The C-2 Greyhound, a derivative of the E-2 Hawkeye, shares wings and power plants with the E-2, but has a widened fuselage with a rear loading ramp. The first of two prototypes flew in 1964. After successful testing, Grumman began production of the aircraft in 1965. The C-2 replaced the piston-engined Grumman C-1 Trader in the COD role. The original C-2A aircraft were overhauled to extend their operational life in 1973.
Powered by two Allison T56 turboprop engines, the C-2A can deliver up to 10,000 pounds (4,500 kg) of cargo, passengers or both. It can also carry litter patients in medical evacuation missions. A cage system or transport stand restrains cargo during carrier launch and landing. The large aft cargo ramp and door and a powered winch allow straight-in rear cargo loading and unloading for fast turnaround. The Greyhound's ability to airdrop supplies and personnel, fold its wings, and generate power for engine starting and other uses provide an operational versatility found in no other cargo aircraft.
The C-2 has four vertical stabilizers, of which three are fitted with rudders. A single vertical stabilizer large enough for adequate directional control would have made the aircraft too tall to fit on an aircraft carrier hangar deck. The four-stabilizer configuration has the advantage of placing the outboard rudder surfaces directly in line with the propeller wash, providing effective yaw control down to low airspeeds, such as during takeoff and landing. In 1984, the Navy ordered 39 new C-2A aircraft to replace older airframes. Dubbed the Reprocured C-2A or C-2A(R) due to the similarity to the original, the new aircraft has airframe improvements and better avionics. The older C-2As were phased out in 1987, and the last of the new models was delivered in 1990.
The 36 C-2A(R)s underwent a critical Service Life Extension Program (SLEP). The C-2A(R)'s lifespan was 10,000 hours, or 15,000 carrier landings; plans require the C-2A to perform its mission supporting battle group operational readiness through 2015. The lower landing limit was approaching for most airframes, and the SLEP will increase their projected life to 15,000 hours or 36,000 landings. Once complete, the SLEP will allow the 36 aircraft to operate until 2027. The SLEP includes structural improvements to the center wing, an eight-bladed NP2000 propeller, navigational upgrades including the addition of GPS and the dual CAINS II Navigation System, the addition of crash-survivable flight incident recorders, and a Ground Proximity Warning System. The first upgraded C-2A(R) left NAVAIR Depot North Island on 12 September 2005, after sitting on the ground for three and a half years while the SLEP was developed and installed. All aircraft will receive SLEP by 2015.
In November 2008, the company also obtained a $37M contract for the maintenance, logistics and aviation administration services over five years for the C-2A fleet assigned to VX-20 test and evaluation squadron at Patuxent River. Northrop Grumman is currently working on an upgraded C-2 version, and has offered to modernize the fleet with components common to the E-2D Hawkeye.
The C-2 competed with the V-22 Osprey for use as the future carrier onboard delivery (COD) aircraft. Northrop Grumman proposed modernizing the C-2 by installing the same wings, glass cockpit, and engines as the E-2D Advanced Hawkeye in two phases. The first would replace the engines and avionics, and the second would replace the wing structures. Installing the Rolls Royce T56-427A engines would cut fuel consumption by 13-15 percent with the same 8-bladed propeller; this would enable take offs with a 10,000-pound (4,500 kg) payload in 125 °F (52 °C) degree heat and a range in excess of 1,400 nmi (1,600 mi; 2,600 km), similar performance by the C-2A requires engine temperatures at 70 °F (21 °C), requiring trading fuel for payload. Adopting the E-2D's cockpit would deliver a 10 percent savings on lifetime logistical support. One of the Greyhound's most important features is its internal volume of 860 cubic feet (24 m3) of cargo space. Northrop Grumman stated that their approach could cost far less than the V-22 including $120 million from C-2 and E-2D commonality. In February 2015, the Navy's FY 2016 budget confirmed the V-22's selection for the COD mission, which shall eventually replace the C-2 in the U.S. Navy.