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|  موضوع: رد: طائرات الاستطلاع و الانذار المبكر Hawkeye 2000  الجمعة 12 نوفمبر 2010 - 10:48 | |
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Northrop Grumman E-2A/B/C/D HawkeyeThe harsh lesson of what can happen when a naval task force gets involved in a shooting war without an effective Airborne Early Warning (AEW) system was drawn into sharp focus during the Falklands War of 1982. In this conflict, played out in the unforgiving climate of the South Atlantic, the inability of the RAF to provide AEW cover with their antiquated Avro Shackleton AEW Mk2 aircraft from a nearby land base as planned, left the Royal Navy (RN) taskforce dangerously exposed and had a direct impact when HMS Sheffield and the Atlantic Conveyer were lost to attacks by low-flying by Super Etendard aircraft launching Exocet missiles.As far back as 1942 the US Navy had recognised the treat posed by low-flying aircraft approaching a naval task force underneath radar cover, which is limited to a radar horizon of around 30 miles, giving little warning of an impending attack. This requirement led to Admiral Ernest J King, the US Navy C-in-C of the US Navy, to issue a request to Dr Vannevar Bush, the director of the Office of Scientific Research and Development (ORSD) to develop a radar-relay system which would allow the exchange of radar information between ships. The radar-relay project, NA-112 was established in June 1942, with D Division of the Massachusetts Institute of Technology – Radiation Laboratory (MIT-RL) doing much of the initial work, but made slow progress. In early 1944, following a review of the progress of NA-112, it was decided to change the focus of the project away from a radar-relay system to the development of an AEW system, renamed Project NA-178, with the MIT-RL again leading the work. In Feb 1945 the development programme was renamed Project Cadillac, after Cadillac Mountain in Maine where much of the early testing was conducted.  The AEW radar developed under Project Cadillac was known as the APS-20 and during 1944 it was mounted in a General Motors TBM Avenger and as the TBM-3W this became the first AEW aircraft to undergo testing. The APS-20 radar was one of the great scientific developments of WW2, but was still undergoing testing when the war ended. The radar operated in the S-Band and featured a 8ft by 3ft parabolic dish antenna mounted in a plastic fairing underneath the aircraft, giving 360 degree coverage. The radar system also incorporated various highly advanced innovations including an Identification Friend or Foe (IFF) as well as a transmitter that relayed both the radar picture and the IFF information to receiver stations onboard adjacent ships. The relay transmission system was called ‘Bellhop’, but it was a long time before it operated effectively. Two operators worked the radar and ‘Bellhop’ system, but excessive clutter, the lack of an automatic tracking system and symbology were significant weaknesses – radar returns were manually tracked by drawing marks with a chinagraph pencil on the screen itself, significantly limiting the capacity of the operators.  Under a programme known as Cadillac II, the Navy also fitted the APS-20 radar system onto the B-17G aircraft, giving it the designation PB-1W, but although this aircraft had much greater endurance and could carry a larger crew, it could not operate from a carrier deck and entered operational service after the war in the Pacific was over. The US Navy also investigated the benefits of mounting the APS-20 on an airship and although this platform could offer much greater endurance, it still possessed many of the weakness of the PB-1W. Eventually a number of carrier capable Grumman AF-2W Guardians were equipped with the APS-20 radar, but the US Navy seemed intent on using the AEW capabilities of the aircraft in other roles and mainly employed the aircraft in partnership with an anti-submarine version of the same aircraft, known as the AF-2S, to located and destroy enemy submarines.      However, although the upgraded E-2B was a vast improvement on the unreliable E-2A, the US Navy knew the design had much greater capability and still had yet to achieve the performance and reliability parameters set out in the original design back in 1957. In Apr 1968 it instigated the next reliability improvement programme. In addition, now that the capabilities of the aircraft were starting to be realised, more were needed and, as well as the 49 E-2Bs that would be upgraded, another 28 new E-2Cs were ordered. The improvements in the new and upgraded aircraft were concentrated in the radar and computer performance. The new General Electric AN/APS-120 UHF radar was fitted to all the aircraft and this incorporated an Airborne Moving Target Indicator (AMTI), finally giving the aircraft an overland capability and included a linked AN/APS-72 or 76 IFF. Additional Litton L-304 computers were also fitted to increase the signal processing capability. Of probably even greater significance was the installation in the nose of the Litton AN/ALR-59 Passive Detection System (PDS) Electronic Support Measures (ESM) which enabled the aircraft to detect other radar or radio systems at very long ranges, before they had any possibility of detecting the Hawkeye. Further interceptions by the PDS allowed the source of the signal to be triangulated, revealing its location. The problem associated with increased heat generated by the additional electrical systems was solved by adding an additional air-scoop housing a vapour cycle cooling system condenser. To compensate for the increased weight, the engines were replaced by more powerful T56-A-425 turboprops. When it was finally introduced into service in 1974, the E-2C possessed a unique capability and was by some distance the best AEW system in the world; at last all the delays and problems experienced during the lengthy development programme were beginning to pay off.      The other really noticeable change in the Hawkeye 2000 is the replacement of the old four-bladed propellers, which were no longer in production, with eight-bladed Hamilton Standard NP2000 composite propellers. The new propellers are more efficient, give less vibration and are quieter and also allow individual blades to be changed. The first Hawkeye 2000, which still retained the E-2C designation, was delivered in Oct 01 and the new variant reached initial operating capability in 2003. Original planes called for the E-2C Group 2 aircraft to be upgraded to the Hawkeye 2000 standard; however, this was later replaced by a plan for a multi-year production of new Hawkeye 2000 aircraft, with the factory at Northrop Grumman’s plant at St Augustine, Florida producing four aircraft per year. To reflect the new capabilities of these aircraft, the US Navy AEW squadrons are now known as Battle Management Command and Control Squadrons.  Inside the CIC new larger displays will be installed and additional communications facilities will be added. These include a new computer system which will act like a ‘server in the sky’ for other aircraft, including UAVs, enabling much greater network connectivity. In the cockpit the old 1960s style analogue instruments will be replaced by three multi-functional 17in flat screen displays, enabling the co-pilot to act as a fourth operator during the mission. An in-flight refuelling probe will be added at a later date, once issues concerning the effect the jet efflux from the Boeing F/A-18E Super Hornet on the rotodome have been resolved. Until 23 Sep 2005 the US Navy Hawkeye’s were organised into east and west coast wings, supporting the Atlantic and Pacific fleets respectively. However, the east coast wing has now been disestablished and all aircraft are now organised into a single wing based at Point Mugu, California. Construction of the first E-2D began in Apr 05 and the first flight is expected to take place in Aug 07. Initial operating capability is scheduled for 2011 and under current plans a total of 75 aircraft will be built, equipping 12 squadrons with four aircraft each. Currently a four aircraft detachment equips each Carrier Battle Group, although the greater use these highly capable aircraft will be put through have led some calls for the detachment size to be increased to six aircraft.  The success of the E-2 Hawkeye led to many other countries wanting to acquire an AEW capability and they watched the development of the aircraft carefully. However, the USA has, quite rightly, always been very careful which country it allows to acquire any new advanced military capability, furthermore, it wasn’t until the appearance of the E-2C that the system was actually sufficiently robust to attract an export order. The Israeli Air Force (IAF) was the first export customer and received four E-2C Group 0 aircraft between 1977 and 1978 where they were known in Hebrew as the ‘Daya’ or Kite and given the designations 941, 942, 944 and 946. The IAF locally fitted in-flight refuelling probes to two of these aircraft to extend their time on-station. These aircraft played a major part in the Beka Valley battles of 1982 where, in a carefully co-ordinated attack, the Syrian Air Force (SAF) were drawn into the air and destroyed en-mass by IAF F-15s and F-16s guided onto their targets by the Hawkeye’s. The effect of this utter annihilation of the cream of the SAF, where a total of 85 aircraft were eventually lost, was so traumatic that they have never again attempted to challenge the IAF.  However, the IAF E-2Cs were still optimised for over-sea, rather than over-land operations and although they were later modified by some locally produced avionics to improve their performance, they still lacked many of the capabilities the IAF wanted. To overcome these deficiencies the Israeli defence industry was developing the Phalcon AEW&C system and, when this became operational in 1994, the four E-2Cs were retired and became surplus to requirements.  Japan was the next customer acquiring eight E-2C Group 0 aircraft between 1982 – 1985, followed by five more between 1992-3. All the aircraft are operated by 601 Hikotai, Keikai Kokutai (AEW Air Group) located at Misawa in northern Honshu. Japan originally planned to upgrade these aircraft to Group 2 standard, but instead opted up upgrade all 13 aircraft to the Hawkeye 2000 standard in a rolling programme, with the first refurbished aircraft flying on 14 Jul 04.In 1987, following Japan’s example, Singapore acquired four Group 0 Hawkeye’s. The aircraft have been continually upgraded throughout their service and are currently up to Hawkeye 2000 standard – all four Hawkeye’s are operated by the 111th Squadron based at Tengah.Egypt was the next customer for the Hawkeye when they took delivery of five Group 0 aircraft in 1986, followed by one other Group 2 aircraft in 1993 - all the aircraft are operated by the 222 Fighter Regiment located at Almaza/Cairo West airbase. The six aircraft are in the process of being upgraded to Hawkeye 2000 standard, with the final aircraft being returned to Egypt in Apr 2007.In 1995 Taiwan took delivery of four new built E-2C Group 2 aircraft which are operated by 78 Squadron based at Pingtung North. Two further Hawkeye 2000’s were delivered between 2004-5. All four of the Group 2 aircraft will be upgraded to Hawkeye 2000 standard between 2006-7.   The RN are currently studying various AEW&C options, to replace their Sea King ASaC.7 helicopters, under the Maritime Airborne Surveillance and Control (MASC) programme, hopefully to operate from the highly controversial two large carriers planned to replace the three Invincible class carriers. Much as the RN would love to operate the E-2D from these carriers, it’s very unlikely they will be fitted with catapults or arrestor wires, making the operation of fixed wing AEW aircraft impossible. Allowing the RN to operate the latest standard of Hawkeye, with the increased ease of intra-operability with US forces that would bring, from the decks of the new carriers would make considerable sense. However, desirable military requirements rarely emerge victorious in a battle with the Treasury ‘bean-counters’ and even if the two carriers are built, which is by no means certain, I expect they will end up operating Merlin ASaC helicopters alongside Joint Strike Fighters.  The capabilities of the Hawkeye were extended yet again in 2003, during Operation Enduring Freedom in Afghanistan. In this theatre Hawkeye’s from the USS Enterprise, operating from Bagram Air Base in Afghanistan, performed the Airborne Battlefield Command, Control and Communications (ABCCC) role in support of ground forces, enabling communications to be maintained in the mountainous terrain, allocating aircraft and helicopters into the battlespace as well as co-coordinating requirements from Forward Air Controllers. In summary, the E-2 Hawkeye has become a combination of a smaller version of a combined E-3 and J-STARS, a capability few would ever have imagined possible and versions of this remarkable aircraft will be around for many years to come.
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