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. The helicopter can considerably increase combat mission efficiency of Navy ships, Army aviation and tank detachments by providing them with timely information about the actions of the ships, fixed-wing aircraft and combat helicopters of the enemy.

Ka-31 helicopter is developed on the basis of Ka-27 ship-borne coaxial helicopter. 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. The search and attack equipment of Ka-27 helicopter intended for fighting against sub-marines is dismounted. Instead, 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. Ka-31 is based on the ships and on the ground.

The core of the on-board avionics suite is powerful 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.