There are three distinct versions of the E-2C Aircraft. Each version is identified by its installed radar configuration. Omnibus II aircraft Group 0 has the AN/APS-138 radar installed. Omnibus II Update Development Program (UDP) Group I has the AN/APS-139 radar installed and reached Initial Operating Capabilities (IOC) in December 1988 with delivery of aircraft A-125. Omnibus II UDP Group II Aircraft have the AN/APS-145 radar installed and reached IOC in April 1992 with delivery of aircraft A-145. The latest version of the E-2C Aircraft is the "Hawkeye 2000," Group II (M), with fleet introduction in FY02.
Improvements to the E-2C Aircraft resulted in physical changes affecting many areas of the aircraft; i.e., a redesigned nose cap and boat tail, a rotodome that does not have the capability of being raised or lowered except for maintenance functions, internal equipment relocation and rewiring, a new state-of-the-art radar, and a new engine with improved engine power and reduced specific fuel consumption.
The current model operating in the Fleet, the E-2C is equipped with radar capable of detecting targets anywhere within a three-million-cubic-mile surveillance envelope while simultaneously monitoring maritime traffic. Each E-2C also can maintain all-weather patrols, track, automatically and simultaneously, more than 600 targets, and control more than 40 airborne intercepts.
Built during the early 1970s, the "Group 0" E-2C was powered by two T56-A-425 turboprop engines and utilized an AN/APS-120 radar. The two Allison T-56-A-425 turboprop engines use constant speed Hamilton-Standard propellers. Each engine develops a maximum of 4,600 Indicated Horsepower (IHP) at takeoff. Called "The Eyes of the Fleet," it was the world's premier AEW platform; it became a model for Air Force AWACS development and evoked interest from many foreign allies. In 1978 the AN/APS-125 Advanced Radar Processing System was introduced with automatic overland detection and tracking capability. In 1984 it was succeeded by the AN/APS-138, now referred to as Group 0 configuration, with improved operation in an Electro-Magnetic Interference (EMI) environment.
In 1988, the Group I version was introduced featuring an upgraded T56-A-427 engine, which eliminated operating restrictions imposed by growth in the aircraft's gross weight due to incorporation of new systems. The T56-A-427 engines have carried the E-2C to twenty altitude and time-to-climb world records in the medium turboprop aircraft category. These engines have extended the Hawkeye's on-station time and provide greater range. The new engine provides much improved single-engine rate of climb; 23% more horsepower at high ambient temperatures; 13% lower specific fuel consumption which increases both the range and the time on station; 12% higher service ceiling at 37,000 feet and 6% higher cruising speed at 260 knots. In addition, Group I provided antijam antennas, boosted the avionics cooling capacity 20%, and provided cross-bleed engine starting, new engine instruments and improved cockpit lighting. The radar was updated to the AN/APS-139 with a High-Speed Processor that doubled the track files maintained by the system. Eighteen of these aircraft were built, and later upgraded to the Group II configuration.
The Group II upgrade represents the biggest advance in AEW technology in two decades. The "Group II" began entering the U.S. Fleet in the early 1990s and was scheduled to replace all remaining "Group 0" aircraft before the year 2010. The "Group II" is powered by two T-56-A-427 turboprop engines with a maximum of 5,100 IHP at takeoff. The Group II AN/APS-145 radar system provides fully automatic overland targeting and tracking capability, an improved IFF system, and a 40 percent increase in radar and IFF ranges. The E-2C Group II features extended radar range, Improved overland detection capability, Color displays and JTIDS, GPS and voice satellite communications. Its AN/APS-145 radar alleviates saturation, tracking overload, and overland tracking clutter. Group II increases radar volume by 96%; target track capability by 200%; number of targets displayed by 1000%; and target recognition capability through the use of color displays.
- AN/APS-145 Radar - Provides fully automatic overland detection and tracking, and significantly extends the radar detection limits with a range in excess of 300 miles. Advantages include reduced operator workload, effective elimination of blind speeds and an extremely stable surface plot.
- Improved Identification Friend or Foe (IFF) - Extends IFF range to radar limits, enables multi-mode simultaneous operation and incorporates an auto jam strobe to alert operators to jamming in the IFF band.
- Enhanced High Speed Processor - To handle the increased radar track file and required expansion of display symbol capacity, a high-speed parallel processor is incorporated into the mission computer which expands the active track file by 400% over Group 0. The enhanced high-speed processor equipped L-304 computer allows the E-2C the capability to process more than 2000 tracks.
- Enhanced Main Display Units - Enhanced tactical displays provide each operator with an improved visual representation of the total tactical picture through expansion of symbology display capacity by 1000%, multicolor display, map overlays of geographic features, zoom capability, and auxiliary data display windows.
- Joint Tactical Information Distribution System (JTIDS) - Incorporates several anti-jam features to allow uninterrupted voice and data communications, also enhancing interoperability with platforms such as the USAF AWACS and F-15. Equipped with the Joint Tactical Information Distribution System (JTIDS), the E-2C Group II is the cornerstone for fleet and joint service employment.
- Global Positioning System (GPS)- The Carrier Aircraft Inertial Navigation System (CAINS II) is augmented by GPS to enhance navigation and data link reference accuracy, which are key to tactical operations. The E-2C Group II is the first carrier-based fleet aircraft configured with the Global Positioning System (GPS), which allows the aircraft to use satellite networks to instantaneously calculate aircraft position to within a few meters. This system greatly enhances the E-2C Group II's navigation and data link accuracy.
In December 1991, deliveries began on the Group II version. Northrop Grumman restarted its Hawkeye production line in St. Augustine, Fla., in 1994, after the Navy ordered the first four of an expected 36 new Group II E-2C's.
During the late 1980s and early 1990s the E-2C Hawkeye has supported numerous naval engagements, including the 1985 intercept of the aircraft containing the hijackers of the liner Achille Lauro; the strikes against Libya in 1986; and the Persian Gulf War.Carrier-based E-2C Hawkeye airborne early warning aircraft directed F-14 Tomcat fighters that provided combat air patrol during the two-carrier battle group joint strike against terrorist-related Libyan targets in 1986, and during the crisis period preceeding and following the strike. E-2Cs and AEGIS cruisers, working together, provided total air mass superiority over the American fleet. During this time, American aircraft made 153 intercepts of Libyan air force attempts to overfly the U.S. fleet, intercept the U.S. fighter combat air patrol, or gather intelligence information. Not once did a Libyan aircraft get into firing position before it was locked into the sights of a U.S. aircraft or AEGIS platform missile. E-2 aircraft also have worked extremely effectively with U.S. law enforcement agencies in drug interdiction operations.
|Group 0||Group I||Group II (X)||Group II (N)||Group II (M)||Group II (C)|
|AN/APS-138 Radar System||AN/APS-139 Radar System||* AN/APS-145 Radar System|
|APX-72 IFF System||* APX-100 New IFF System|
|ALR-73 PDS System||* ALQ-217 ESM System|
|L-304 Computer||L-304 Computer & Enhanced High Speed Processor||* MCU Computer|
|Displays MDU||Displays Monochrome||* New Tactical Displays (EMDU/ MFCDU)||* New Tactical Displays (ACIS) 3 MFCDUs|
|2 HF/3 UHF Radios|
|3 VHF/UHF Have Quick Radios|
|* ARC-210 Radio|
|* Joint Tactical Information Distribution System|
|* Link-4A, 11, 16 Data|
|* Global Positioning System|
|Sat Comm Mini DAMA (AEC)||* Sat Comm Forward Equipment Compartment (FEC)|
|ASN-92/50 Navigation Suite||* ASN-139 Navigation Suite (2 Sets)|
|ASW-15 AFCS System||* ASW-50 SAFCS System|
|10-Ton Cooling System||12-Ton Cooling System||* 15-Ton Cooling System|
|T56-A-425 Engines||T56-A-427 Engines|
The E-2C+ Hawkeye is modified with the eight-bladed NP2000 propeller. The new propeller, made by Hamilton-Sundstrand, increases performance and safety along with better maintenance techniques. The Navy is slowly phasing in the 8 blade props on the E-2Cs.
The new propeller is quieter, with less vibration on the airframe and equipment. It provides a little more SHP. It is virtually impossible to pitchlock, since the 8 blades can feather with loss of hydrolic oil pressure. One of the interesting performance attributes of the new prop is the reduced noise inside the airplane. The pilots and crew are able to hear noises they have never heard before. But the problem is, they don't know if these noises have always been there and they were unable to hear them because of the noise of the old props, or if the new noises are related to the new props.
On April 19, 2001, at Naval Air Station Patuxent River, Md., the U.S. Navy successfully conducted the first flight of an E-2C equipped with state-of-the-art composite eight-bladed propellers. The Hamilton Sundstrand NP2000 is a digitally controlled, all-composite propeller blade system that will replace the electro-mechanical, steel spar propellers that are on all Hawkeyes, both in production and in service, and all Northrop Grumman C-2A Greyhound carrier-on-board delivery aircraft. Easier and less expensive to maintain than the current four-bladed propellers, improves performance throughout the flight envelope and reduces noise.
Because the E-2C will serve the Navy well into the twenty-first century, continual modifications and upgrades have kept the aircraft ahead of the threat. The production E-2C, known as Hawkeye 2000, improves the Hawkeye's capabilities in detection, processing, identification, communications and navigation. Key among the advances is the mission computer upgrade (MCU) with its advanced control indicator set workstations. MCU is a smaller, lighter, more powerful mission computer that allows even more capabilities such as the Cooperative Engagement Capability (CEC) upgrade. CEC will enable the Hawkeye to serve as the fleet's information hub, fusing and distributing information from sources such as satellite and shipborne radar. The mission computer upgrade test aircraft flew for the first time in early 1997, and was sent to the Patuxent River, Md., Naval Air Test Center for testing. Low-rate initial production of the new mission computer was declared in July 1997.
The first test Hawkeye 2000 successfully completed its first flight in 1998 and operational evaluation by the U.S. Navy in March 2001. Production of the Hawkeye 2000 began in 1999 under a five-year $1.3 billion multiyear (MYP) contract. Northrop Grumman is producing 21 of the next-generation aircraft for the Navy, and three more for international customers. France is the buyer for one of the Hawkeyes, though that aircraft will be in Group II configuration to match the other two French Hawkeyes now in service. Taiwan has received two Hawkeyes under this order. The U.S. Navy took delivery of the first production Hawkeye 2000 in October 2001.
Beyond new production, Japan and Egypt initiated programs to upgrade their fleets to a Hawkeye 2000 export configuration, which does not contain the CEC and satellite communications. Egypt also has procured another U.S. Navy Hawkeye and Northrop Grumman upgraded it to the new configuration. This will give Egypt a fleet of six Hawkeyes.
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