Hawker Siddeley Nimrod

 

The Hawker Siddeley Aircraft Nimrod maritime patrol aircraft was an extensive modification of the De Havilland 106 Comet 4. On 4 June 1964, the British Government issued Air Staff Requirement 381, which sought a replacement for the aging Avro Shackleton maritime patrol aircraft which was fast approaching its fatigue life limit.

 

The Nimrod was originally designed by Hawker Siddeley with further development by British Aerospace and BAE Systems. 

 

The first two prototypes, designated Hawker Siddeley HS801, were modifications of unsold De Havilland 106 Comet 4C airframes, retained at the Hawker Siddeley Chester factory. These aircraft (serials XV147 and XV148) can generally be distinguished by their retention of the original airliner passenger windows. The first Hawker Siddeley HS801 prototype flew on 24th May 1967.

 

Compared with the DH Comet, the HS801 Nimrod was fitted with Rolls-Royce Spey engines, featuring a new lower fuselage, containing a forward-looking search radar and a lengthy sonobuoy and weapons bay. A magnetic anomaly detector (MAD) sting was mounted in the extreme tail, with electronic surveillance sensors mounted in a fairing at the top of the tail fin.

 

The HS801 Nimrod was designed to replace the Avro Shackleton in its maritime patrol and anti-submarine operations, with secondary roles including anti-ship operations and long-range search and rescue support.

 

HS801 Nimrod MR1: The initial service variant was the HS801 Nimrod MR.1, of which 46 were ordered during 1967, with the first service aircraft (XV230) being delivered in October 1969. Compared with the prototypes, this production aircraft featured a reduced number of cabin windows.

 

 

HS801 Nimrod R1: Three HS801 Nimrod MR1 aircraft were adapted for the signals intelligence (SIGINT) role and designated HS801 Nimrod R1. The HS801 R1 was visually distinguished from the HS801 Nimrod MR2 by the lack of the rear MAD boom, together with the introduction of a number of additional external aerials, mounted on the upper and lower fuselage. Additional internal rotating dish aerials were fitted in the weapons bay, within the rear fuselage and in the front of the wing-mounted pinion tanks.  

 

It had a flight crew of four (two pilots, a flight engineer and one navigator) and up to 25 crew operating the mission equipment.

 

 

Following the loss of one aircraft in May 1995, a replacement aircraft was generated by the conversion of HS801 Nimrod MR.2 (XV249). This HS801 Nimrod R1 was flown by 51 Sqn RAF, intitially from RAF Wyton but later from RAF Waddington. The last flight of the type was on 28th June 2011 and the aircraft (XV 249) is now preserved at the RAF Museum Cosford, West Midlands.

 

HS801 Nimrod MR2: From 1975, 35 HS801 Nimrod MR1 aircraft were upgraded to HS801 Nimrod MR2 standard. This upgrade included extensive modernisation of the aircraft's electronic mission equipment. It also added the new EMI Searchwater radar, a new acoustic processor (GEC-Marconi AQS-901), a new mission data recorder and new Electronic Support Measures equipment (Yellow Gate).

 

The HS801 Nimrod MR2 carried a flight crew of two pilots, one flight engineer and two navigators (one tactical navigator and a routine navigator), with a mission crew comprising of one Air Electronics Officer (AEO), the sonobuoy sensor team of two Weapon System Operators and finally four EW System Operators to manage passive and active electronic warfare systems.

 

 

The Falklands War resulted in the provision of in-flight refuelling equipment and so am HS801 was quickly adapted as the HS801 Nimrod MR2P. The aircraft was also equipped with the ability to carry the AIM-9 Sidewinder missile for self-defence. Further equipment changes were introduced to support operations in the Gulf theatre.

 

The HS801 Nimrod MR2 fleet was based at RAF Kinloss in Scotland (with 120, 201 and 206 Squadrons), and RAF St Mawgan in Cornwall (with 42 and 38(R) Squadrons). The HS801 Nimrod MR2 aircraft was withdrawn at the end of March 2010 and with it 42 Squadron was disbanded and amalgamated with 38(R) Squadron.

 

The HS801 Nimrod MR2 aircraft was fully withdrawn a year earlier than planned (for financial reasons) and the last official flight (XV229) took place on 26th May 2010, flying from RAF Kinloss to Kent International Airport at Manston whereafter it was used as an evacuation training airframe at the Ministry of Defence Fire Training and Development Centre.

 

 In the mid-1970s, a modified HS801 Nimrod was proposed for the Airborne Early Warning (AEW) mission, as a replacement for the long-serving Avro Shackleton AEW.2.

 

Eleven existing HS801 Nimrod airframes were to be converted by British Aerospace at Woodford  predominately to house the GEC Marconi radars, accommodated in bulbous nose and tail radomes. The British Aerospace Nimrod AEW3 project suffered numerous delays, predominantly due to technical problems with the integration of the mission equipment. This resulted in the cancellation of the programme in December 1986.

 

 

The BAE Systems Nimrod MRA4 was intended to replace the capability provided by the HS801 MR2.

 

Essentially it was a new aircraft, with the more efficient Rolls-Royce BR710 turbofan engines, installed in a new larger wing, with a fully refurbished fuselage. The first prototype of the BAE Systems Nimrod MRA4 (ZJ516) flew for the first time on 26th August 2004.

 

 

Significant delays and cost overruns were encountered and the BAE Systems Nimrod MRA4 programme was dramatically reduced in scope.

 

Following the latest Strategic Defence and Security Review (SDSR), the 9 aircraft program was cancelled on 19th October 2010, resulting in some significant loss of operational capability. At the time of cancellation, three development aircraft and two production aircraft had been flown.

 

The purchase of nine Boeing P-8A Poseidon aircraft is intended to restore the UK’s long-range maritime patrol capability.