In 1958 increasing concern over the threat of an American nuclear strike against the USSR from the north led to a new requirement for an airborne radar system, which would avoid the problems and expense of attempting to create a land-based radar system to cover all of the enormous Soviet northern coast.

To adhere to the flight range requirements, the plane was fitted with an air-to-air refuelling probe.

The Tu-126 had a crew of 12 and carried the Liana radar (NATO reporting name Flap Jack) in a rotodome mounted above the fuselage.

It had no look-down capability, so the switch by NATO to low level penetration made it fairly irrelevant.

[2] Testing, which continued through the autumn of 1964, showed that while the radar was effective over water, performance was poorer over land.