USAF Grounds 123 Hercules Aircraft to Inspect Wing Joints

US Air Mobility Command has ordered the grounding 123 C-130 Hercules aircraft to inspect them for signs of cracking on the “rainbow fitting” joints that hold the aircraft’s wings to the top of the fuselage.

“Gen. Maryanne Miller, Air Mobility Command commander, ordered the temporary removal of 123 of 450 Total Force C-130 Hercules from service on August 7, after ‘atypical cracks’ were discovered on the lower center wing joint or ‘rainbow fitting’ during programmed depot maintenance,” Air Mobility Command said in a statement Wednesday.

"In consultation with aircraft maintenance and engineering experts, Gen. Miller directed an immediate time compliance technical order inspection to identify and correct any cracking to ensure airworthiness of these C-130 aircraft," the statement said, adding that "aircraft that are inspected and determined to have no cracking will be immediately returned to service."

 In accordance with the Time Compliance Technical Order (TCTO), in-depth visual and modified non-destructive inspections of the wing box will be conducted on affected C-130H and J-model aircraft that have not received the extended service life center wing box and have greater than 15,000 equivalent flight hours.

Aircraft that are inspected and determined to have no cracking will be immediately returned to service, the statement further said.