Military


C-22

The C-22B, a Boeing 727-100, is the primary medium-range aircraft used by the Air National Guard and National Guard Bureau to airlift personnel. The C-22B's unique arrangement of leading-edge devices and trailing-edge flaps permit lower approach speeds, thus allowing operation from runways never intended for a 600-mph (Mach 0.82) aircraft.

By the late 1990s there were three C-22B's in use, all assigned to the 201st Airlift Squadron, District of Columbia Air National Guard. In March 2000 it was announced that the 201st Airlift Squadron would retire the C-22B aircraft with no loss of manpower.

The aircraft has heated and pressurized baggage compartments - one on the right side forward and the second just aft of the wheel well. The two compartments provide 425 cubic feet (12.75 cubic meters) of cargo space. The fuselage also incorporates a forward entry door and hydraulically opened integral aft stairs in the tail cone.

The flight controls consist of a hydraulically powered dual-elevator control system with control tab to assist during manual operation. Hydraulically powered rudders use two main systems with a standby system for the lower rudder. The ailerons also are powered by dual-hydraulic systems. They have balance tabs on the outboard and control tabs on the inboard, which assures adequate maneuverability in the event of a total hydraulic failure. The flight spoiler systems assist ailerons and also function as speed brakes. The aircraft's tricycle landing gear consists of a dual-wheel nose gear, left and right dual-wheel main gear, and a retractable tail skid which prevents damaging the aircraft in case of overrotation. Nose wheel steering is hydraulically powered and controlled by a steering wheel to approximately 78 degrees in either direction. Fuel is contained in three main tanks inside the wing center section. Rapid pressure fueling and defueling is accomplished at the fueling station on the right wing. The total fuel capacity is approximately 50,000 pounds (22,500 kilograms) of JP-4. Fuel may be dumped down to 35,000 pounds (15,750 kilograms) from all tanks.

The C-22B requires four crew members and three or four in-flight passenger specialists for passenger service and safety. The avionics package includes one UHF and two VHF radio altimeters, variable instrument switching and two Collins FD-108 flight directors. A third vertical gyro and an additional VHF transceiver are available in case of failure of the primary systems.

The C-22B was introduced by the airline industry in 1963. It proved to be a major innovative design with its three Pratt & Whitney JT8D turbofan engines, one on each side of the rear fuselage and the third in the tail cone. Currently, there are three C-22B's in use, all assigned to the 201st Airlift Squadron, District of Columbia Air National Guard.

The C-22Bs are modified Boeing 727-100 series aircraft, out of production since 1969. Spare parts are increasingly costly and difficult to obtain as commercial operators phase out this series of Boeing 727 and supply sources dwindle. The current fleet suffers from numerous operational restrictions. The aircraft are aging and have high operating, maintenance, and support costs. Communication and navigation systems are old and fail to meet the new requirements for air traffic management and separation mandated by Reduced Vertical Separation Minimums (RVSM) and Global Air Traffic Management (GATM) requirements. The C-22B fleet fails to meet either FAA or International Civil Aviation Organization (ICAO) Stage 3 noise and air pollution requirements. The Pratt & Whitney (P&W) JT-8 engines, which power the C-22B, are out of production and no new spare parts are being manufactured. The engines are expensive to operate, and emit more pollutants than newer, more fuel-efficient engines. The aircraft are heavily dependent upon ground support equipment, and were the only C-22Bs flying in the USAF.

The C-22 Replacement Program calls for a most probable quantity of four (one initial plus three options) FAA certified commercial intercontinental passenger aircraft reconfigurable to accommodate a minimum of 40 passengers and 7 crew (low volume, office environment with DV area) or a minimum 70 passengers and 5 crew (high volume passenger transport). The ability to reconfigure the interior for medical evacuation by installing 1 to 7 Spectrum 500 beds is also required. The aircraft shall be capable of dispatch on short notice to any suitable airfield in the world from operating locations at Andrews AFB, Maryland and shall be capable of non-stop flight from Andrews AFB, Maryland to Moscow, Russia and from Frankfurt, Germany to Andrews AFB, Maryland with 7 crew and 40 passengers. Worldwide clear and secure voice, facsimile, and data communications are required to support the passengers.

The C-22 is programmed to begin leaving the ANG's aircraft inventory in FY 2001, culminating in FY 2003. A suitable replacement program has not yet been implemented to assume the special mission responsibilities currently assigned to the C-22.

By any standard, the three-engine Boeing 727 must be considered the most successful jet transport aircraft yet produced. The prototype first flew in 1963, and the type was introduced into service by Eastern Airlines in early 1964. Total orders to mid-1982 numbered 1825, with [428] the aircraft being produced at the rate of 2 per month. The 727 is operated all over the world by some 85 airlines; It is rarely possible to - visit a domestic airport served by a scheduled airline without seeing a Boeing 727 during the course of a day. The 727 is popular with the airlines primarily because it can be operated profitably over range segmerits of various lengths and passenger-load requirements, and its relatively short field capability permits operation from a large number of airports too small to accommodate 707 class aircraft. Many studies were made over the years in an effort to find a replacement for the ubiquitous Douglas DC-3; though with different range and payload characteristics, and with different field length and cruising speed capabilities, the 727 may be considered as the modern-day counterpart of the DC-3 that first appeared in 1935.

The aircraft was first produced as the 727-100, and a later stretched version designated the 727-200 was introduced. Of the 1825 aircraft so far ordered, over 1300 have been for the 727-200, which is the only version now in production. The aircraft is produced in both passenger and convertible cargo-passenger configurations.

The choice of three engines for the 727 was dictated by a compromise between cost and airport performance. For operation on hot days from airports located at high altitudes, the three-engine arrangement offered significantly better takeoff and climb performance with engine out than was practical for an efficient twin-engine design, but at a great deal lower cost than for a four-engine aircraft.

The 727-200 is a low-wing design; according to the data given in table VII, the wing planform geometry is similar to that of the 707. The engine arrangement results in a horizontal tail mounted at the tip of the vertical fin in a T-tail configuration. The lateral and longitudinal control surfaces are of the same type as those employed on the 707. In contrast to the 707, however, all the controls on the 727 are hydraulically actuated. In order to allow operation from airports of medium size, the 727 is equipped with very powerful high-lift devices. The trailing edge of the wing has triple-slotted flaps. The leading edge has a slat on the outboard two-thirds of the span and Krueger flaps on the inboard portion of the wing. With these high-lift devices, a stalling speed of 121 miles per hour is obtained at the maximum landing weight of 160 000 pounds. The main landing gear employs two-wheel bogies instead of the four-wheel type used on the 707. The gear retracts inward into the wing at the root. The large negative deflection of the horizontal tail and the flame trailing from the tail skid as it drags along the runway.

The Boeing 727-200 has a gross weight of 210 000 pounds and in full tourist configuration can accommodate 189 passengers in a 6-abreast arrangement. The upper fuselage diameter of the aircraft is the same as that of the 707 and the shorter range Boeing 737. Thus, to the passenger, all three aircraft appear to have the same cabin size except for length. The 727-200 is capable of a maximum range of 3738 miles with full fuel tanks; with maximum payload, it has a range of 3335 miles. The cruising speeds of the aircraft are comparable to those of the 707 and the DC-8.



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