During inspections in 1995 and 1996, cracks at the WS23 location were found on many aircraft, most of them in line with updated predictions from 1993. However, two of these were classified as "near-critical" size, well beyond predictions. In August 1998, Grumman produced a new plan to address these issues and increase life span to 16,000 hours. This resulted in the "HOG UP" program, which commenced in 1999. Over time, additional aspects were added to HOG UP, including new fuel bladders, changes to the flight control system, and inspections of the engine nacelles. In 2001, the cracks were reclassified as "critical", which meant they were considered repairs and not upgrades, which allowed bypassing normal acquisition channels for more rapid implementation.