Terminal control area (TMA) shall be established of sufficient size to contain the controlled traffic (IFR and VFR) around the busier vicinity of one or more major aerodromes, (within TMA controlled airspace) which are controlled by the unit provides approach control service.

The lateral limits of terminal control area normally between an average of 30 NM to 60 NM, and its shape may be such as a circle or other shape according to the included controlled aerodromes.

The vertical limits of TMA shall be established by a lower limit of a height above the ground or water not less than (700 ft), and up to flight level as coordinated between the approach control unit and area control center, and as such lateral and vertical limits determined by the appropriate ATS authority.
The need for TMA:

It is necessary to establish a TMA due to many factors affecting capacity of traffic and the need for TMA:
1. Number of available runways.
2. Geometry of the runways (intersecting, parallel, etc.).
3. Runway occupancy times.
4. Geometry of the taxiways (parallel, high speed, etc.).
5. Separation applied between aircraft.
6. Type of traffic;
- IFR/VFR ratio.
- Arrival/Departure ratio.
- Light/medium/heavy.
7. Approach aids available and their limitations.
8. Zoning limitations, or surrounding terrain within TMA.
9. Obstacle limitation surfaces, which need to be established to ensure a satisfactory level of safety.
10. Air traffic control staff (qualifications and experience).