From AvWeb
The Air Force has grounded 116 C-130Hs, more than 20 percent of the fleet, after it was determined that inscriptions scratched in the propellers documenting inspections for cracks actually caused cracks. “The process used to engrave serial numbers on the propellers likely contributed to cracks that are being found on the C-130Hs,” Maj. Beau Downey, an Air Force spokesperson, told Defense One. “That process, which involved an electric arc pen to incise digits into the surface of the metal, was stopped about six months ago and will not be used going forward.”Some of the aircraft have been returned to service but the Air Force won’t say how many. The cracks and aircraft groundings came to light in October, but the cause wasn’t released until this week. Downey said the Air Force is studying how the cracks spread from the inscriptions and is working on getting the Hercs back on the line. “This will be an incremental process based on operational priority and our focus remains the safety of our crews.”