KC-10 Extender

Overview:

The KC-10 Extender is an air-to-air tanker aircraft in service with the United States Air Force derived from the civilian DC-10-30 airliner. The KC-10 was the second consecutive McDonnell Douglas transport aircraft to be selected by the US Air Force following the C-9 Nightingale. Beginning with the Vietnam War doubts began to be raised about the ability of the 700+ strong KC-135 fleet to meet the needs of the United States’ global commitments. The air-refueling fleet was deployed to South-East Asia in support of tactical aircraft and strategic bombers, while maintaining the US-based support of the nuclear bomber fleet. As a result, studies began into the feasibility of acquiring an air-to-air tanker with a greater capability than the KC-135 fleet, but did not progress well due to lack of funding. The 1973 Yom Kippur War and the US Operation Nickel Grass demonstrated the necessity of adequate air-refueling capabilities. Denied landing rights in Europe, USAF C-5 Galaxies were forced to carry a fraction of their maximum payload on direct flights from the continental United States to Israel. As a result C-5 crews were soon trained in aerial-refueling and the Department of Defense concluded that a more advanced tanker was needed. In 1975, under the "Advance Tanker Cargo Aircraft" program, four aircraft were evaluated: the C-5 itself, the Boeing 747, the McDonnell Douglas DC-10, and the Lockheed L-1011. The U.S Air Force selected McDonnell Douglas's DC-10 over Boeing's 747 in December 1977. The design for the KC-10 involved only modifications from the DC-10-30CF design. The major changes were the addition of a boom control station in the rear of the fuselage and extra fuel tanks below the main deck. The KC-10 has both a centerline refueling boom and a drogue/hose system on the right side of the rear fuselage. Other changes from the DC-10-30CF include the removal of most cargo doors and windows. The KC-10 first flew on 12 July 1980. Early aircraft featured a paint scheme with light gray on the airplane's belly and white on the upper portion. A gray-green camouflage scheme was used on later tankers. Aircraft have since been switched to a medium gray color. The KC-10 boom operator is located in the rear of the airplane with wide window for monitoring refueling. The operator controls refueling operations through a digital, fly-by wire system. A total of 20 KC-10s were later modified to add wing-mounted pods for added refueling locations. In addition to the USAF refueling boom, the KC-10's hose and drogue system allows refueling of U.S. Navy, Marine Corps, and most NATO allied aircraft. This gives the KC-10 the ability to refuel USAF, USN, USMC and other NATO aircraft, all in the same mission. A need for new transport aircraft for the Royal Netherlands Air Force was first identified in 1984. In 1991 four categories of transport requirements were established. Category A required a large cargo aircraft with a range of at least 4500 km and the capability to refuel F-16s. In 1992, 2 DC-10-30CFs were acquired from Martinair in a buy/leaseback contract. When one of the bought aircraft was lost in the Martinair Flight 495 crash, a third aircraft was bought from Martinair. The conversion was handled via the United States foreign military sales program, which in turn contracted McDonnell Douglas, the designer of both the DC-10 and the KC-10 tanker. Costs for the conversion were initially estimated at $89.5 million (FY 1994). The aircraft was to be equipped with both a boom and a probe and drogue system. However, because McDonnell Douglas did not have any experience with the requested Remote Aerial Refueling Operator (RARO) system, and because the third aircraft differed from the original two, the program could not be completed at budget. By omitting the probe and drogue system and a fixed partition wall between the cargo and passenger, the cost could be limited at $96 million. To make up for the cost increase McDonnell Douglas hired Dutch companies to do part of the work. The actual converting of the aircraft for instance was done by KLM. Conversion of the aircraft was done from October 1994 to September 1995 for the first aircraft and from February to December 1995 for the second. This was much longer than planned, mostly because McDonnell Douglas did not deliver the parts in time. This would have again increased the cost, but in the contract for the AH-64 Apaches which the Royal Netherlands Air Force also bought from McDonnell Douglas, the price was agreed to be kept at $96 million.

Specifications:

Role

• Air-to-air tanker.

Introduced

• 1981

Status

• Active service.

Primary Users

• United States Air Force.
• Royal Netherlands Air Force (KDC-10).

Produced

• KC-10: 1979-1987

Number Built

• KC-10: 60
• KDC-10: 4

Unit Cost

• KC-10: US$88.4 million (1998).

Crew

• 1 pilot, 1 co-pilot, 1 flight engineer, 1 boom operator.
• Total: 4

Length

• 181 ft 7 in (54.4 m).

Height

• 58 ft 1 in (17.4 m).

Empty Weight

• 241,027 lb (109,328 kg).

Loaded Weight

• 593,000 lb (269,000 kg).

Max Takeoff Weight

• 590,000 lb (267,600 kg).

Powerplant

• 3× F103/General Electric CF6-50C2 turbofans.
• 52,500 lbf (236 kN) each.

Maximum Fuel Capacity

• 356,000 lb (160,200 kg) (limited on takeoff by MTOW).