Exams
Weather
Aircraft Information
General Knowledge
- VFR Circuit
- VFR Minima
- Airspace
- ATC Air Traffic Control
- Flight Rules
- Overhead Join
- QNH/QFE/QNE
- TA Transition Altitude TL Transition Level Semicircular Rule
ATC Services
CAA Phraseology
- Free Call Technique
- CAA AGCS VFR Circuits
- CAA AGCS Arrivals
- CAA AGCS Departures
- CAA AGCS RNP Approach
- CAA AFIS VFR Circuit
- CAA AFIS Arriving
- CAA AFIS Departure
- CAA AFIS RNP Approach
- CAA ATC VFR Circuit
- CAA ATC VFR Arrivals
- CAA ATC VFR Departure
- CAA ATC VFR Transit Class D
ICAO Phraseology
- ICAO AFIS Circuits
- ICAO AFIS Arrival
- ICAO AFIS Departure
- ICAO ATC Arrival
- ICAO ATC Departure
In this lesson, we shall talk about the difference between the TA and TL/TRL.
Transition Altitude (TA).
The Transition Altitude within the UK is 3000 FT except in, or beneath, that Airspace specified in the table within the (Where to find the transition altitude section below.)
The TA is the upper limit from the surface to use the local QNH altimeter setting. For example, at Leeds Bradford, the TA is 5000ft so if operating below 5000ft you would remain on the local QNH published in the ATIS or given by ATC. I would advise that you also set the local QNH when operating near controlled airspace.
Each hectopascal is around 30ft, at the time of writing this the regional pressure setting (Information on the regional pressure in the weather course) is 1024 hPa, Leeds Bradford QNH is 1028, a difference is 120ft. So if you were flying 1900ft just below the controlled airspace you would have breached controlled airspace by 30ft. The regional pressure I got from the Met Office briefing service and Sherburn and Leeds are in the Barnsley region.
Where to find the Transition Altitude.
You can find the transition Altitude on the airport charts. It is generally shown on arrival departure and approach charts. NATS document ENR 1.7 also provides the information in the table below.
| Aberdeen CTR/CTA | 6000 FT |
| Belfast CTR/TMA | 6000 FT |
| Birmingham CTR/CTA | 6000 FT |
| Bristol CTR/CTA | 6000 FT |
| Cardiff CTR/CTA | 6000 FT |
| Channel Islands CTR/CTA | 5000 FT |
| Clacton CTA | 6000 FT |
| Daventry CTA | 6000 FT |
| East Midlands CTR/CTA | 6000 FT |
| East Midlands CTR/CTA | 6000 FT |
| Edinburgh CTR/CTA | 6000 FT |
| Glasgow CTR/CTA | 6000 FT |
| Leeds Bradford CTR/CTA | 5000 FT † |
| Liverpool CTR/CTA | 5000 FT |
| London TMA | 6000 FT |
| Manchester TMA | 5000 FT |
| Newcastle CTR/CTA | 6000 FT |
| Norwich CTR/CTA | 5000 FT † |
| Scottish TMA | 6000 FT |
| Solent CTA | 6000 FT † |
| Sumburgh CTR/CTA | 6000 FT † |
| Teesside International CTR/CTA | 6000 FT † |
| Worthing CTA 1, 2, 3 and 5 | 6000 FT |
| Note: † Outside the notified hours of operation the Transition Altitude is 3000 FT. | |
Transition Level (TRL)
The TL/TRL is the lower limit to use the standard 1013 hPA altimeter setting, so if you are flying at 5500ft and using the standard setting 1013, once you pass below the transition level you should switch to the local QNH/QFE. The transition level unlike the TA is not static it changes based on the QNH,
| Transition Altitude 3000ft | |
| 977 – 994 | FL050 |
| 995 – 1013 | FL045 |
| 1013 – 1031 | FL040 |
| 1032 – 1049 | FL030 |
| Transition Altitude 5000ft | |
| 977 – 994 | FL070 |
| 995 – 1013 | FL065 |
| 1013 – 1031 | FL060 |
| 1032 – 1049 | FL055 |
| Transition Altitude 6000ft | |
| 977 – 994 | FL080 |
| 995 – 1013 | FL075 |
| 1013 – 1031 | FL070 |
| 1032 – 1049 | FL065 |
Transition Layer
The transition layer is the airspace located between the transition altitude and the transition level. The transition layer is defined inside the associated TMA (terminal area) where the transition altitude is published. No cruise flight in the transition layer is permitted. An aircraft can only cross the transition layer.
Semicircular rules.
Depending on the direction you are travelling you should use the appropriate flight levels. So if going from Sherburn to Blackpool you be travelling between 180-359 degrees so should select and even flight level.