The Kamov Ka-31 (NATO reporting name Helix) is a military helicopter originally developed for the Soviet Navy and currently in service in Russia, China, and India in the naval airborne early warning and control role.

As with all Kamov helicopters except the Ka-60/-62 family, the Ka-31 has co-axially mounted contra-rotating main rotors.

One visually distinctive feature of the Ka-31 is the large antenna of the early-warning radar, which is either rotating or folded and stowed under the fuselage.

The Kamov design bureau was asked by the Soviet Navy to begin the development of an early-warning helicopter in 1985.

The Ka-31 is equipped with the E-801 Oko L-band radar, capable of detecting and tracking up to 40 targets simultaneously, flying from 5 to 3,500 meters altitude.

Due to its relatively small size, the Ka-31 doesn't have the capability to process the information collected by its radar.

[1] In May 2022, the Indian government indefinitely suspended the negotiations with Rosoboronexport due to concerns over Moscow’s ability to execute orders and issues related to payment transfers.

The operation with the Indian Navy revealed a major drawback of the aircraft, its limited endurance/range, the chief element of a taskforce/battlegroup.

In response, Hindustan Aeronautics Limited was commissioned to experiment and possibly adapt a helicopter-to-helicopter refuelling system.

[7] In 2008, China ordered nine Ka-31s to equip the People's Liberation Army Navy's carriers.