Vikrant’s Rotary Sentinel: Ka-31AEW

On 28 March 2023 the maiden night landing of helicopters onboard INS Vikrant included Kamov Ka-31 Airborne Early Warning (AEW) helicopter of INAS 339 ‘Falcons’ flown by Test Pilot of Naval Flight Test Squadron from INS Hansa. Incidentally, the Indian Navy (IN) ordered four Ka-31 AEW helicopters in 1999 and a further five in 2001. The first batch entered service with the IN in April 2003, while the second batch was delivered in 2005. Another five entered service in 2013. INAS 339 'Falcons’ squadron operate the type, with a fleet of 14 helicopters based at INS Hansa in Goa. Further acquisitions have been temporarily put on hold. Optimised for AEW operations from major surface combatants of any size, Kamov JSC, based in Moscow, began development of the Ka-31 AEW naval helicopter in 1980 and the first flight took place in 1987. Powered by Klimov TV3-117VMAR turboshaft engines (rated at 1,633-kW each), the main mission of the helicopter is long-range detection of threats, including airborne threats such as fixed-wing aircraft and helicopters. Surveillance, target tracking and transmission of the target data to the command posts is carried out onboard the helicopter, thereby increasing the combat efficiency of associated naval units regarding interception of aerial threats plus Over-The- Horizon (OTH) strikes at hostile units. The airframe of the Kamov Ka-31, based on the proven and highly successful Kamov Ka-27, has co-axially mounted contrarotating main propellers. The original AEW version was Kamov Ka-29TB/Ka- 29RLD (Radiolokatsyonnogo Dozora). The distinctive antenna of the AEW radar either rotates while operational, or remains folded and stowed under the fuselage. The Ka-31 has a maximum take-off weight of 12,200 kg. The operating altitude is up to 3,500 m. The helicopter flies on patrol at 100 km/h and the operational range with the antennas in the stowed position is 600 km. The mission duration is two hours 30 minutes. A proposal to extend the endurance of the helicopters is being considered by Air-to-Air Refuelling (AAR).

The flight deck of the Ka-31 helicopter is wider than that of the Ka-27 and accommodates the pilot and the navigator in an armour protected cockpit. The navigation suite includes a Kronstadt Kabris 12 channel Global Positioning System (GPS), digital terrain mapping, groundproximity warning and obstacle approach warning. In IN service, the aircraft received Abris GPS system featuring a 12 channel receiver and option to employ Differential GPS references, designed by the Kronstad itself. The AEW radar, E-801M Oko (‘Eye’), was developed by the Nizhny Novgorod Radio Engineering Institute. The 6-m² radar antenna is stowed flat against the underside of the fuselage until deployed. The navigator switches on the radar system and the antenna extends, turning through 90° from the horizontal to the vertical plane. The landing gear retracts in order to prevent interference with the radar. In operation the antenna rotates at 6-rpm. Once the navigator has switched the radar system to operational mode, the system works autonomously without operator control. The navigator monitors the target observation on a display. The radar has 360° azimuthal coverage. The surveillance range against a fighter aircraft size target is up to 150-km. The surveillance range against a surface ship is typically 100 km to 200 km. The radar is capable of simultaneously tracking 40 targets. Target tracking data is transferred to the command post through datalink. Power for the radar and antenna is provided by an auxiliary power unit, type TA-8Ka, installed above the rear section of the engine bay. When the radar surveillance phase of the mission is completed the antenna is retracted to the storage position. The antenna is fitted with explosive bolts enabling it to be jettisoned quickly in an emergency, such as in preparation for a forced landing.

Sayan Majumdar

(Photos of IN Ka-31AEWs for reference only)