Nimrod 'The Mighty Hunter'

He was a mighty hunter before the Lord; therefore it is said, "Like Nimrod the mighty hunter before the Lord." Genesis 10:9

In July 1963 Air Staff Target No 357 (AST 357) was issued; AST 357 defined the requirements for a maritime reconnaissance aircraft to replace the Shackleton by the year 1972. Later, in October 1963, Hawker Siddeley submitted a feasibility study of a number of aircraft to meet that requirement. Shortly afterwards, the Ministry of Aviation asked the company to advise the possibility of producing an aircraft to meet an in-service date of 1968. Although no written requirement was issued for this earlier aircraft, it was suggested by the Ministry that the main design aim should be to approach the AST 357 requirement as far as possible within the new time scale, and to take the fullest possible account of subsequent development potential.

In April 1964, Hawker Siddeley submitted its response to the request. Its proposal was the HS 800; a development of the Trident airliner to be fitted with the most advanced navigation, search and attack system that could be developed by 1968.

However, on the 17 June 1964 Hawker Siddeley was acquainted with the contents of a new requirement, Air Staff Requirement 381 (ASR 381), dated 4 June 1964. ASR 381 called for an interim aircraft to enter services in late 1966. The overall capability required of this aircraft was not in the same class as that defined in AST 357, in fact substantially less in all respects.

In July 1964, Hawker Siddeley produced a report offering the HS 801 as a possibility to meet the demands of ASR 381. The HS 801 was to be a Comet 4C conversion. As Treasury purse-strings gradually tightened, it made sound economic sense to use a tried and tested airframe. The Comet has an excellent record as both a military and civilian passenger transport, having accumulated some 1.5 million flying hours. Much of the structural design work, therefore, had already been proven, and existing jigs and a workforce familiar with production methods, could be utilised.

The Preliminary Type Specification was issued in October, followed by the completed Type Specification a couple of months later in December 1964. Issue Two of the Type Specification was made in May 1965 and in June 1965, approval was given for the initial work to commence. In January 1966 the Government decision was finally made to go ahead with the production of the aircraft, by now designated 'Nimrod'

The contract for most if the programme was negotiated on a fixed-price basis, amounting to about £100 million. This included design, research and development, two prototypes and the production of 38 aircraft.

The Preliminary Type Specification outlined a production timetable for two prototypes and 38 production aircraft based upon the Invitation To Progress (ITP). The programme was to utilise two Comet 4C airframes which were already available. The first of these was to have its fuselage shortened, and was to be equipped with a full maritime reconnaissance weapon system. Four Rolls Royce RB168-1, the military version of the Spey engine, were to be fitted and the intakes modified accordingly. This prototype was to be used as a systems development aircraft with the weapons pannier fitted but without operating doors. The initial flight of the systems development aircraft was to be 23 months after ITP.

The second existing Comet 4C airframe was to be modified to the same basic standard as the first. The entire weapons system was to be installed prior to the first flight together with a completely operational pannier and associated weapons carriers. The initial flight of this aircraft was to be 30 months after ITP.

The initial flight of the first production airframe was originally planned for 33 months after ITP, then to be followed by one aircraft every two months up to the fourth, and thereafter two aircraft per month. The complete build programme of 38 aircraft was scheduled to take 59 months from ITP.