Combat Command (ACC) has directed a fleet-wide inspection of all A-through-D-model F-15s in ACC's inventory.

The directive follows Nov. 27 findings stemming from the investigation of an F-15C mishap on Nov. 2 that resulted in the loss of the aircraft. Based on the new findings, all A-through-D-model F-15s will be stood down for additional inspections and possible repair actions, according to Air Force Print News.

Gen. John Corley, the ACC commander, also recommended the stand-down of all other similar-model aircraft in other Air Force major commands, including those under the operational control of U.S. combatant commanders.

Action by Gen. Corley to ground the ACC's older F-15s came just two days after he released the command's F-15 fleet to resume flight operations following the initial grounding on Nov. 3. The U.S. Air Force Accident Investigation Board (AIB) convened for the Nov. 2 accident published its new findings after the initial release decision was made.

The new AIB findings indicate possible fleet-wide airworthiness problems with F-15A, F-15B, F-15C and F-15D aircraft. These findings, based on a metallurgical analysis of the mishap aircraft, have drawn attention to the upper longerons near the F-15's canopy. These appear to have cracked and failed. The longerons are major structural components that run along the length and side of the aircraft.

Although the longeron area was covered in general by previous inspections as a result of the Nov. 2 mishap, the Nov. 27 findings have convinced technical experts at the Warner Robins Air Logistics Center in Georgia to recommend a specific inspection technique for the suspect area.

Manufacturer simulations have indicated that a catastrophic failure could result in this particular area. In addition, cracks were discovered along the same longeron area during two recent inspections of F-15Cs. These aircraft were immediately grounded as a result of the inspection findings and are awaiting further engineering instructions.

Because of the latest findings from the Nov. 2 accident, ACC believes it is necessary to stand-down its F-15As, F-15Bs, F-15Cs and F-15Ds until more detailed and tailored inspections can be made of the focus areas in the upper longerons of each aircraft.

Air Combat Command continues to work with the Air National Guard, the Air Force Reserve and sister major commands in Europe and the Pacific, as well as joint and coalition partners, to ensure mission coverage.

The stand-down does not affect the F-15E. The duration of the stand-down is pending the completion of required inspections and any necessary repair actions.