Sector 4 is one of the all-level southern Stockholm sectors, the other being Sector 3. It covers a large area south of Stockholm, below FL285, and operates on 118.2 MHz. The northern part of Sector 4 is an all level area with no upper limit.

The main tasks of sector 4 are:

• En-route traffic transiting East-West and vice-versa
• Descend and arrival instructions for Stockholm arrivals via XILAN, HMR VOR
• Climb for Stockholm departures via BABAP, RESNA and Nortel VOR NTL

The all level part of Sector 4, above Stockholm TMA, means that the sector will handle some en-route traffic, mainly heading westbound from Helsinki to Oslo. Apart from this, the main focus of Sector 2 should be traffic to and from Stockholm TMA from the north and east, which will require some work in order to establish orderly traffic flows both to and from the TMA.

Sector 4 is usually combined with Sector 3, and can also be combined with Sector 2 to the south.