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Vectoring Fundamentals

Identify before vectoring

No vectoring starts without identification. Before providing the ATS surveillance service, the controller must establish the identification of the aircraft and inform the pilot. That identification must be maintained until the end of the service1. If it is lost, the pilot must also be informed2.

The most common methods with secondary surveillance radar (SSR) and ADS-B are3:

Method How to do it
Identification on the tag The tag shows the aircraft's callsign, or a discrete code that has already been verified.
Code change Assign a code to the pilot and watch the change on the screen.
IDENT activation Request IDENT and watch the response. The function should only be activated at the controller's request.
Identification transfer The previous controller hands over the aircraft already identified.

A discrete code can only be used as the basis for identification after it has been verified: confirm that the code selected by the pilot is the one assigned4. On the network, this means confirming that the tag is correlated with the right flight plan, not just that there is a tag on the screen.

When two targets are very close together or are making similar movements, use more than one method until any doubt is removed5.

Informing the position

When you identify the aircraft, inform its position. The exceptions are identifications made by transfer, by the pilot's own position report, by a departure observed within 1 NM of the end of the runway, or by the Mode S, ADS-B or discrete code tag, when the position on the screen is consistent with the flight plan6. The position may be given in relation to a well-known point, by bearing and distance from a navigation aid or fix, or as the distance from touchdown when the aircraft is on final7.

TAM 3501, radar contact, 40 miles South of Brasília, descend to FL 070, expect ILS Z approach runway 29L.

While the ATS surveillance service is being provided, the pilot is exempt from reporting position at compulsory reporting points and only reports where ATC requests8.

What vectoring is

Vectoring means giving the aircraft headings and levels instead of the route it would fly on its own. The ATM Glossary defines vectoring as the "provision of navigational guidance to aircraft in the form of specific headings, based on the use of an ATS surveillance system"37.

A direct is not vectoring

"Cleared direct LOMEN" is not a heading: the pilot navigates on their own to the fix. A direct is therefore not vectoring, even when it takes the aircraft off the published track of a STAR. MCA 100-16 treats the two cases separately, as "vectoring or direct flight"38. The difference changes who is responsible for obstacle clearance. See What about a direct?.

ICA 100-37 is direct about what vectoring implies9:

Under vectoring, navigation is yours

"Whenever an aircraft is under vectoring, the Air Traffic Control Service shall be provided and the controller shall be responsible for the navigation of the aircraft, transmitting to it the heading instructions and level changes that become necessary."

The most serious consequence concerns obstacle clearance. Outside vectoring, the Air Traffic Control Service does not include the prevention of collision with the ground, and the pilot must check that the clearance is safe in that respect. Under vectoring, that check is no longer the pilot's10. A vectored pilot may not even know the exact position of the aircraft and therefore cannot verify the safe altitude. It is up to the controller to issue clearances that ensure obstacle clearance at all times, until the point where the pilot resumes own navigation11.

When to vector

Vectoring serves six purposes12:

  1. to establish separation;
  2. to guide the aircraft in carrying out special procedures;
  3. to obtain an operational advantage for ATC or for the aircraft, such as a more efficient sequence or a shorter track;
  4. to steer the aircraft around weather or wake turbulence;
  5. to correct significant route deviations;
  6. to meet a pilot's request, when possible.

Vectoring for its own sake is not one of them. Whenever the published route (SID, STAR, airway) solves the problem, prefer it. The workload is lower for both sides, and a communication failure does not leave the aircraft without a heading to fly.

Minimum vectoring altitude

Since obstacle clearance becomes yours, every heading must come with a safe altitude for the area the aircraft will overfly. ICA 100-37 requires the controller to always have complete and up-to-date information on the minimum flight altitudes in the area, the lowest usable levels and the minimum altitudes of procedures based on vectoring13.

In TMAs that have the chart, this information is on the ATCSMAC (ATC Surveillance Minimum Altitude Chart), published by DECEA on AISWEB. It divides the TMA into sectors, each with its minimum vectoring altitude. Where there is no ATCSMAC, use the most conservative reference among the MSA on the IAC and the minimum altitudes on the en-route and area charts.

Below the MSA, only with the right chart

The MSA on the IAC is a safe altitude within 25 NM of the navigation aid. It is not the minimum vectoring altitude. Vectoring below the MSA is only safe with the ATCSMAC (or equivalent) at hand. Without it, keep the aircraft at or above the MSA until it is established on a published procedure.

When the pilot asks to deviate around weather below the published minimum safe altitude, responsibility for obstacle clearance goes back to the pilot. The phraseology makes this explicit: the controller informs the minimum altitude and approves the deviation14.

What about a direct?

For a direct given to an aircraft on its own navigation, the vectoring rule does not apply in the strict sense:

  • The pilot remains responsible for terrain. Outside vectoring, it is up to the pilot to ensure that the clearance is safe with respect to the ground10. An IFR flight keeps the minimum level of the route and, off route, flies at least 1,000 ft (2,000 ft over mountainous terrain) above the highest obstacle within 8 km. Calculating that level is the pilot's job39.
  • The controller does not clear below the published minimum. The altitudes of a STAR protect only the published segments. On the direct leg, the reference is the minimum altitude for the area: the MSA or TAA of the IAC, the AMA or the ATCSMAC40. The controller must have these altitudes at hand13 and cannot issue a clearance below them41.
  • Under vectoring, a direct is still vectoring. If the aircraft is already being vectored and is given a direct track that takes it off the ATS route, obstacle clearance remains with the controller until the point where the pilot resumes own navigation11. That is why the phraseology ends vectoring with "resume own navigation, cleared direct…".

In practice

For a direct from own navigation, clear a level at or above the MSA (or TAA/AMA) of the segment. To clear below the MSA, use the ATCSMAC, which is published for use with surveillance. This is a combined reading of the rules cited: none of them says, literally, that a direct requires the ATCSMAC.

Start, limits and termination

Start

The start of vectoring is marked by the controller informing that the aircraft is under vectoring15. If the first vector takes the aircraft off an established route, also inform the purpose of the vector. When the heading given could create a hazard if communication is lost, also specify the limit of the vector16.

TAM 3205, vectoring for ILS final approach runway 29L, turn left heading 240.

TAM 3456, vectoring for sequencing, turn left heading 285, limit three minutes to resume own navigation direct NIMTO.

Methods

There are six ways to give a vector17:

Method Example
Direction of turn and final heading "turn right heading 070"
Heading to fly "fly heading 150"
Maintain the current heading "maintain present heading"
Direction and number of degrees, when the aircraft's heading is not known and there is no time to obtain it "turn 30 degrees left"
Heading to leave a navigation aid the aircraft is over "leave BUENO heading 240"
Start and stop of turn, when the aircraft's heading instruments are unreliable "turn right... stop turn"

With the number-of-degrees method, before the manoeuvres ask the pilot to make all turns at rate one and to comply with the instructions immediately on receipt17.

Geographical limits

  • Except during a transfer of control, do not vector within 2.5 NM of the boundary of your airspace. If the applicable separation minimum is greater than 5 NM, the minimum distance becomes half of that separation18.
  • Do not vector controlled flights outside controlled airspace, except in an emergency, to avoid weather (informing the pilot) or at the pilot's request19.
  • Whenever possible, vector along tracks on which the pilot can monitor their own position using navigation aids. This reduces the assistance needed and mitigates a possible failure of the surveillance system20.

During vectoring

While the aircraft is under vectoring, you must21:

  1. assign an altitude to maintain, respecting all restrictions;
  2. bring the aircraft back into controlled airspace compatible with its destination;
  3. give a heading that intercepts the desired radial or track at a distance that ensures the interception;
  4. give advance notice if, for any reason, the aircraft must leave radar coverage and the pilot has to resume navigation from a given point;
  5. keep the pilot informed of the aircraft's position.

Termination

When vectoring ends, instruct the pilot to resume own navigation. If the vectors have taken the aircraft away from the assigned route, also inform its position and give the necessary instructions22.

TAM 3702, 50 miles Southeast of Campo Grande VOR, resume own navigation, heading Urubupungá VOR.

On approach, there is no need to inform the termination of the ATS surveillance service when the aircraft makes a visual approach or is vectored to the final approach track23. Vectoring for an ILS ends when the aircraft intercepts the final approach course and the glide path24.

Separation with ATS surveillance

Minima

Situation Minimum Source
Horizontal separation with PSR, SSR, ADS-B or MLAT 5 NM 25
Only en-route radar available in the TMA or CTR 10 NM 25
Vertical separation applied by an APP 1,000 ft 26
Aircraft holding over the same fix The radar minimum does not apply: separate vertically 27

The distance is measured between the centers of the targets. Under no circumstances may the edges of the targets touch or overlap without vertical separation28. Radar minima only apply between identified aircraft whose identification is likely to be maintained29. A departure may be separated by radar from take-off, provided it is likely to be identified within 1 NM of the end of the runway30.

Reduced minima

A reduction below 5 NM is only permitted in accordance with a specific DECEA publication31, and in the real world it exists only in designated areas. On the network, apply 5 NM unless the TMA's MOP authorizes another value.

Levels on the screen

Based on pressure-altitude, an aircraft is considered to be32:

Situation Criterion (RVSM airspace)
Maintaining the level Within ±200 ft of the assigned level
Vacating the level Has moved more than 300 ft in the expected direction
Passing a level when climbing or descending Has gone more than 300 ft beyond it, in the expected direction
Reaching the cleared level Has been within ±200 ft for three updates or 15 seconds, whichever is greater

Outside RVSM airspace, the tolerance for maintaining and reaching is ±300 ft. The criteria for vacating and passing do not change.

An aircraft may only be cleared to a level occupied by another after the other has reported vacating it. In severe turbulence, only after it has reported being at the new level33.

Wake turbulence

In the approach and departure phases, and en route below FL 240, apply the wake turbulence minima when they are greater than 5 NM34:

Leading Following Minimum
SUPER (J) HEAVY (H) 6 NM
SUPER (J) MEDIUM (M) 7 NM
SUPER (J) LIGHT (L) 8 NM
HEAVY (H) HEAVY (H) 4 NM
HEAVY (H) MEDIUM (M) 5 NM
HEAVY (H) LIGHT (L) 6 NM
MEDIUM (M) LIGHT (L) 5 NM

These minima apply when the following aircraft is flying behind the leading one, or crossing behind it, at the same altitude or less than 1,000 ft below, and when both use the same runway or parallel runways less than 760 m apart35. The category of each type is in ICAO Doc 8643 and appears in the flight plan (A320/M, B77W/H, A388/J). SUPER and HEAVY aircraft must include "super" or "heavy" in the initial call36.

In practice

The minimum that applies is always the greater of the radar minimum and the wake turbulence minimum. A B77W followed by an A320 on final calls for 5 NM for wake turbulence. This matches the radar minimum, and even so there is no margin for compression. An A320 followed by a C172 calls for 5 NM for wake turbulence, and a B77W followed by a C172, 6 NM.

  1. ICA 100-37, Art. 906. See ICA 100-37. ↩

  2. ICA 100-37, Art. 907. ↩

  3. ICA 100-37, Arts. 909 and 910. ↩

  4. ICA 100-37, Art. 911. ↩

  5. ICA 100-37, Art. 914. ↩

  6. ICA 100-37, Art. 917, item I. ↩

  7. ICA 100-37, Art. 918. ↩

  8. ICA 100-37, Art. 920. ↩

  9. ICA 100-37, Art. 921. ↩

  10. ICA 100-37, Art. 93, sole paragraph. ↩↩

  11. ICA 100-37, Art. 922 and its § 2°. ↩↩

  12. ICA 100-37, Art. 924. ↩

  13. ICA 100-37, Art. 934. ↩↩

  14. MCA 100-16, Art. 117. See MCA 100-16. ↩

  15. ICA 100-37, Art. 923. ↩

  16. ICA 100-37, Art. 927. ↩

  17. ICA 100-37, Art. 925 and sole paragraph. ↩↩

  18. ICA 100-37, Art. 928. ↩

  19. ICA 100-37, Art. 929. ↩

  20. ICA 100-37, Art. 926. ↩

  21. ICA 100-37, Art. 930. ↩

  22. ICA 100-37, Art. 933. ↩

  23. ICA 100-37, Art. 940. ↩

  24. ICA 100-37, Art. 1008. ↩

  25. ICA 100-37, Art. 953 and its § 2°. ↩↩

  26. ICA 100-37, Art. 432. ↩

  27. ICA 100-37, Art. 952. ↩

  28. ICA 100-37, Arts. 948 and 949. ↩

  29. ICA 100-37, Art. 946. ↩

  30. ICA 100-37, Art. 951. ↩

  31. ICA 100-37, Art. 954. ↩

  32. ICA 100-37, Arts. 897 to 901. ↩

  33. ICA 100-37, Art. 433. ↩

  34. ICA 100-37, Arts. 956 and 959, Table 11. ↩

  35. ICA 100-37, Art. 960. ↩

  36. ICA 100-37, Arts. 206 and 208. ↩

  37. MCA 100-27, Glossário ATM, item 595. ICA 100-37 refers to this glossary for its definitions (Art. 9°). See MCA 100-27 (ATM Glossary). ↩

  38. MCA 100-16, Art. 115, items VI, VIII and IX. ↩

  39. ICA 100-12, Art. 137 and § 1°. See ICA 100-12 (Rules of the Air). ↩

  40. MCA 100-16, Art. 117, which lists AMA, MSA, TAA and ATCSMAC as published minimum safe altitudes. ↩

  41. ICA 100-37, Art. 302. ↩