TYPE: Airborne early warning and control system.

PROGRAMME: First flight of first of three prototypes 21 October 1960; total 59 production E-2As, of which 51 updated to E-2B by end 1971 apart from two TE-2A trainers and two converted to E-2C prototypes; first flight of E-2C prototype 20 January 1971; production started mid-1971, first flight production aircraft 23 September 1972; 219 of all E-2C versions ordered, of which 211 had been delivered by the first quarter of 2006. Flying hours by that time exceeded one million.

CURRENT VERSIONS: E-2C: Current service and production version (as detailed). Baseline aircraft (65 built) had AN/APS-120 or AN/APS-125 radar; replaced in production by 'Group 0' version (35 built) with AN/APS-138 radar. In closing stages of 2004, US Navy possessed only four active 'Group 0' aircraft; assigned to VAW-77 at Atlanta, Georgia, these have since been retired from service.
AN/APS-139 and Allison T56-A-427 engines formed Group I update; first operational aircraft (163538) delivered to VAW-112 on 8 August 1989; 18 built; AN/APS-139 could detect cruise missiles at ranges exceeding 100 n miles (185 km; 115 miles); also monitored maritime traffic; radar coverage extended by AN/ALR-73 passive detection system (PDS), detecting electronic emitters at twice radar detection range. All Group I aircraft subsequently modified to either TE-2C or Group II standard. AN/APS-145 in Group II aircraft from December 1991; other enhancements give Group II 96 per cent expansion in radar volume, 400 per cent extra target tracking capability, 40 per cent more radar and identification range and 960 per cent increase in numbers of targets displayed. Group II added JTIDS in 1993-94; also has GPS. Final Group II aircraft for US Navy delivered in mid-2001; one since modified to TE-2C configuration. Retrofit with eight-blade propellers was due to start in 2001, with first operational example expected in fourth quarter; however, vibration problems encountered in testing caused delay and new propeller did not enter service until mid-2004. On 15 August 2005, Northrop Grumman announced completion of Group II Mission Computer Replacement Program (MCRP), whereby approximately 48 aircraft were upgraded; this involved installation of new processor and open systems, Commercial Off-The-Shelf (COTS) hardware. Benefits include predicted MTBF in excess of 8,000 hours for mission computer; reduced hardware weight from 318 kg (700 lb) to 48 kg (105 lb); lowered heat dissipation from 1,700 W to 80 W; and reduced central processing unit load time to below 30 seconds (previously in excess of 2.5 minutes).
TE-2C: Training model, based on E-2C; two conversions (158639, 158648) originally undertaken, of which one (158639) was later assigned to JTIDS development with Northrop Grumman. At least four further conversions (159105, 163029, 163848, 164110) subsequently made for training purposes with VAW-120 at Norfolk, Virginia, of which only the last mentioned was in service in October 2005. Five new-build examples to be acquired in FY04—07, with these lacking radar, but including wiring and hardware systems to facilitate future conversion.
E-2T: Originally reported to be conversion of E-2B for Taiwan, but new-build aircraft equivalent to E-2C Group I actually supplied; AN/APS-138 radar and electronic warfare upgrades. Delivery began in 1995, with further two obtained following agreement in July 1999; these to Hawkeye 2000E standard, with AN/APS-145 radar, but lacking CEC and satcom equipment. Delivery of first accomplished in USA 10 August 2004, with second following by end of year; both subsequently shipped to Taiwan, arriving there 19 May 2005. Original four aircraft being upgraded to Hawkeye 2000E standard during 2006-07. Alternative, unofficial, designation of latest Taiwanese aircraft is E-2K, derived from Hawkeye 2000 (E-2C 2K).
Hawkeye 2000: In December 1994, company received US$155 million contract to redefine E-2C as the Hawkeye 2000. Key element is mission computer upgrade (MCU), with new equipment based on Raytheon’s Model 940.
Initial trials of upgraded mission computer installed on second Group II aircraft (164109) began with first flight on 24 January 1997 and were completed in July 1997, at which time authorisation given for low-rate initial production of new mission computer. However, early flight trials revealed software problems that delayed production of new mission computer by about a year. More ambitious technical and operational evaluations undertaken with five modified aircraft in 1999-2001. All were Group II aircraft fitted with MCU and ACIS (see below) elements of proposed Hawkeye 2000; first two delivered to Patuxent River for initial evaluation by May 1999. At least four to Point Mugu from August 1999, joining VAW-117 for operational evaluation from October, with latter phase including deployed duty aboard a carrier for full battlegroup operations. In meantime, another E-2C (163849) used as testbed for satcom, vapour-cycle cooling upgrade and Navy’s USG-3 co-operative engagement capability (CEC) package, following first flight in April 1998; latter results in addition of 1.37 m (4 ft 6 in) antenna dish under belly containing omnidirectional transceiver that connects with command centres on parent aircraft carrier and surface combatant warships; provision of satcom evident through addition of cone-shaped fairing on top of rotodome.
New mission computer is less than half the weight of L-304, one-third of volume, and offers 15 times the processing power; other improvements for Hawkeye 2000 include government-furnished advanced control indicator set (ACIS), satellite-based voice and data communications capability, a new Honeywell vapour-cycle cooling system, air-to-air refuelling capability (if required) and inclusion of equipment and systems that form part of Navy CEC package. MCU and ACIS make use of commercial off-the-shelf technology incorporating open architecture.
In April 1999, contract awarded for 24 aircraft for US Navy (21 Hawkeye 2000s) as five-year procurement package, Taiwan (two Hawkeye 2000Es) and France (one Group II Hawkeye); in early 2003, US Navy announced intention to award second multiyear procurement contract, for total of eight aircraft to be acquired at rate of two per year during FY04 to FY07, with first delivery programmed for January 2007. Five will be configured as TE-2C trainers, lacking mission system. First deployment of Hawkeye 2000 with US Navy by VAW-117 squadron in 2003. Export-configured Hawkeye 2000s lack CEC and satcom facilities.
E-2D: Originally known as Advanced Hawkeye, with E-2D designation formally assigned in July 2004, but not officially announced until March 2005. Full-scale development began in early August 2003, following award of system development and demonstration (SDD) contract to Northrop Grumman. Total of USD1.9 billion to be invested in new version by 2012, of which USD413.5 million will go towards developing new space-time adaptive UHF radar; Lockheed Martin Naval Electronics and Surveillance Systems is prime contractor for radar, with Northrop Grumman Electronic Systems furnishing multiple solid-state transmitters and Raytheon providing receivers. The new radar, designated AN/APY-9 by 2006, will feature an L-3 Communications Randtron Antenna Systems UHF electronically scanned ADS-18S array in the existing rotodome and is expected to have twice the range of the current AN/APS-145 radar, as well as superior performance in eliminating clutter and ability to track small targets like cruise missiles. BAE Systems responsible for IFF system. Critical design review (CDR) of new radar undertaken in early 2005 and was reported to be 'very successful'; overall aircraft CDR completed in November 2005.
Other features include surveillance infra-red search and track (SIRST) system, modular communications equipment, multisensor integration and tactical ('glass') cockpit featuring three flat-panel displays, with latter enabling co-pilot to augment mission system operators by performing some tactical functions. Airframe structure strengthened and lightened through application of improved manufacturing techniques, but without recourse to composites. US Navy is prime customer, but another potential buyer is UK Royal Navy, which has emerging requirement for new AEW platform to operate from future aircraft carrier. US planning calls for E-2D to augment traditional AEW roles with increasing emphasis on battle management, land-sea-air connectivity, surveillance, electronic support measures, SAR, emergency air traffic control and border and EEZ patrol.
Communication suite to be greatly expanded and include additional satellite communication systems, plus multiple AN/ARC-210 radios with MIDS tactical datalink and Block 2 CEC sensor datalink. E-2D also planned to be first US Navy aircraft to have Joint Tactical Radio System (replacing AN/ARC-210 units). Upgraded IFF to be produced by BAE Systems.
Power plant will be T56-A-427A version of existing Hawkeye engine, with digital electronic engine control and eight-blade Hamilton Sundstrand NP2000 propellers from outset. MTOW will exceed 25,850 kg (57,000 lb) with maximum landing weight increased to about 20,412 kg (45,000 lb). Hamilton Sundstrand also to provide new 255 kVA generator. Following tanker proximity trials, installation judged possible of refuelling probe above cockpit and funding requested in 2006.
Northrop Grumman received USD49 million pre-systems development and demonstration contract for E-2C RMP (Radar Modernization Program) in late 2001; work done under this 12-month contract concerned definition of physical architecture of future mission system. Northrop Grumman also conducted initial flight testing of new radar’s transmitter, receiver, antenna and rotary coupler on an NC-130H Hercules.
Two E-2D prototypes will be utilised for SDD; keel of first aircraft laid May 2005. First flight of first development aircraft expected to take place in August 2007. Subsequent deployment planning anticipates starting procurement in FY09, with an initial batch of four aircraft for operational evaluation in 2011. Further batches of four aircraft are planned for FY10 and FY11, with additional 57 in later years, giving US Navy total fleet of 75, the minimum needed to sustain carrier battle group operations at projected levels. Peak production rate not expected to exceed eight aircraft per year. IOC expected in 2011, with full operational capability due between 2015 and 2017.

CUSTOMERS: US Navy orders for E-2C had totalled 139 by FY92, of which all delivered by March 1994. Further procurement authorised December 1994, when Northrop Grumman awarded USD122.5 million contract for start-up of new assembly line at St Augustine, Florida. Initial orders for seven Group II aircraft (four with FY95 funds, three with FY96 funds); first of these new aircraft (165293) was rolled out on 24 February 1997, flew on 22 March, and was delivered to VAW-120 at Norfolk, Virginia. Further contract in December 1996 to cover advance acquisition costs of four Group II aircraft with FY97 funds; four more ordered before April 1999 award of multiyear contract for 24 aircraft for US Navy (21), France (one) and Taiwan (two). Delivery of first new-build Hawkeye 2000 to US Navy accomplished in October 2001. Five Hawkeye 2000s delivered in 2002, then five in 2003 and three in 2004, with remainder following by second quarter of 2006; additional eight aircraft (three E-2C and five TE-2C) to follow, with delivery programmed to take place between January 2007 and September 2009. Current US Navy programme status in adjacent table:

¹ Two aircraft later converted to TE-2C and 16 upgraded to Group II standard
² Includes eight aircraft for procurement in FY04-07 to sustain production until E-2D becomes available; five of these to be completed as TE-2C trainers

Major retrofit programme for USN aircraft to Group II standard was planned from FY95, but 1994 defence review established new E-2Cs more economical than retrofit; however, 16 Group I E-2Cs were upgraded to Group II at St Augustine, Florida; first returned to service on 21 December 1995. First operational squadron with upgraded Group II E-2C was VAW-123 which accepted its fourth and final aircraft on 29 April 1996.
E-2C entered service with VAW-123 at NAS Norfolk, Virginia, November 1973 and went to sea on board USS Saratoga late 1974; E-2C issued to 19 other squadrons, including three of Naval Reserve; current squadrons are VAW-112, 113, 116 and 117 at Point Mugu, California; VAW-115 at Atsugi, Japan; VAW-120, 121, 123 to 126 at Norfolk, Virginia, plus VAW-77 of Reserves at Atlanta, Georgia, for anti-drug smuggling surveillance duty. VAW-120 is training unit. Miramar was base of first Group II squadron, VAW-113, June 1992. VAW-113 first operational evaluation cruise in USS Carl Vinson, 1993. New Build Group II aircraft also issued to VAW-110 (disbanded September 1994), 112, 116 and 117. Hawkeye 2000 in process of delivery to US Navy; first operational squadron was VAW-117. VAW-116 and VAW-125 both also using Hawkeye 2000 by end of 2004, when about 15 aircraft had been accepted. VAW-113 subsequently transitioned to Hawkeye 2000 in 2005.
See table for exports. Singaporean aircraft with AN/APS-138 radar; Taiwan received E-2T with AN/APS-138 radar. Follow-on Taiwan order, for two Hawkeye 2000Es, placed in 1999, with first example handed over at St Augustine, Florida, on 10 August 2004. Israeli aircraft in storage by 1994, with three sold to Mexico in 2002; these refurbished by Israel Aircraft Industries, with first aircraft (AMP-100) handed over in Israel on 21 January 2004. Following training of Mexican personnel, this and second aircraft ferried to Mexico in June 2004; third example delivered via UK in November 2004. France signed Letter of Offer and Acceptance (LOA) in June 1995 for two aircraft; first flight of first Aéronavale aircraft on 12 March 1998, with formal roll-out ceremony at St Augustine, Florida, on 28 April 1998. Both aircraft initially retained in USA for crew training, with first E-2C (actually No 2/165456) delivered to Lann-Bihoué, France, on 14 December 1998; second in April 1999. Operating unit, 4 Flottille, formed at Lann-Bihoué January 1999. French Navy given authorisation in 1998 to purchase third Group II Hawkeye, which was delivered in late 2003 and ferried to Lann-Bihoué in February 2004.
Italy a potential customer in longer term, with requirement for at least two AEW aircraft by 2007. Egypt and Singapore said to be considering acquisition of surplus US Navy aircraft in mid-2000, with former subsequently signing contract for single example as attrition replacement; this delivered in February 2003, following upgrade to Hawkeye 2000 standard.
United Arab Emirates expected to obtain five refurbished Hawkeye 2000 aircraft from surplus US Navy stocks; possibility of sale at estimated cost of USD400 million notified to Congress on 4 September 2002. Contract was expected to be signed in first quarter of 2004, but concerns over technology transfer have caused delay and deal still not finalised by March 2006, although still then under discussion, with intention of mid-2007 purchase; aircraft will probably be fitted with in-flight refuelling probe above cockpit. India reported in early 2004 to be evaluating Hawkeye; Hawkeye 2000 demonstrated at Aero India 2005 show and apparently a candidate to satisfy Indian Navy requirement for up to six AEW aircraft, plus Coast Guard need for at least two; discussions continuing in mid-2006 but no formal request made up to that time. Malaysia also said to be contemplating purchase of E-2 in early 2005.

¹ Israeli aircraft withdrawn from use in 1994; three sold to Mexico in 2002 and refurbished by IAI before delivery in 2004
² Japanese aircraft being upgraded to Hawkeye 2000 standard; first flight of first upgraded aircraft 14 July 2004
³ Taiwanese aircraft known as E-2Ts; initial four aircraft to be upgraded to Hawkeye 2000E standard in 2006-07.
⁴ Five of the original Egyptian aircraft being upgraded to Hawkeye 2000 standard; a sixth, former US Navy aircraft, was first to be upgraded and was delivered to Egypt in February 2003 (not included in table); second upgraded aircraft delivered August 2004, with remaining four to follow by April 2007

COSTS: Procurement of 21 new Hawkeye 2000s for US Navy cost USD1.47 billion; follow-on order for eight aircraft valued at USD706 million. Upgrading of 13 Japanese aircraft to Hawkeye 2000 standard expected to cost approximately USD400 million, with cost of Egyptian upgrade of six aircraft valued at USD174 million. System Development and Demonstration (SDD) of E-2D predicted to cost USD2.1 billion between 2009 and 2012.

DESIGN FEATURES: E-2C can cover naval task force in all weathers flying at 9,150 m (30,000 ft) and can detect and assess approaching aircraft at in excess of 300 n miles (556 km; 345 miles); AN/APS-145 has total radiation aperture control antenna (TRAC-A) to reduce sidelobes to offset jamming; radar sweeps 6 million cu mile envelope and simultaneously monitors surface ships; long-range, automatic target track initiation and high-speed processing enable each E-2C to track more than 2,000 targets simultaneously and automatically, and control more than 40 intercepts; Randtron Systems AN/APA-171 antenna housed in 7.32 m (24 ft) diameter radome, rotating at 5 to 6 rpm above rear fuselage; antenna arrays in rotodome provide radar sum and difference signals and IFF.
High-mounted tapered wing; moderately sweptback tailplane with pronounced dihedral; twin fins and twin auxiliary fins, all with sweptback leading-edges and at right angles to tailplane. Rotating, circular radar housing mounted on cabane above rear fuselage; Hawkeye 2000 has satcom antenna housing on top of radome. Nose-tow catapult attachment, arrester hook and tail bumper; wings fold hydraulically on skewed hinges to lie parallel to fuselage.
Wing incidence 4° at root, 1° at tip.

FLYING CONTROLS: Conventional and fully powered, with artificial feel; tailplane has 11° dihedral; four fins and three double-hinged rudders; long-span ailerons droop automatically when hydraulically operated Fowler flaps are extended; autopilot provides autostabilisation or full flight control. Empennage (including horizontal stabilisers, elevators, rudders, vertical fins and tabs) produced by Potez Aéronautique of France, following award of contract in mid-1997 for initial batch of five assemblies; first completed assembly delivered in second quarter of 1999.

STRUCTURE: Wing centre-section has three beams, ribs and machined skins; hinged leading-edge provides access to flying and engine controls. Fuselage conventional light metal. Composites used in parts of tail.

LANDING GEAR: Hydraulically retractable tricycle type. Pneumatic emergency extension. Steerable nosewheel unit retracts rearward. Mainwheels retract forward and rotate to lie flat in bottom of nacelles. Twin wheels on nose unit only. Oleo-pneumatic shock-absorbers. Mainwheel tyres size 36x11 (24 ply) tubeless, pressure 17.93 bar (260 lb/sq in) on ship, 14.48 bar (210 lb/sq in) ashore. Nosewheel tyres 20x5.5 (12/14 ply) tubeless. Hydraulic brakes. Hydraulically operated retractable tailskid. A-frame arrester hook under tail.

POWER PLANT: Two 3,803 kW (5,100 ehp) Allison T56-A-427 turboprops, driving Hamilton Sundstrand Type 54460-1 four-blade fully feathering reversible-pitch constant-speed propellers. These have foam-filled blades which have a steel spar and glass fibre shell. T56-A-427 engines provide 15 per cent improvement in efficiency, compared with -425 installed before 1989. US Navy and Northrop Grumman seeking to extend mission duration and undertook in-flight refuelling trials in late 2004, using F/A-18 Hornet as tanker; previously, only Israel had configured Hawkeye to be refuelled in flight; further trials accomplished by test squadron VX-20 in December 2005 and January 2006, using E-2C 165294, which fitted with test probe above cockpit. December 2005 trial involved total of 16 dry connections with drogue trailed by KC-130J Super Hercules tanker, while January 2006 programme involved F/A-18E Super Hornet deploying drogue from refuelling pod. Additional testing is expected to be performed by Naval Air Systems Command. Hamilton Sundstrand/Ratier Figeac NP2000 eight-blade, all-composites propeller flight tested on E-2C 163535 starting on 19 April 2001, following successful ground running on T56 and completion of critical design review in September 1998, with carrier suitability evaluation in USS John F Kennedy in November 2003. Fleet introduction began in 2004, with VAW-124 being one of first operational squadrons to receive new propeller; entire fleet to be retrofitted by end of 2006, with NP2000 also installed on French and Taiwanese Hawkeyes in 2005. In 2002, US Navy requested Northrop Grumman to undertake studies into possibility of adopting a new engine, although current plans do not include a change of engine. E-2D will have option to incorporate additional fuel cells in fixed outer wing section, extending mission duration by three hours.

ACCOMMODATION: Normal crew of five, consisting of pilot and co-pilot on flight deck, plus ATDS Combat Information Center (CIC) staff of combat information centre officer, air control officer and radar operator. Downward-hinged door, with built-in steps, on port side of centre-fuselage and three overhead escape hatches.

SYSTEMS: Pneumatic boot de-icing on wings, tailplane and fins. Spinners and blades incorporate electric anti-icing. Hamilton Sundstrand 255 kVA generator to be installed on E-2D.

AVIONICS: Comms: AN/AIC-14A intercom. AN/ARC-210 wideband/narrowband radio installed on Hawkeye 2000.
Radar: Lockheed Martin AN/APS-145 advanced radar processing system (ARPS) with fully automatic overland/overwater detection capability, Randtron AN/APA-171 rotodome (radar and IFF antennas). New Lockheed Martin AN/APY-9 radar being developed for installation on E-2D.
Flight: Lockheed Martin AN/ASN-92 CAINS carrier aircraft inertial navigation system, GPS, AN/ASN-50 heading and attitude reference system, Rockwell Collins AN/ARA-50 UHF ADF, AN/ASW-25B ACLS, BAE Systems standard central air data computer, ASM-400 in-flight performance monitor, Honeywell AN/APN-171(V) radar altimeter.
Instrumentation: Smiths Aerospace flight management and integrated standby instrument systems to be installed on E-2D.
Mission: BAE Systems/Hazeltine AN/APA-172 control indicator group with Lockheed Martin enhanced (colour) main display units (EMDU), which being replaced by L-3 Communications flat panel display screen during 2000-07, Litton OL-77/ASQ computer programmer (L-304) with Lockheed Martin enhanced high-speed processor, BAE Systems/Hazeltine OL-483/AP airborne interrogator system, Litton AN/ALR-73 passive detection system, AN/ARC-158 UHF datalink, AN/ARQ-34 HF datalink and JTIDS Class 2 HP terminal. Barco Display Systems graphics controllers with radar display capability and colour flat panel displays on Hawkeye 2000. Hawkeye 2000 also has AN/ALQ-217 ESM in place of AN/ALR-73 and Multi-Mission Advanced Tactical Terminal (MATT) for data communications.

DIMENSIONS, EXTERNAL:

• Wing span: 24.56 m (80 ft 7 in)
• Wing chord: at root: 3.96 m (13 ft 0 in)
• at tip: 1.32 m (4 ft 4 in)
• Wing aspect ratio: 9.3
• Width, wings folded: 8.94 m (29 ft 4 in)
• Length overall: 17.60 m (57 ft 8¾ in)
• Height overall: 5.58 m (18 ft 3¾ in)
• Diameter of rotodome: 7.32 m (24 ft 0 in)
• Tailplane span: 7.99 m (26 ft 2½ in)
• Wheel track: 5.93 m (19 ft 5¾ in)
• Wheelbase: 7.06 m (23 ft 2 in)
• Propeller diameter: 4.11 m (13 ft 6 in)

AREAS:

• Wings, gross: 65.03 m² (700.0 sq ft)
• Ailerons (total): 5.76 m² (62.00 sq ft)
• Trailing-edge flaps (total): 11.03 m² (118.75 sq ft)
• Fins, incl rudders and tabs:
• outboard (total): 10.25 m² (110.36 sq ft)
• inboard (total): 4.76 m² (51.26 sq ft)
• Tailplane: 11.62 m² (125.07 sq ft)
• Elevators: 3.72 m² (40.06 sq ft)

WEIGHTS AND LOADINGS:

• Weight empty: 18,363 kg (40,484 lb)
• Max fuel weight (iternal, usable): 5,624 kg (12,400 lb)
• Max T-O weight: 24,687 kg (54,426 lb)
• Max wing loading: 379.6 kg/m² (77.75 lb/sq ft)
• Max power loading: 3.25 kg/kW (5.34 lb/ehp)

PERFORMANCE:

• Max level speed: 338 kt (626 km/h; 389 mph)
• Max cruising speed: 325 kt (602 km/h; 374 mph)
• Cruising speed: normal: 259 kt (480 km/h; 298 mph)
• ferry: 268 kt (496 km/h; 308 mph)
• Approach speed: 103 kt (191 km/h; 119 mph)
• Stalling speed (landing configuration): 75 kt (138 km/h; 86 mph)
• Service ceiling: 11,275 m (37,000 ft)
• Min T-O run: 564 m (1,850 ft)
• T-O to 15 m (50 ft): 793 m (2,600 ft)
• Min landing run: 439 m (1,440 ft)
• Ferry range: 1,541 n miles (2,854 km; 1,773 miles)
• Time on station, 175 n miles (320 km; 200 miles) from base: 4 h 24 min
• Endurance with max fuel: 6 h 15 min