How do I follow ATC vectors and altitudes under IFR?

Under IFR, follow ATC vectors by reading back the assigned turn, heading and altitude, setting the heading bug and altitude selector, then executing and monitoring the manoeuvre. Hold the commanded heading—not a wind-corrected track—and remain at the cleared altitude until ATC replaces the clearance or expressly authorises a procedure.

For Aviation & Real-World Flying, that distinction is fundamental: a radar vector controls your heading, while a separate clearance controls your altitude. ATC may change either several times to sequence traffic, avoid weather or position you for an approach.

What does an ATC vector tell you to do?

An ATC vector tells you to fly a specified aircraft heading, normally magnetic unless local procedures use true headings.

For turn right heading 240, turn in the stated direction until the heading indicator reads 240°, then hold that heading. Do not steer a GPS ground track of 240° or correct for wind yourself. ATC observes the resulting radar track and supplies another heading when correction is needed.

Likewise, do not return to the magenta flight-plan line simply because a vector takes you away from it. Continue the assigned heading until ATC gives another vector, clears you direct to a fix, tells you to resume own navigation, or authorises you to intercept and follow a course.

• Fly heading 240 means maintain a heading using the heading indicator.
• Direct ABC means navigate from your position to the named fix.
• Intercept the localiser authorises lateral interception of that course, subject to the rest of the clearance.
• Resume own navigation returns lateral navigation to the cleared route or procedure.

Radar contact alone is not a vector, and a frequency hand-off does not cancel an assigned heading or altitude.

How should I action a heading and altitude instruction?

Use a listen, read back, set, execute and monitor flow whenever ATC combines a vector with a climb or descent.

1. Capture the full instruction. A note such as R240 / 3000 records turn right heading 240, descend and maintain 3,000. Ask ATC to repeat any uncertain number.
2. Read back the critical items. Include the turn direction, heading, altitude and callsign. Mandatory readback rules vary by jurisdiction, but headings and altitudes should always be read back clearly.
3. Set the controls. Put the heading bug on 240 and the altitude selector on 3,000. Cross-check both displays before relying on the autopilot.
4. Execute promptly. Start the turn and climb or descent without an unnecessary delay. Do not let programming or switch selection distract from flying the aircraft.
5. Monitor the result. Check the turn direction, flight mode annunciator, vertical rate, airspeed trend and altitude capture. Reduce an excessive vertical rate early enough to avoid overshooting the cleared level.

A mistake we see constantly in simulators is selecting the new altitude without engaging a vertical mode. The altitude selector usually provides a target or capture limit; changing the number alone does not make the aircraft climb or descend.

How should the ATC communications and readback sound?

A concise exchange leaves little room for a wrong heading or altitude:

ATC: G-ABCD, turn right heading 240, descend and maintain 3,000.

Pilot: Right heading 240, descend and maintain 3,000, G-ABCD.

If only part of the transmission was clear, do not guess. Use plain language such as say again heading, confirm three thousand or unable descent due terrain. An incorrect readback should be corrected by ATC, but the pilot must still question a clearance that appears unsafe or inconsistent.

Which autopilot modes follow ATC vectors and altitudes?

Use heading select for radar vectors and an appropriate vertical mode for the assigned altitude, while treating the flight mode annunciator as the final indication of what the aircraft will actually do.

Mode names and capture logic differ between aircraft. VS holds a vertical rate and can produce an unsafe airspeed if power and pitch are not monitored. An indicated-airspeed or flight-level-change mode protects the selected speed through pitch, but it still needs suitable power.

Some autopilots choose the shortest turn after a large heading-bug movement and may not respect ATC's spoken turn direction. Check the initial bank immediately; hand-fly or use the aircraft's appropriate heading-selection technique if it turns the wrong way.

Is the airspeed trend vector an ATC vector?

An airspeed trend vector is a flight-display prediction, not a radar heading from ATC.

Its direction and length indicate where the airspeed is likely to move over a short interval if the present acceleration continues. The exact prediction interval and display style depend on the aircraft. Use it to catch an approaching stall, overspeed or missed assigned speed, but do not steer it like a heading vector.

If ATC separately assigns an airspeed, read that speed back and monitor the trend while complying. Report unable if the requested speed conflicts with aircraft limitations or safe configuration.

What does “maintain 3,000” mean under IFR?

Maintain 3,000 means level at the assigned altitude of 3,000 feet and remain there until ATC issues another clearance or an authorised procedure permits departure from it.

There is no universal “IFR 3,000” rule making that altitude automatically valid everywhere. It may be an assigned departure, arrival or approach altitude, but terrain, airspace, minimum-altitude requirements and local procedures still matter.

• Descend and maintain 3,000 authorises a prompt descent followed by level flight at 3,000.
• Expect 3,000 is planning information, not permission to descend.
• Cross FIX at or above 3,000 sets a restriction at the fix; it does not necessarily require level flight at exactly 3,000.
• Maintain 3,000 until established requires you to stay at 3,000 until established on the authorised approach segment and otherwise cleared to descend.
• Descend via normally invokes the published arrival restrictions except where the clearance modifies them; exact phraseology and responsibilities vary by jurisdiction.

Below the applicable transition altitude, fly an assigned altitude using the correct local pressure setting. At a flight level, use standard pressure. An altitude of 3,000 feet and FL030 are not interchangeable, and low transition levels are used only in some regions.

Published restrictions remain significant when ATC assigns a SID or STAR. Our guide to applying SID and STAR altitude and speed restrictions explains when the procedure remains active and when an amended clearance takes precedence.

When can I leave an assigned heading or altitude?

Leave an assigned heading or altitude only when ATC replaces it, the clearance expressly activates an authorised procedure, or immediate safety requires a deviation.

• Remain on a vector until given another heading, cleared direct, told to resume own navigation, or authorised to intercept and follow a course.
• Remain at the cleared altitude until assigned another altitude or permitted to climb or descend through a procedure.
• Do not act on an altitude containing expect as though it were a clearance.
• Do not switch from heading mode to navigation mode merely because the flight-plan line is nearby.
• Do not descend because a glideslope indicator becomes active unless the approach clearance and altitude conditions permit it.

If wording is ambiguous, maintain the last unambiguous clearance and ask for confirmation. An ATC instruction and the autopilot setting are separate: entering a new heading or altitude does not itself grant permission to fly it.

What if I will cross the ILS localiser but have not been cleared for the approach?

Query ATC immediately and continue the assigned vector; do not turn onto the localiser solely because it is becoming clear that you will pass through it.

A controller's statement that you are being vectored for an ILS describes the intended sequence, not by itself an approach clearance. A suitable call is approaching the localiser, confirm intercept or request approach clearance.

• Only a heading was assigned: maintain that heading while querying ATC. Do not arm a mode that will capture the localiser and turn the aircraft without authorisation.
• ATC said to intercept the localiser: intercept and track it laterally, but maintain the last assigned altitude unless a separate descent or approach clearance permits descent.
• ATC cleared the ILS and said maintain 3,000 until established: hold 3,000 until established as required, then follow the authorised published profile and remaining restrictions.

If you pass through the localiser because the clearance arrived late, report it and await another vector. Do not make an unapproved reversal back towards the course. For the next stage, our detailed explanation of transitioning from ATC vectors onto a charted instrument approach covers localiser capture, vertical guidance and missed-approach preparation.

How can I get ATC vectors to final?

Request vectors to the named approach or runway before reaching the terminal area, provided radar service and controller workload allow it.

A plain request such as request vectors ILS runway 27 is sufficient. ATC may instead clear you direct to a fix or onto a published arrival, particularly outside radar coverage or when vectors are unavailable. Our guide to requesting radar vectors and understanding what they authorise gives the fuller radio sequence.

With built-in simulator ATC, vectors may depend on filing an IFR flight plan, accepting the assigned approach and using the available ATC menu option. Not every simulator or ATC implementation accepts free-form requests, so you may need to select the nearest offered request rather than transmit custom wording.

What should I do with an unclear, impossible or unsafe ATC instruction?

Maintain aircraft control, reject the unsafe element and tell ATC what you cannot accept.

Use unable, state the reason briefly and request an alternative heading, altitude or approach. The pilot in command remains responsible for terrain, weather, aircraft limitations and collision avoidance; an ATC clearance is never a reason to continue an obviously unsafe manoeuvre.

Built-in simulator ATC can produce late descents, unsuitable intercept angles or altitudes that conflict with terrain and charted procedures. Follow the last safe clearance, go around if the approach cannot be stabilised, and use our troubleshooting steps for wrong MSFS vectors, altitudes and runway assignments when the problem is repeatable.

For a real radio failure, apply the published lost-communications procedure for the jurisdiction, flight phase and clearance involved. Those rules are not interchangeable between countries and should not be replaced by a generic simulator technique.