The Anglo-French fleet of the Sepecat Jaguar deep penetration strike aircraft of the Indian Air Force (IAF) is one of its primary strike aircraft in the combat fleet. Out of the fleet of 140 aircraft acquired initially, currently around 125 remain in service. Inducted into the IAF some four decades back, it has undergone multiple upgrades in its avionics and weapons, keeping it relevant in its role for the IAF. However, the most important component of the aircraft, its engine, is yet to undergo upgradation.

The aircraft, powered by two Rolls-Royce’s Adour Mk 811 turbofan engines, is underpowered and hence to improve its flight envelop which could allow it to operate in high operating environment such as in the mountains, a more powerful engine is required.

Since, its induction into the IAF, the aircraft has seen upgradation of its avionics, radar systems and integration of laser guided and other modern weapons systems; but the need for new and significantly more powerful engines has remained unfulfilled.

The Jaguar fleet has completed more than 30 years of service with the IAF. It has no specified airframe calendar life and is only based on Fatigue Index. Based on the individual aircraft operational exploitation the fleet, it is believed that it has an approximate residual 15-20 years of airframe life. Modernization will add additional operational life to the aircraft for another 20 years. The decision to replace the engines must be made immediately. Any further delay in purchasing the engines will be useless.

The IAF is losing its fleet strength rapidly, but it has not been able to acquire replacement aircraft, except for the Russian Su-30 MKI which has been joining its fleets regularly. Had it not been for the Su-30 MKI, the IAF would have lost its fleet strength as well as superior strike capability vis-à-vis its adversary. In the last two decades, instead of acquiring new combat aircraft, thanks to cumbersome acquisition process and budgetary shortages, the IAF has been forced to upgrade its legacy aircrafts including the Jaguar fleet.

Upgrade by HAL

HAL-built Jaguar’s are fitted with the more advanced Display Attack and Ranging Inertial Navigation (DARIN) avionics suites. These include Head-UP Display, a GEC-Ferranti Combined Map & Electronic Display (COMED) 2045, a SAGEM ULISS 82 Inertial Navigation System and a Laser Ranger and Marked Target Seeker. The system also includes a locallydesigned Identification Friend/Foe, Automatic Direction Finder, radar altimeter, U/VHF R/T sets and HF/SSB equipment. The maritime-attack Jaguar IM initially sported nose mounted Agave radar with display facility in either the Head-UP Display or the COMED. Capable of air-to-air operations as well, the Agave was optimised for maritime air-to-surface operations. Original Agave radar on 20 maritime strike role Jaguar’s has been replaced by multirole ELTA EL/M-2032 (Not AESA) radar about 10 years back.

Honeywell F125N engine

Currently, HAL is integrating the Jaguar’s with DARIN III systems. The upgrade incorporates new state-of-the-art avionics architecture including the Open System Architecture Mission Computer (OSAMC), Engine & Flight Instrument System (EFIS), Fire Control Radar, State-of-the-Art Inertial Navigation System with GPS and Geodetic height correction, Solid State Digital Video Recording System (SSDVRS), Solid State Flight Data Recorder (SSFDR), Smart Multi-Function Display (SMD), Radio Altimeter with 20000 ft range, Autopilot with Alt Select & HNAV and Identification of Friend or Foe (IFF).

HAL is also integrating the Active Electronically Scanned Array (AESA) radar from Israel into the DARIN III aircraft. India has ordered 58 of these radars from ELTA, Israel. The first flight of the Jaguar with EL/M-2052 AESA radar was conducted in August, last year. These aircraft will also have smart CBU-105 Sensor Fuzed weapons.

Re-Engining

On November 26, 2010, Ministry of Defence (MoD) issued a Request for Proposal (RFP) to two of the leading engine manufacturers, Rolls-Royce the original power plant provider and to the American engine manufacturer Honeywell for its F125IN. In response to the tender, Rolls-Royce initially offered the Adour Mk 821, an upgraded version of the existing engine Adour Mk 811, which delivers higher thrust. But this is not actually a new engine, but offered certain advantages such as proven technology and commonality with existing engine and also with the Adour Mk 871 turbofan fitted on the IAF’s advanced jet trainer Hawk Mk132.

The Jaguar have completed more than 30 years of service with IAF and most of the fleet does not have more than 15 years of airframe life

As reported earlier by SP’s Aviation, when compared with the engine currently fitted on the Jaguar, the F125IN turbofan from Honeywell delivers 30 percent higher thrust. Honeywell claims that the F125IN would offer a 9850lbf (43.8kN) thrust engine that will deliver high performance, “improved pilot safety, lower maintenance costs and outstanding reliability”. Honeywell also claimed that the modular construction of the F125IN and its integral dual full authority digital engine control (FADEC) system would provide substantial savings to the operator in life-cycle costs. The engine is projected to save the Indian Air Force more than 7,000 crore in life-cycle costs compared to other upgrade options being considered. The F125IN permits the Jaguar to perform missions never before possible with the current engine.

It is however not clear whether or to what extent an ageing airframe will be able to fully and gainfully exploit the significantly higher level of thrust the two F125IN engines are capable of delivering. The improved thrust to weight ratio and maneuverability will surely increase the fatigue index counters.

The F125IN fitted on a Jaguar was successfully demonstrated to the IAF in 2007. Honeywell has moved forward since then acquiring its own Jaguar airframe and has completed design of its standard engines for production and is now ready for flight demonstration. Rolls-Royce opted to withdraw from the contest rather than be eliminated, resulting in a “single vendor situation”. Now, as dictated by the provisions of the Defence Procurement Procedure (DPP), the MoD has been compelled to withdraw the RFP.

The 120 twin-engine Jaguar’s will get new engines supplied by Honeywell, for an estimated $3 billion. Each Honeywell F125N engine delivers 43.8 KiloNewtons (kN) of thrust, significantly higher than the 32.5 kN of the Jaguar’s current Rolls-Royce engine. If this proposal of the Honeywell gets government approval, then the aircraft’s range will go beyond 400 km and will also enable it to fly across the mountains with a higher rate of climb.

In the meantime, HAL, which has been upgrading the aircraft, reportedly, is also interested in doing the re-engining. They proposed to integrate the F125IN engines into the fighters with Honeywell as a consultant to the project. The F125IN Engine, based on off-the-shelf, in-service F125 engine, is expected to reduce the take-off distance of the Jaguar by over 30 percent and enhance mission capability above 30,000 feet. This engine is also expected to reduce the life cycle cost of the aircraft. In line with the ‘Make in India’ programme, Honeywell has planned to get 25 per cent of the engine components manufactured in India. They also intend to do all airframe modification, testing and certification in India.

In the meantime, as the spares production lines are getting closed, India is procuring 31 decommissioned Jaguar’s from France for spares to keep the existing fleet flying.