Northrop Grumman will conclude a three-year structural fatigue testing of a C-2A Greyhound at the end of this month as part of a programme to extend the carrier onboard delivery aircraft's operational life to 2020.

The C-2A's airframe has undergone continuous fatigue tests at Northrop Grumman's Bethpage plant and, by the end of this month, will have amassed 28,000 effective flight hours. The test article, the sixteenth of a second batch of 39 C-2As built between 1984 and 1990, had 4,000 flight hours before the start of static testing in 1996.

Programme director John Stark says the aim of the test is to extend the C-2A's airframe life from 10,000h to 15,000h. This would be sufficient to keep the transport flying until 2020, when the US Navy hopes to field a replacement common support aircraft.

The highest time reached by an aircraft in the fleet is 6,100h. Some other C-2As have completed 13,000 landings from a maximum permissible number of 15,000. The first batch of 19, built in the 1960s, retired in 1987 with an average airframe life of 9,000h.

Testing includes simulated arrester hook landings, catapult launches and in-flight cycling of the aircraft's rear loading ramp.

Further testing is under way on a separate C-2A wing, including repeated heating of the lower wing surface to simulate hot engines. When the wings are folded, the lower skins facing the fuselage are close to the engine nacelles, which causes heat-induced compressive loads, and this reduces their lives, according to Stark.

Once testing is complete, the C-2A will be removed from the rig and inspected for fatigue cracks before being cut up. Using test data accumulated over the past three years, the USN plans a C-2A structural life extension programme.

Source: Flight International