"This heavy ‘C’ check enters NASA's DC-8-72 into the LUMP scheme of maintenance that provides a highly efficient means for managing airframe and subsystems inspections."
Source: NASA's DC-8-72 project manager Frank Cutler, in regards to the selection of AerSale, Inc. to provide “C” check maintenance services for one of the agency's Airborne Science Program workhorses – the DC-8-72 flying laboratory. The aircraft has been flown to AerSale’s maintenance facility in Roswell, New Mexico, where it is to undergo major inspection and maintenance servicing.