TYPE: Multisensor surveillance twin-turboprop.

PROGRAMME: Marketing experience with BN2T Defenders revealed that many military and government agencies expressed need for greater payload; announced 1994; prototype (G-SURV) made first flight 17 August 1994; public launch at Farnborough Air Show September 1994; CAA certification achieved 13 November 1995; CAA transport (passenger) certification 4 April 1996.
Britten-Norman and Orenda Recip Inc of Canada announced in September 1999 joint study to re-engine Defender with Orenda OE600 V-8 piston engines, resulting in improved performance and efficiency. Projected specification includes maximum T-O weight 4,241 kg (9,350), maximum cruising speed 176 kt (326 km/h 202 mph) and maximum rate of climb 366 m (1,200 ft)/min.

CURRENT VERSIONS: BN2T-4S Defender 4000: Standard version, as described.
National Defender: Derivative version of Defender 4000 optimised for homeland defence role; features include increased sensor payload of 1,587 kg (3,499 lb).

CUSTOMERS: Seven aircraft registered to manufacturer in April 1996. Irish Ministry of Justice took delivery of one on 14 August 1997; aircraft is operated by the Irish Air Corps at Baldonnel, Dublin, on behalf of the Garda Siochana (National Police), and is equipped with a comprehensive suite of law enforcement communications equipment, thermal imager and observers' removable consoles. Sabah Air of Malaysia took delivery of one in November 1997; primarily equipped for aerial photographic work, with quick-change facility to 12-passenger transport. Police Aviation Services UK took delivery of a single (ex-demonstrator) example in November 1998, this later (2002) passed to Atlantic Air Transport, Coventry. Hampshire Police Authority took delivery of one (G-SJCH, named Sir John Charles Hoddinott) on 26 February 2001 for service with its Lee-on-Solent-based Air Support Unit, replacing a BN2B Islander. Greater Manchester Police ordered on (GMPB) on 15 January 2002, delivery of which was achieved on 2 July 2002.

COSTS: £2.5 million (2002). Direct operating cost (2003); £167.01 in 'cruise' operation or £147.52 in 'surveillance' role (900+ hours per year utilisation and 0.90 mmh/fh).

DESIGN FEATURES: As for Islander, but with enlarged wing, based on that of Trislander, although retaining original control surfaces; compared with BN2T, has tailplane and elevator of increased span; modified fin with larger fillet; fuselage stretched by means of 0.76 m (2 ft 6 in) plug forward of wing to seat up to 16; more powerful engines for greater sortie time and payload capacity; fuselage and landing gear strengthened; flight deck windows deepened for enhanced field of view; redesigned nose and tail unit; rear-sliding door with blister window.

POWER PLANT: Two Rolls-Royce 250-B17F turboprops, each flat rated at 298 kW (400 shp) and driving a three-blade propeller. Internal fuel capacity 1,131 litres (299 US gallons; 249 Imp gallons).

ACCOMMODATION: Flight crew of two on airline-type seats; sliding seat rails permit seat and equipment positioning anywhere within fuselage. Space for two or more consoles and operators in tandem along one side of cabin. Up to 16 troops/passengers in tactical transport role. Certified to carry pilot and 11 passengers, subject to local airworthiness requirements.

SYSTEMS: Electrical system includes two 200 A engine-driven generators. Full de-icing.

AVIONICS: Comms: Full range of open or secure voice com radios from UHF, VHF, HF and VHF-FM.
Radar: Modified nose can accommodate 68.5 cm (27 in), 360° rotating antenna for maritime, simple search or weather radar (BAE Systems Seaspray 2000 in prototype Defender 4000).
Flight: Fully integrated autopilot. GPS nav system, integrated with Omega or INS.
Mission: Sensors can include thermal imagers and/or hand-held or podded video or film cameras. Prototype on debut fitted with Agema FLIR under fuselage on starboard side; alternatives could include BAE Systems pod or FLIR 2000. Appropriate radars could include BAE Systems Seaspray, Racal Super Searcher. Thomson-CSF Detexis Ocean Master, Telephonics 143 or Litton 504(V)5.

ARMAMENT: Two hardpoints under each wing, inboard pair stressed for loads of up to 340 kg (750 lb) and outboard pair for up to 159 kg (350 lb) each. Typical weapons on inboard stations can include Sting Ray torpedo or Sea Skua anti-ship missile.