All aircraft do not have the same performance. Weight, weather and winds can make the same airplane have different performance on different flights.
As a controller, you should have knowledge about the performance of aircraft under normal circumstances in order to be able to plan traffic flow and give the pilots relevant instructions.
At the end of this section, you will find a table which lists the performance of the most usual aircrafts. Use this table as reference.
All aircraft generate turbulence called vortex wake. Large aircraft flying at slow speeds create the most severe wake turbulence. This turbulence can cause problems for following aircraft, which in severe cases can cause the pilot of the following aircraft to loose control. In addition to separation minimum above, the following spacing minima therefore needs to be taken into account. The wake turbulence categories are based on the certified maximum take-off weight (MTOW) of the aircraft.
|Light Aircraft (L)||7 000 kg|
|Medium Aircraft (M)||7 000 – 136 000 kg|
|Heavy Aircraft (H)||>136 000 kg|
This leads to the following minimum separation that needs to be maintained at all times on Arrival.
|Leading Aircraft||Following Aircraft||Separation in NM|
Vortex separation is required when a lighter aircraft follows a heavier aircraft.
No vortex separation is required between aircraft of same category, except between heavies.
If parallel runways are being used and they are closer to each other than 760 meters, then they should be considered as one single runway so far as wake turbulence is concerned.
Any aircraft performing a Touch and Go or a Stop and Go is considered a departing aircraft on the climb out phase.
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft.
Any Helicopter under your control must be kept clear of any light aircraft due to the Rotor Down-wash it produces when hovering and the vortices it produces in forward flight.
If you have a heavy and a light aircraft both ready for departure, you should clear the light aircraft for take-off first in order to avoid wake delay. However this only applies if it does not create any undue delay to the heavy aircraft. If this is the case, then the rule applies in that the faster aircraft is released first.
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it is a light or medium aircraft departing as follows:
A different way to differentiate categories is by their minimum Approach Speed. This is what the different Cat A, B, C, etc refers to on various Approach Charts.
|Aircraft Category||Approach Speed|
|A||Up to 90 kt|
|B||From 91 to 120 kt|
|C||From 121 to 140 kt|
|D||From 141 to 165 kt|
|E||Above 165 kt|
The pilot of an aircraft must have detailed knowledge about the aircraft's performances.
As ATCO it is hard to know all details about all aircrafts by heart. There are however, situations where you need to know some certain performances in order to issue correct clearance and instructions. Hence you need to know where to find the information.
One way is asking the pilot if (s)he is able to comply with a certain instruction, but that takes extra time and you cannot ask all pilots all the time.
There are several abbreviated listings of different aircraft and their performances on the Web. One of the most comprehensive and up to date is found on ICAOs homepage:
The list over performances should be seen as a guide and it deserves to be stressed that it is the pilot that has the last word when it comes to judging if (s)he is able to comply with a certain instruction.
These suffixes denote what navigation and transponder equipment is available for the aircraft, as filed in the flight plan by the pilot.
Be alert as to the equipment available on the aircraft and issue vectors accordingly. A list over the most common codes for equipment can be found at the end of this section.
|Cessna Citation X||35.300||31.800||3.300||FL510||.88M||.92||350|
|MTOW||Maximum Takeoff Weight|
|MLW||Maximum Landing Weight|
|Range||Maximum Operating Distance|
|Ceiling||Maximum Operating Altitude|
|Vr||Takeoff Rotation Speed at MTOW (KIAS)|
|Vcruise||Design Cruising Speed at Given Altitude (KTAS)|
|Vcruise Economy||Speed and Altitude for Bets Fuel Economy and Long Range (KTAS)|
|Mmo||Maximum Operating Spped (Redline in Mach)|
|Vmo||Maximum Operating Speed (Redline - Jet/Turboprop) (KIAS)|
|Vne||Nevner Exceed Speed (Redline - Recip-Prop) (KIAS)|
|Vref||Final Approach Speed at MLW in Landing Configuration (no wind)|
|Vsi||Stall Speed in MLW in Clean Configuration (Flaps Up) (KIAS)|
|Vso||Stall Speed in Knots IAS at MLW in Landing Configuration (KIAS)|
|No DME Equipment on board|
|/U||Transponder with Mode C|
|DME Equipment Available|
|/A||Transponder with Mode C|
|TACAN ONLY (usually Military Aircraft)|
|/N||Transponder with no Mode C|
|/P||Transponder with Mode C|
|AREA NAVIGATION (RNAV)|
|/Y||LORAN, VOR/DME, or INS with no Transponder|
|/I||LORAN, VOR/DME, or INS, Transponder with Mode C|
|ADVANCED RNAV WITH TRANSPONDER AND MODE C (If an aircraft is unable to operate with a transponder and/or Mode C, it will revert to the appropriate code listed above under Area Navigation)|
|/E||Flight Management System (FMS) with en route, terminal, and approach capability. Equipment requirements are:|
|/F||A single FMS with en route, terminal, and approach capability that meets the requirements of /E 1-4 above|
|/G||Global Positioning System (GPS)/Global navigation Satellite System (GNSS) equipped aircraft with en route, terminal, and GPS approach capability|
|/R||Required Navigational Performance. (Denotes capability to operate in RNP designated airspace and routes)|
|/W||Reduced Vertical Separation Minima (RVSM)|