The Boeing 767 is an Airborne Warning and Control System (AWACS) aircraft. It was designed in response to the Japan Air Self-Defense Force's requirements, and is essentially the Boeing E-3 Sentry's surveillance radar and air control system installed on a Boeing 767-200. The Boeing 767 AWACS airborne warning and control system has been selected by Japan to carry out airborne surveillance and command and control (C2) operations for tactical and air defence forces.
The surveillance system is based on a flexible, multimode radar, which enables AWACS to separate maritime and airborne targets from ground and sea clutter radar returns.
Production of the 707 airframe, which has been used since 1977 for the Boeing E3 AWACS, ended in May 1991. Following studies of the most suitable follow-on aircraft for the AWACS mission, Boeing announced in December 1991 that it would offer a modified Boeing 767 jet as the platform for the system.
The aircraft is flown by two pilots rather than four aircrew as on the E3 AWACS. There are 18 AWACS mission crew led by a mission director and a tactical director.
Development
On September 6, 1976, Soviet Air Force pilot Viktor Belenko successfully defected to the West, flying his MiG-25 'Foxbat' to Hakodate, Japan. During this incident, Japan Self-Defense Force radar lost track of the aircraft when Belenko flew his MiG-25 at a low altitude, prompting the Japan Air Self-Defense Force (JASDF) to consider procurement of airborne early warning aircraft.
In 1976, the U.S. Air Force was about to deploy the E-3 Sentry airborne warning and control system aircraft, which was considered to be the prime candidate for the airborne early warning mission by JASDF. However, the Japan Defense Agency (JDA, now Ministry of Defense) realized that the E-3 would not be readily available due to USAF needs and instead opted to procure the American E-2 Hawkeye AWACS aircraft. The E-2C was put into service with the Airborne Early Warning Group (AEWG) at JASDF Misawa Air Base in January 1987.
In 1991, the JDA requested funds to upgrade the airborne early warning system by procuring the E-3. Unfortunately, production of the Boeing 707-based E-3 airframe had ended in 1991 and the plan was shelved. The following year, Boeing proposed a 767-based AWACS, and the JDA agreed to procure two E-767 in fiscal year 1993 and two more in fiscal year 1994.
Aircraft No 1 and No 2 were delivered to the company's first customer, the Government of Japan, in March 1998. The final two aircraft were delivered in January 1999. All four aircraft entered service with the Japanese Air Self-Defense Force (JASDF) in May 2000. Boeing delivered the 50th 767 jetliner to Japan Airlines in July 2009. The Boeing 767 is being operated in more than 130 countries worldwide.
Design
The base airframe for 767 is that of a 767-200ER, Boeing designation 767-27C. (The "7C" designation is the Boeing customer code for the JASDF). The 767 airframe offers about 50 percent more floor space and nearly twice the volume of the 707 on which the E-3 is based. The mission electronics equipment are installed in forward cabin to balance the weight with the rotodome mounted above the aft fuselage. The aft cabin contains the crew's rest area, galley, and lavatory. The basic 767 airplane is manufactured by Boeing Commercial Airplane Group in Everett, Washington, and then flown to Boeing Information, Space & Defense Systems facilities in Wichita, Kansas, where the airframe is modified to accommodate the prime mission equipment. All aircraft are returned to the Boeing Seattle facility, where mission equipment and the rotodome are installed.
Major subcontractors include Northrop Grumman, General Electric, Rockwell Collins and Telephonics, which have been involved in the previous Boeing AWACS programs.
AWACS radar
The antenna systems for primary radar and the information friend or foe (IFF) interrogator are mounted in a 9.1m diameter circular radome above the aircraft fuselage. The primary radar is the AN/APY-2 Passive electronically scanned array radar system, developed for E3 AWACS by Northrop Grumman in Baltimore. This system is a three-dimensional radar that measures azimuth, range, and elevation simultaneously, and has superior surveillance capability over water compared to the AN/APY-1 system on the earlier E-3 models. The AN/APY-2 is a Pulse-Doppler radar that can determine the velocity of a tracked target. This surveillance system includes a flexible, multi-mode radar, which enables AWACS to separate maritime and airborne targets from ground and sea clutter returns that limit other modern radar systems. The radar operates at about 10GHz (wavelength about 10cm) in the E/F bands. It scans mechanically in azimuth at six revolutions per minute, and electronically in elevation. AN/APY-2's antenna and Identification Friend or Foe (IFF) Mk XII system's antenna are housed in the rotodome back to back. In flight, when the radar is not operational, the slip rings and bearings are kept lubricated by rotating the radome at one cycle every four minutes.
The main modes of operation of the radar are: pulse Doppler non-elevation scan; pulse Doppler elevation scan; beyond-the-horizon mode; maritime mode for detection of surface ships; combined operational modes using data interleaving for long-range detection; and passive mode operation in which the transmitters are switched off for radar-silent operations.
The AWACS radar provides a 360° view of the area. At operating altitudes it can detect targets more than 320km away. Targets are separated and individually managed and displayed on situational displays.
In May 2006, Japan requested the foreign military sale of four radar system improvement programme (RSIP) kits, as fitted on USAF, UK and Nato E-3 AWACS.
Northrop Grumman was awarded the contract for the upgrade in December 2006. The RSIP upgrades the capability against threats from small radar cross section targets, cruise missiles and electronic countermeasures.
The improvement in sensitivity against small and stealthy targets is achieved through a new surveillance radar computer to replace the digital Doppler processor and radar correlator, and the translation of the associated software into ADA language.
The main AWACS operations cabin behind the flight deck is laid out in equipment bays for communications, data and signal processing, navigation, and identification equipment. The AWACS officers and operator stations are equipped with Hazeltine command and control consoles fitted with high-resolution colour displays. The main signal and data processing computer, Lockheed Martin CC-2E, has a main storage capacity of over three million words; five times larger than that of the CC-2 computers installed on the E3 AWACS aircraft.
The AWACS mission equipment on the 767 AWACS takes advantage of the combat-proven avionics currently employed on-board operational AWACS aircraft, and is interoperable with the AWACS aircraft currently in service.
The aircraft's navigation system is based on two LN-100G inertial navigation systems with integrated satellite global positioning systems, supplied by Northrop Grumman (formerly Litton).
Turbofan engines
The 767 aircraft is powered by two General Electric CF6-80C2B6FA turbofan engines, providing 61,500lb thrust. The more powerful engines on the 767 AWACS compared to the 707/E3 AWACS allow the aircraft to carry a heavier payload, have a greater range and to fly higher. The original 90 kVA electrical generator in each engine was replaced with 150 kVA generators to provide electric power to the radar and other equipment.
Performance
The 767 AWACS aircraft can fly at a maximum speed of 800km/h. The range and service ceiling of the aircraft are 10,370km and 12,222m respectively. The endurance of the aircraft is 13 hours at 300nm radius. The aircraft weighs 85,595kg, while the maximum take-off weight is 175,000kg.
Specifications
General characteristics
Crew: Flight:2 Mission:8-10
Length: 159 ft 2 in (48.5 m)
Wingspan: 156 ft 1 in (47.6 m)
Height: 52 ft (15.8 m)
Empty weight: 188,705 lb (85,595 kg)
Loaded weight: 284,110 lb (128,870 kg)
Max. takeoff weight: 385,000 lb (175,000 kg)
Powerplant: 2 × General Electric CF6-80C2B6FA turbofan, 61,500 lbf (282 kN) each
Performance
Maximum speed: Mach 0.86
Cruise speed: Mach 0.80 (530 mph, 851 km/h)
Range: 5,600 nmi (10,370 km)
Service ceiling: 40,100 ft (12,200 m)
Endurance: 9.25 hours on station at 1,000 nautical-mile radius;
13 hours at 300-nautical mile radius (no aerial refueling capability).
Avionics
Northrop Grumman AN/APY-2 Doppler radar