Tall Structures Can Obstruct Aviation
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Tall structures that can obstruct aviation?

Tall structures that can obstruct aviation?
July 14, 2015 Jan Georgopoulos

Tall structures can obstruct flying and affect aviation safety when in the vicinity of an aerodrome and penetrate the obstacle limitation surfaces. Also they can be an En-Route obstacle when located between flying destinations [1].

Examples of Tall Structures

The term tall structure includes tall buildings, television (TV) masts, power plant chimneys, radar antennae, electricity pylons, wind turbines, construction cranes and other.

The Arecibo Telescope Tower at the Arecibo Observatory Puerto RicoFigure 1: A tall structure. The Arecibo Telescope Tower, Puerto Rico

An example list of tall structure types with specific examples from around the world is shown in the table below:

Tall Structure Type Example Structure Name Height above ground m/ft Location
TV Mast KVLY – TV Antenna 629 metres / 2,063 feet United States (US)
Chimneys GRES-2 Power Station in 420 metres / 1,377 feet Kazakhstan
Radar Dimona Radar Facility 400 metres / 1,312 feet Israel
Electricity Pylons Zhoushan Island Overhead Powerline Tie 370 metres / 1,214 feet China
Meteorological Tower Obninsk Meteorogical Tower 315 metres / 1,034 feet Russia
Wind turbine Vestas V164-8.0 222 metres / 728 feet Denmark
Telescope Arecibo Telescope 150 metres / 492 feet Puerto Rico
Building Burj Khalifa 830 metres / 2,722 feet United Arab Emirates (UAE)

Table 1: Example types of tall structures

In this article we focus on TV transmitters and Tall Buildings in the UK. However we have previously written about tall buildings affecting aviation activities in Australia and the US.

Tall Structures – TV Transmitters

In the UK there are over 1,150 TV transmitters distributed all over the country. Among which, 67 are main transmitters. Main TV transmitters are usually significantly taller than the rest due to the large areas they serve. Their average height in the UK is 155 metres / 508 feet above ground.

Emley Moor Television Transmitter, UKFigure 2: Emley Moor Television Transmitter UK

The 10 tallest TV transmitter structures in the UK are [2]:

Ranking TV Transmitter Name Height above ground m/ft Location
1 Belmont 343 metres / 1,125 feet Lincolnshire, England
2 Caldbeck 320 metres / 1,050 feet Cumbria, England
3 Emley Moor 317 metres / 1,040 feet West Yorkshire, England
4 Durris 314 metres / 1,030 feet Aberdeenshire, Scotland
5 Arfon 311 metres / 1,020 feet Gwynedd, Wales
6 Strabane 309 metres / 1,014 feet Strabane, Northern Ireland
7 Black Hill 308 metres / 1,010 feet North Lanarkshire, Scotland
8 Waltham 301 metres / 988 feet Leicestershire, England
9 Bilsdale 296 metres / 971 feet North Yorkshire, England
10 Mendip 288 metres / 945 feet Somerset, England

Table 2: The 10 tallest TV transmitters in the UK

These 10 transmitters can be seen in Figure 1 below.

The top 10 TV Transmitters in the UK, and their locations on the British Isles. Figure 3: The 10 tallest TV transmitters in the UK

The tallest TV transmitter structure in the UK is Belmont having a height of 343 metres / 1,125 feet. For comparisons, the tallest TV transmitter in the world appears to be KVLY – TV Antenna in North Dakota, USA having a height of 629 metres / 2,063 feet.

Belmont Television TransmitterFigure 4: Belmont Television Transmitter UK

Tall Structures – Buildings (Residential, Offices, Hotels)

In the UK there are numerous tall buildings the vast majority of which are located in London and are usually residential, offices and hotels. The 10 tallest buildings in the UK are [3]:

Ranking Building Name Height above ground m/ft Location
1 The Shard 306 metres /  1,004 feet London, England
2 One Canada Square 236 metres /  774 feet London, England
3 110 Bishopgate 230 metres /  755 feet London, England
4 The Leadenhall Building 224 metres /  735 feet London, England
5 25 Canada Square 201 metres /  659 feet London, England
6 8 Canada Square 200 metres /  656 feet London, England
7 Tower 42 183 metres /  600 feet London, England
8 The Tower, One St George Wharf 181 metres /  594 feet London, England
9 30 St Mary Axe 178 metres /  584 feet London, England
10 Beetham Tower 169 metres /  554 feet Manchester, England

Table 3: The 10 tallest Buildings in the UK

The tallest building in the UK is the Shard which has an overall height of 306 metres / 1,004 feet. For comparisons, the tallest building in the world is currently Burj Khalifa having a height of 828 metres / 2,717 feet.

The Shard, LondonFigure 5: The Shard (Left hand side), London, in comparison to other tall buildings and construction cranes

Other UK cities with tall buildings include:

Building Name Height above ground m/ft Location
10 Holloway Circus 130 metres / 427 feet Birmingham, England
The Tower at Meridian Quay 107 metres / 351 feet Swansea, Wales
Sky Plaza 103 metres / 338 feet Leeds, England
St Paul’s Tower 101 metres / 331 feet Sheffield, England
109 Bluevale Street 91 metres / 298 feet Glasgow, Scotland
Unity 86 metres / 282 feet Liverpool, England
Obel Tower 85 metres / 279 feet Belfast, Northern Ireland
Windsor House 80 metres / 262 feet Cardiff, Wales
Victoria Hall 77 metres / 253 feet Wolverhampton, England
The Mill and Jerwood Dance House 71 metres / 233 feet Ipswich, England
Martello Court 64 metres / 210 feet Edinburgh, Scotland

Table 4: The tallest Buildings in the UK outside London

Aviation Warning Lights

Any tall structure penetrating any obstacle limitation surfaces (vicinity of an aerodrome) or having a height of 150 metres and above (away from an aerodrome) needs be lit [4]. There could be instances where tall structures with heights less than 150 metres will also need to be lit. You can read more about wind turbine aeronautical lighting requirement here.


There are many different types of tall structures that can affect aviation safety. These include TV masts, power plant chimneys, radar antennae, electricity pylons, meteorological towers, wind turbines, telescopes, construction cranes and of course tall buildings (e.g. commercial, offices, hotels).

In the UK there are 67 main TV transmitters with an average height of 155 metres / 508 feet above ground. These are located throughout the UK.

In the UK the vast majority of tall buildings are located in London. Outside London tall buildings exist in urban environments such as Manchester, Birmingham, Leeds, Liverpool, Swansea, Edinburgh, Glasgow, Cardiff, Belfast and other.

Tall structures are likely to keep increasing in numbers. When planning for such developments it is recommended to investigate whether there could be any aviation concerns which could constrain the structure’s height.

Image accreditations: “Tower from Afar” by Jeff Hitchcock / CC BY 2.0 / changes have been made from original.

Belmont TV Mast – geograph.org.uk – 15129” by Andy Beecroft  via Wikimedia Commons / CC BY-SA 2.0 / Image resized.

Emley Moor TV Mast – geograph.org.uk – 1016768” By Ratsbew  via Wikimedia Commons / CC BY-SA 3.0 / Image cropped and resized from original.


[1] Article 219 of the Air Navigation Order (published within CAP393) states that a tall structure having a height of 150 metres or more above ground level can be an En-route obstacle.

[2] Ofcom – UK Digital Television Transmitter Details via www.ofcom.org.uk (last accessed 13/07/2015).

[3] The Skyscraper Center (last accessed 13/07/2015).

[4] CAP393 – Air Navigation: The Order and Regulations by The Office of the General Counsel, Civil Aviation Authority (last accessed 13/07/2015).


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