C-130s Slowly Returning To Service

Team Infidel

Forum Spin Doctor
Air Force Times
March 23, 2009
Pg. 13
By Bruce Rolfsen
Hundreds of C-130s with potentially faulty nuts inside their wings should be fixed and back in the air in about eight weeks, according to a timetable laid out by an Air Force maintenance expert.
Most of the service’s 597 Hercules have been parked since March 3 when Materiel Command ordered all of the transports inspected for the problem steel nuts, which connect the wings with the fuselage. The only C-130s flying were those that passed inspection or were quickly repaired.
By March 12, inspections reached about 90 percent of the fleet, said Terry May, who oversees maintenance for the C-130 fleet as director of the 330th Aircraft Sustainment Group at Robins Air Logistics Center, Ga. Most of the planes not yet checked were out of service for overhauls or other maintenance work.
Of the approximately 540 planes inspected, 266 C-130s had potentially faulty nuts, May said. The other inspected planes did not have the nuts and were allowed back in the air.
The nuts attach the “outer wing” to the wing box, said May. Each wing has 15 nuts inside the lower part of the joint, which is just to the outside of the inboard engines, he said.
Two airmen need about two hours to inspect the nuts on each wing. Squadron-level maintainers using a torque wrench can replace the nuts, which measure about 1¼ inches across with a ¾-inch hole and can be easily identified by their unique “stepped” shape.
The nuts, May said, could have been on planes since at least 2004, the same year that inspectors found four cracked nuts on a C-130 at Hill Air Force Base, Utah, but concluded the problem was isolated.
A routine replacement of the nuts during a depot-level overhaul March 1 at Robins again turned up cracked nuts, May said. By March 3, engineers and others concluded hydrogen embrittlement during manufacturing probably caused the cracks. The steel nuts become fragile and susceptible to cracking after being exposed to hydrogen.
The Defense Logistics Agency is investigating the circumstances that led to the cracks and will determine if the nuts met specifications, according to May. Citing the ongoing inquiry, May declined to name the manufacturer.
After the March 1 discovery, no one knew for sure how many or which planes had the nuts, May said. All nuts on C-130s get replaced about every five years when the planes go through a depot overhaul. Newer C-130Js that haven’t been overhauled were also checked after builder Lockheed Martin advised it might have purchased and installed some of the nuts.
Quick response time
C-130 maintainers didn’t waste any time getting to work after they received the March 3 order.
“The 317th Airlift Group received the direction to inspect our 33 C-130H1 aircraft on Wednesday night, and within 12 hours, we inspected all of our airplanes at Dyess Air Force Base,” group commander Col. Bernard E. Mater said from the Texas installation.
By March 9, the 317th flight schedule was back to normal.
“While these kinds of maintenance actions are rare, [maintainers] took the task in stride so the Fightin’ 317 could fly this week’s planned flight operations,” Mater said.
Now, the challenge for the Air Force is getting enough nuts that aren’t defective.
The service quickly shipped its stockpile of acceptable nuts to squadrons flying Iraq and Afghanistan sorties and other squadrons with high-priority missions such as special operations, May said.
The Robins center is now working with the Defense Logistics Agency to purchase enough nuts to repair the planes; the nuts should be on hand in about two months.
 
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