Refer to figure.
AIP SOUTH AFRICA
ENR 1.7 ALTIMETER SETTING PROCEDURES

4 Transition Levels

d) In VMC, flights intending to land at points beyond 25 nautical miles from any of the aerodromes, listed in paragraph 3 (b), shall observe a height of 3000 feet above the ground or water as the transition level.

e) In IMC, flights intending to land at points beyond 25 nautical miles from any of the aerodromes, listed in paragraph 3 (b), shall observe the flight level 500 feet above
the lowest safe altitude as the transition level.

• Transition altitude → The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes using QNH.
• Transition level → The lowest flight level available for use above the transition altitude. At or above the transition level 1013.2 hPa pressure setting is used and the altimeter indicates flight levels.
• Transition layer → The airspace between the transition altitude and the transition level. When climbing through this layer 1013.2 hPa setting is used and the altimeter indicates flight levels, and when descending through this layer QNH is used and the altimeter indicates altitudes.