The transition altitude is the upper limit from the surface to use the local QNH altimeter setting, applicable to all aircraft defined inside the associated TMA (terminal area) where it is published.
The transition level is the lower limit to use the standard 1013hPa altimeter setting, applicable to all aircraft defined inside the associated TMA (terminal area) where transition altitude is published.
The transition altitude (TA) is always 10.000ft.
The transition level is FL110 unless the QNH is in accordance with the following:
| QNH less than | Transition level (TRL) |
| 1013 hPa | FL115 |
| 997 hPa | FL120 |
| 980 hPa | FL125 |
| 963 hPa | FL130 |
Manual of Air Traffic Services (by Airservice Australia and Department of Defence) (9.3.1.3 - 9.3.1.4 > page 314)
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