How do ATC radar vectors work during departure and approach?
Learn how ATC radar vectors guide departures and approaches, what heading clearances mean, when to descend, and how to avoid common simulator errors.
In aviation and flight simulation, ATC radar vectors are heading instructions used to separate departing traffic, join an aircraft to its cleared route, sequence arrivals or line up an approach. The pilot flies each assigned heading and altitude until ATC changes the clearance, while monitoring terrain, weather and aircraft limits.
What exactly is an ATC radar vector?
A radar vector is an ATC-assigned heading rather than a route leg or commanded ground track. The term remains in common use even when the controller is observing aircraft through a mixture of radar, ADS-B and other surveillance systems.
Assigned headings are normally magnetic unless ATC identifies them as true. If told turn left heading 240, turn promptly in the stated direction and hold 240 degrees; do not apply your own wind correction to make the ground track equal 240. The controller observes the resulting track and issues another heading if necessary.
Clearance, departure, area and approach controllers may each issue vectors before handing the aircraft to the next frequency. Our guide to how the main ATC units divide responsibility for a flight explains those hand-offs.
How do departure radar vectors work?
Departure vectors take an aircraft from the runway environment towards its filed route while ATC provides traffic separation and an orderly flow from the airport.
- Read the initial clearance carefully. A SID may contain the first heading, or ATC may add an instruction such as
after departure, fly heading 180. Do not turn early or substitute the route shown by the flight management system. - Fly the assigned heading. Once the instruction becomes effective, set the heading bug and use heading-select mode or hand-fly that heading. Check the flight mode annunciation rather than assuming the autopilot accepted the selection.
- Maintain the cleared altitude. A heading change is a lateral instruction; it does not by itself authorise a climb through the last assigned altitude.
- Expect additional vectors or a direct clearance. Departure may alter the heading several times for traffic, then clear the aircraft directly to a fix or instruct it to resume its own navigation.
- Rejoin the route only when cleared. A magenta line passing beneath the aircraft is not permission to turn onto it.
A vector can replace part of a published departure without cancelling every other part of the clearance. The last explicit altitude and speed instructions remain controlling. Treatment of published constraints attached to fixes no longer being flown can vary with the clearance wording and local rules, so query ATC if there is any ambiguity. See our explanation of how published SIDs and STARs fit around ATC instructions for the wider route structure.
Runway heading also needs care. It refers to the runway centreline direction under the applicable local procedure and is not necessarily just the painted runway number multiplied by ten. Different authorities may define whether wind correction is expected, so follow the published procedure and local phraseology rather than guessing.
How do approach radar vectors work?
Approach vectors position and sequence arriving aircraft before intercepting an instrument final approach course or receiving a visual approach clearance.
- Leave the arrival when instructed. Approach may take the aircraft off its STAR with a heading, altitude and sometimes a speed restriction.
- Fly each vector without anticipating the next one. The sequence often resembles downwind, base and final, but traffic or airspace may produce a less obvious path.
- Prepare the assigned approach. Load and verify the runway, navigation source, frequencies and approach minima without allowing the FMS to turn the aircraft away from its assigned heading.
- Intercept only when authorised. ATC normally provides a suitable final vector and an approach clearance. The intercept should be shallow enough for the aircraft to capture the final course reliably.
- Descend only when cleared and permitted. Maintain the assigned altitude until the approach clearance and any restriction such as
maintain 3,000 until establishedallow descent.
A typical transmission is turn left heading 240, maintain 3,000 until established, cleared ILS runway 27 approach. Turn left to 240, remain at 3,000 feet until established on the localiser, then follow the authorised published vertical profile. Merely seeing localiser movement or arming approach mode is not permission to descend.
After receiving the clearance, monitor actual mode capture rather than just the buttons selected. Our mode-by-mode Boeing 737 ILS intercept procedure covers localiser and glideslope capture in detail.
Vectors-to-final may bypass intermediate fixes that the FMS expected to sequence. Activate the correct approach leg or intercept function for the aircraft; do not select direct-to the runway merely to remove a discontinuity. For non-ILS procedures, see how to handle vectors-to-final during an RNP approach.
What do common vectoring instructions mean?
| ATC instruction | Pilot action |
|---|---|
Turn right heading 090 | Turn right promptly and maintain a magnetic heading of 090 degrees. |
Fly present heading | Hold the heading being flown when the instruction is received. |
Direct ABC | Radar vectoring ends for that segment; use the aircraft's navigation system to fly directly to the named fix. |
Intercept the localiser | Continue the assigned geometry and capture the localiser, but do not descend without the required clearance. |
Resume own navigation | Stop following vectors and navigate along the cleared route, normally from a fix or route segment identified by ATC. |
Cleared approach | Fly the specified approach while observing any altitude, intercept or reporting restrictions included in the clearance. |
Can a pilot refuse an ATC radar vector?
A pilot can and should reject or question a vector that cannot be flown safely. Use unable, give the reason briefly and request an alternative heading, altitude or delay.
When vectoring an IFR aircraft, ATC normally applies the separation and obstacle-clearance requirements of that jurisdiction. An assigned altitude can legitimately be below a broad charted sector altitude because controllers may use more detailed minimum vectoring altitudes that are not printed on the pilot's approach chart. The pilot in command still retains final responsibility and must report concerns involving terrain, weather, fuel or aircraft performance.
VFR pilots remain responsible for terrain, cloud clearance and continued operation under visual flight rules. A radar vector does not convert a VFR clearance into an IFR one.
What if ATC stops issuing vectors?
If communication is working, maintain the last assigned heading and altitude and ask for further instructions. A concise call such as Approach, ABC123, heading 180 at 3,000, request further vectors tells the controller exactly what the aircraft is doing.
Do not turn towards the airport, intercept final or descend on your own simply because the next instruction seems late. If the aircraft is about to cross the final approach course without a clearance, query ATC immediately; the controller may intend to take it through final for spacing.
Built-in simulator ATC can occasionally issue late intercepts, leave an aircraft on a stale heading or vector it into poor terrain geometry. Keep monitoring the chart and aircraft position. If an instruction is unsafe or impossible, refuse it just as a real pilot would rather than chasing the autopilot into an unstable approach.
For an actual communications failure, follow the published lost-communications procedure for the jurisdiction and the clearance already received. Those rules are not replaced by a guessed turn towards the destination.