Hawker Siddeley Nimrod ұшқыштарының тарихы

Maritime patrol aircraft family by Hawker Siddeley, later British Aerospace
a jet engine maritime patrol aircraft

{|Infobox aircraft type
|type= Maritime patrol aircraft
|national origin = United Kingdom
|manufacturer= Hawker SiddeleyBAE Systems
|designer=
|first flight= 23 May 1967
|introduced= 2 October 1969
|retired= 28 June 2011 The intended replacement was to be extensively rebuilt Nimrod MR2s, designated Nimrod MRA4. Due to considerable delays, repeated cost overruns, and financial cutbacks, the development of the MRA4 was abandoned in 2010. The RAF also operated a small number of the Nimrod R1, an electronic intelligence gathering (ELINT) variant. A dedicated airborne early warning platform, the Nimrod AEW3, was in development from late 1970s to the mid 1980s; however, much like the MRA4, considerable problems were encountered in development and thus the project was cancelled in 1986 in favour of an off the shelf solution in the Boeing E 3 Sentry. All Nimrod variants had been retired by mid 2011.

On 4 June 1964, the British Government issued Air Staff Requirement 381, which sought a replacement for the aging Avro Shackleton maritime patrol aircraft of the Royal Air Force (RAF). Such a replacement had been necessitated by the rapidly approaching fatigue life limitations accumulated across the Shackleton fleet. A great deal of interest in the requirement was received from both British and foreign manufacturers, who offered aircraft including the Lockheed P 3 Orion, the Breguet Atlantic and derivatives of the Hawker Siddeley Trident, BAC One Eleven, Vickers VC10 and de Havilland Comet. On 2 February 1965, Prime Minister Harold Wilson announced the intention to order Hawker Siddeley's maritime patrol version of the Comet, the HS.801 as a replacement for Shackleton Mk 2. refn|Following evaluation testing by the RAF, the Vickers VC10 had been identified as highly suitable for the task; however, an initial version of Comet based Nimrod could be in service within five years, a more capable Nimrod equipped with the envisioned avionics would follow. The first example (XV230) entered service in October 1969.

Three Nimrod aircraft were adapted for the signals intelligence role, replacing the Comet C2s and Canberras of No. 51 Squadron in May 1974. The R1 was visually distinguished from the MR2 by the lack of a MAD boom. It was fitted with an array of rotating dish aerials in the aircraft's bomb bay, with further dish aerials in the tailcone and at the front of the wing mounted fuel tanks. It had a flight crew of four (two pilots, a flight engineer and one navigator) and up to 25 crew operating the SIGINT equipment. Only since the end of the Cold War has the role of the aircraft been officially acknowledged; they were once described as "radar calibration aircraft". The R1s have not suffered the same rate of fatigue and corrosion as the MR2s. One R1 was lost in a flying accident since the type's introduction; this occurred in May 1995 during a flight test after major servicing, at RAF Kinloss. To replace this aircraft an MR2 was selected for conversion to R1 standard, and entered service in December 1996. The Nimrod R1 was based initially at RAF Wyton, Cambridgeshire, and later at RAF Waddington, Lincolnshire, and flown by 51 Sqn. The two remaining Nimrod R1s were originally planned to be retired at the end of March 2011, but operational requirements forced the RAF to deploy one to RAF Akrotiri, Cyprus on 16 March in support of Operation Ellamy. The last flight of the type was on 28 June 2011 from RAF Waddington, in the presence of the Chief of the Air Staff, ACM Sir Stephen Dalton. XV 249, the former MR2, is now on display at the RAF Museum Cosford, West Midlands. The R1 was replaced by three Boeing RC 135W Rivet Joint aircraft, acquired under the Airseeker project; the first aircraft was delivered in late 2013.

Starting in 1975, 35 aircraft were upgraded to MR2 standard, being re delivered from August 1979. The upgrade included extensive modernisation of the aircraft's electronic suite. Changes included the replacement of the 1950s ASV Mk 21 radar used by the Shackleton and Nimrod MR1 with the new EMI Searchwater radar, a new acoustic processor (GEC Marconi AQS 901) capable of handling more modern sonobuoys, a new mission data recorder (Hanbush) and a new Electronic Support Measures (Yellow Gate) which included new pods on the wingtips. Provision for in flight refuelling was introduced during the Falklands War (as the MR2P), as well as hardpoints to allow the Nimrod to carry the AIM 9 Sidewinder missile to counter enemy Argentine Air Force maritime surveillance aircraft. In preparation for operations in the Gulf War theatre, several MR2s were fitted with new communications and ECM equipment to deal with anticipated threats; at the time these modified aircraft were given the designation MR2P(GM) (Gulf Mod). The last official flight of a Nimrod MR2 took place on 26 May 2010, with XV229 flying from RAF Kinloss to Kent International Airport to be used as an evacuation training airframe at the nearby MOD Defence Fire Training and Development Centre.

In the mid 1970s a modified Nimrod was proposed for the Airborne Early Warning (AEW) mission – again as a replacement for the Lancaster derived, piston engined Shackleton AEW.2. Eleven existing Nimrod airframes were to be converted by British Aerospace to house the GEC Marconi radars in a bulbous nose and tail. The Nimrod AEW3 project was plagued by cost over runs and problems with the GEC 4080M computer used. Eventually, the MoD recognised that the cost of developing the radar system to achieve the required level of performance was prohibitive and the probability of success very uncertain, and in December 1986 the project was cancelled. The RAF eventually received seven Boeing E 3 Sentry aircraft instead. Some functions were allocated to other assets, with Hercules transport aircraft and E 3 Sentry Airborne Early Warning aircraft given some tasks, but the cancellation of the MRA4 resulted in a significant gap in long range maritime patrol and search and rescue capability. In July 2016, the Ministry of Defence announced the purchase of nine Boeing P 8A Poseidon aircraft for the RAF. The RAF declared the P 8 had reached initial operating capability (IOC) on 1 April 2020, by which time two of the planes had been delivered. The nine aircraft will be based at RAF Lossiemouth.

The Nimrod was the first jet powered MPA to enter service, being powered by the Rolls Royce Spey turbofan engine. Aircraft in this role had been commonly propelled by piston or turboprop powerplants instead to maximise fuel economy and enable maximum patrol time on station. Advantages of the Nimrod's turbofan engines included greater speed and altitude capabilities, and it was more capable of evading detection by submarines, as propeller driven aircraft are more detectable underwater by standard acoustic sensors. The Nimrods had a flight endurance of ten hours without aerial refuelling. The MR2s were later fitted to receive mid air refuelling in response to demands of the Falklands War. Similarly, the two hydraulic systems on board were designed to be powered by the two inner engines that would always be running. A significant proportion of the onboard sensor equipment was housed outside the pressure shell inside the Nimrod's distinctive pannier lower fuselage. The Nimrod and its detection capabilities were an important component of Britain's military defence during the height of the Cold War. The Nimrod's navigational functions were computerised, and were managed from a central tactical compartment housed in the forward cabin. Various functions such as weapons control and information from sensors such as the large forward doppler radar were displayed and controlled at the tactical station. The flight systems and autopilot could be directly controlled by navigator's stations in the tactical compartment, giving the navigator nearly complete aircraft control. Upon entry into service, the Nimrod was hailed as possessing advanced electronic equipment such as onboard digital computers. The increased capability of these electronic systems allowed the RAF's fleet of 46 Nimrod aircraft to provide equal coverage to that of the larger fleet of retiring Avro Shackletons. After a mission, gathered information could be extracted for review purposes and for further analysis.

The Nimrod featured a sizeable bomb bay in which, in addition to armaments such as torpedoes and missiles, could be housed a wide variety of specialist equipment for many purposes, such as up to 150 sonobuoys for ASW purposes or multiple air deployed dinghies and droppable survival packs such as Lindholme Gear for SAR missions; additional fuel tanks and cargo could also be carried in the bomb bay during ferrying flights. Various new ECMs and electronic support systems were retrofitted onto the Nimrod fleet in response to new challenges and to increase the type's defensive capabilities; additional equipment also provided more effective means of identification and communication. A number of modifications were introduced during the 1991 Gulf War; a small number of MR2s were fitted with improved Link 11 datalinks, new defensive ECM equipment including the first operational use of a towed radar decoy, and a forward looking infrared turret under the starboard wing. The majority of the Nimrod fleet operated from RAF Kinloss in Scotland. Operationally, each active Nimrod would form a single piece of a complex submarine detection and monitoring mission. An emphasis on real time intelligence sharing was paramount to these operations; upon detecting a submarine, Nimrod aircrews would inform Royal Navy frigates and other NATO aligned vessels to pursuit in an effort to continuously monitor Soviet submarines. The safeguarding of the Royal Navy's Resolution class ballistic missile submarines, which were the launch platform for Britain's nuclear deterrent, was viewed as being of the utmost priority.

Nimrods were first deployed to Wideawake airfield on Ascension Island on 5 April 1982, the type at first being used to fly local patrols around Ascension to guard against potential Argentine attacks, and to escort the British Task Force as it sailed south towards the Falklands, with Nimrods also being used to provide search and rescue as well as communications relay support of the Operation Black Buck bombing raids by Avro Vulcans. As the Task Force neared what would become the combat theatre and the threat from Argentine submarines rose, the more capable Nimrod MR2s took on operations initially performed by older Nimrod MR1s. Aviation author Chris Chant has claimed that the Nimrod R1 also conducted electronic intelligence missions operating from Punta Arenas in neutral Chile. The Chilean government allowed an RAF Nimrod R1 to fly signals reconnaissance sorties from the Desventuradas Islands, gathering information on Argentine Air Force movements. The addition of air to air refuelling probes allowed operations to be carried out in the vicinity of the Falklands, while the aircraft's armament was supplemented by the addition of general purpose bombs, BL755 cluster bombs and AIM 9 Sidewinder air to air missiles. The use of air to air refuelling allowed extremely long reconnaissance missions to be mounted, one example being a 19 hour 5 minute patrol conducted on 15 May 1982 (XV232 Airborne: 0803, Landing: 0308), which passed within 60 mile (97 km) of the Argentine coast to confirm that Argentine surface vessels were not at sea. Another long range flight was carried out by an MR2 on the night of 20/21 May, covering a total of , the longest distance flight carried out during the Falklands War. In all, Nimrods flew 111 missions from Ascension in support of British operations during the Falklands War.

A detachment of three Nimrod MR2s was deployed to Seeb in Oman in August 1990 as a result of the Iraqi invasion of Kuwait, carrying out patrols over the Gulf of Oman and Persian Gulf. Due to the level of threats present in the Gulf theatre, operational Nimrods were quickly retrofitted with a Marconi towed active decoy. Once hostilities commenced, the Nimrod detachment, by now increased to five aircraft, concentrated on night patrols, with daylight patrols carried out by US Navy Lockheed P 3 Orions. Nimrods were used to guide Westland Lynx helicopters and Grumman A 6 Intruder attack aircraft against Iraqi patrol vessels, being credited with assisting in sinking or damaging 16 Iraqi vessels. After the ground offensive against Iraqi forces had ended, Britain elected to maintain an RAF presence in the region through assets such as the Nimrod and other aircraft. Nimrod R1s operated from August 1990 to March 1991 from Cyprus, providing almost continuous flying operations from the start of the ground offensive. Each R1 was retrofitted with the same Marconi towed active decoy as well as under wing chaff/flare dispensers, reportedly sourced from the Tornado fleet.

Nimrods were again deployed to the Middle East as part of the British contribution to the US led invasion of Afghanistan; missions in this theatre involved the Nimrods performing lengthy overland flights for intelligence gathering purposes. On 2 September 2006, 14 UK military personnel were killed when a Nimrod MR2 was destroyed in a midair explosion following an onboard fire over Afghanistan. It was the single greatest loss of British military lives since the Falklands War. The outbreak of the Iraq War in March 2003 saw the RAF's Nimrods being used for operations over Iraq, using the aircraft's sensors to detect hostile forces and to direct attacks by friendly coalition forces.

While the Nimrod MR1/MR2 was in service, one aircraft from each of the squadrons on rotation was available for search and rescue operations at one hour standby. The standby aircraft carried two sets of Lindholme Gear in the weapons bay. Usually one other Nimrod airborne on a training mission would also carry a set of Lindholme Gear. As well as using the aircraft sensors to find aircraft or ships in distress, it was used to find survivors in the water, with a capability to search areas of up to 20000 square miles (51,800 km2). The main role would normally be to act as on scene rescue coordinator to control ships, fixed wing aircraft, and helicopters in the search area. The Nimrod was most often featured in the media in relation to its search and rescue role, such as in the reporting of major rescue incidents. In August 1979, several Nimrods were involved in locating yachting competitors during the disaster stricken 1979 Fastnet race and coordinated with helicopters in searches for survivors from lost vessels. In March 1980, the Alexander L. Kielland, a Norwegian semi submersible drilling rig, capsized whilst working in the Ekofisk oil field killing 123 people; six different Nimrods searched for survivors and took turns to provide rescue co ordination, involving the control of 80 surface ships and 20 British and Norwegian helicopters. In an example of its search capabilities, in September 1977 when an attempted crossing of the North Atlantic in a Zodiac inflatable dinghy went wrong, a Nimrod found the collapsed dinghy and directed a ship to it. The whole area was routinely patrolled. In addition to surveillance, the aircraft would communicate with all oil and gas platforms. During the Icelandic Cod Wars of 1972 and 1975–1976, the Nimrod fleet closely cooperated with Royal Navy surface vessels to protect British civilian fishing ships.

Type Role Number Built NotesHS.801Prototype2Built using redundant Comet 4 airframesMR.1Anti submarine Warfare46R.1Signals Intelligence4One converted from MR.2MR.2Anti submarine warfare35Modernised MR.1 aircraftAEW.3Airborne early warning11Converted from redundant MR.1 aircraft; project cancelledMRA.4Anti submarine warfare5Converted from MR.2; 21 planned; project cancelled