The Indian Air Force (IAF) is set to equip its fleet of Sukhoi Su-30MKI multirole fighters with the Rafael Advanced Defense Systems I-Derby ER (extended range) beyond-visual-range air-to-air missile (BVRAAM) once the service phases out its ageing Russian-made Vympel R-77 (AA-12 ‘Adder’) AAMs by 2021-22. An earlier version of the Rafael Derby, which can be configured as a surface-to-air missile, is also part of the IAF’s 18 Spyder-SR air-defence systems acquired from Rafael in 2008-09 for an estimated USD1 billion. Delivery of the Spyder-SR systems, which included 750 Derby missiles, began in 2012 and was completed three years later.
The Rafael Derby also known as the Alto, is a beyond-visual-range air-to-air missile (BVRAAM). Though technically not part of the “Python” family, the missile is an enlarged version of the Python-4 with an active-radar seeker. In June 2015, Rafael confirmed the existence of the I-Derby-ER, an extended range version of the Derby that increases range to 54 nmi (62 mi; 100 km), after a “Python 6” version based on an air-launched Stunner missile was abandoned. To achieve greater range, a dual-pulse solid rocket motor is added, where the secondary pulse of energy as the missile nears the target extends flight time. It also combines the seeker and fuse into an integrated sensor and fusing system to make room for the new motor.
The Indian Air Force is in talks with Rafael to acquire the active radar-guided I-Derby ER BVRAAM, which has a range of 100 km, adding that the procurement process for the missiles could be finalised “imminently”. The latest developments come after the fire-and-forget I-Derby ER missile, which features a software-defined radar seeker and a dual-pulse solid rocket motor, was selected to be the primary AAM to arm the Indian Air Force’s indigenously designed HAL Tejas Light Combat Aircraft (LCA) fighter following successful test-firings in July 2018.