Britten-Norman Islander BN-2T-4S Defender 4000

The Defender 4000 is where the BN-2 line strays furthest from its origin. On the turboprop Defender's foundation Britten-Norman stretched the fuselage, borrowed the Trislander's larger wing and designed a new nose able to house an electro-optical and infrared turret plus radar. The result is twelve metres long with a span of just over sixteen, nearly four tonnes of maximum take-off weight and more than eight hours of endurance: a persistent surveillance aircraft rather than a utility machine with sensors bolted on.

In January 2004 the British Army placed an urgent order for four Defender 4000s designated AL Mk 1 for ISTAR missions in Iraq. The first was delivered that October to No. 1 Flight of the Army Air Corps and the last in September 2006 to 651 Squadron, reformed to operate the type, fitted with a Wescam MX-15 turret under the nose, cabin-mounted cameras and communications-intelligence and command-and-control equipment. A second order for four fully redesigned aircraft produced the Mk 2, with longer endurance and improved avionics, and a T Mk 3 trainer.

The Iraq deployment ended in June 2009 after almost five years of continuous service and more than eight thousand flying hours in support of British forces. Afghanistan followed between 2010 and 2012, along with daily sorties over London during the 2012 Olympic Games. In April 2019 the type passed from the Army to the Royal Air Force and the AL2 designation gave way to R2; in June 2021 it was retired, Britten-Norman acquiring the fleet for conversion to civil sale. Outside the United Kingdom the Defender 4000 served with the Irish Garda air support unit between 1997 and 2023 and remains with the Police Service of Northern Ireland.