Later variants of the Ka-27 include the Ka-31 airborne early warning helicopter equipped with the E801M Oko (Eye) air and sea surveillance radar
The Ka-31 helicopter is intended for long-range detection of air targets of a fixed-wing/helicopter type, including detection at low altitudes, and over-waters ships, their tracking and automatic transmission of their data to the command posts.
Under the transport cabin floor there is a compartment housing the support-rotating mechanism of a 6-m span antenna. To prevent the interference in the antenna all-round rotation plane the nose landing gear legs are retracted rearward into the cowlings flight-wise and the main legs are retracted upward. In stowed position the antenna is kept against the fuselage bottom. A radio-electronic suite is installed for radar target detection, targets identification and transmission of the over-water and air situation data to the ship-based and ground-based command posts. The core of the on-board avionics suite is the solid-state radar. The radio-electronic package automatically controls the helicopter flight over the specified route in any weather and climatic conditions. When the radio-electronic package is on, the antenna is extended and the navigator has elected the operational mode, all further operations are performed automatically without operator interference. The navigator role is simply to control the systems operation and to duplicate target observation on the display screen.
Power is from two Klimov TV3-117VMA turboshafts, each 1,633kW, and started by APU. The fuel tanks are filled with reticulated polyurethane foam for fire suppression.
The Ka-31 (formerly Ka-29RLD: radiolokatsyonnogo Dozora: radar picket helicopter) development began in 1980 and was first flown in October 1987. Two examples (031 and 032) completed initial shipboard trials on the Admiral of the Fleet Kuznetsov (then Tbilisi) in 1990, state testing being completed in 1996.
Following a 1996 evaluation, four Ka-31s were ordered in August 1999 by the Indian Navy for delivery in 2001 and basing aboard the the aircraft carriers and 'Krivak' class destroyers. A further five were ordered in February 2001. Limited production of the Ka-31 was launched (for Indian Navy) at Kumertau Aircraft Plant, Bashkiriya, in 1999. The Indian aircraft have 12-channel Kronshtadt GPS with Abris digital moving map and a 152x203mm AMLCD screen.
First flight of an Indian Ka-31 was on 16 May 2001, and by October 2001, the first two Indian airframes were delivered from KAPP to Kamov at Moscow for avionics installation. Flight trials were completed of the first two Indian aircraft by September 2002. The Indian Navy batch of was four priced at Rs4 billion (US$92 million) (2000), and the second five cost US$108 million (2001).
In October 2002, Kamov reported a second export customer for Ka-31s in addition to Indian Navy.
Rotor diameter: 15.90m
Fuselage length: 11.30m
Max take-off weight: 12500kg
Max speed: 255km/h
Cruising speed: 220km/h
Hovering ceiling: 3700m
Range with max fuel: 680km