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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 TypeExample Structure NameHeight above ground m/ftLocation
TV MastKVLY – TV Antenna629 metres / 2,063 feetUnited States (US)
ChimneysGRES-2 Power Station in420 metres / 1,377 feetKazakhstan
RadarDimona Radar Facility400 metres / 1,312 feetIsrael
Electricity PylonsZhoushan Island Overhead Powerline Tie370 metres / 1,214 feetChina
Meteorological TowerObninsk Meteorogical Tower315 metres / 1,034 feetRussia
Wind turbineVestas V164-8.0222 metres / 728 feetDenmark
TelescopeArecibo Telescope150 metres / 492 feetPuerto Rico
BuildingBurj Khalifa830 metres / 2,722 feetUnited 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]:

RankingTV Transmitter NameHeight above ground m/ftLocation
1Belmont343 metres / 1,125 feetLincolnshire, England
2Caldbeck320 metres / 1,050 feetCumbria, England
3Emley Moor317 metres / 1,040 feetWest Yorkshire, England
4Durris314 metres / 1,030 feetAberdeenshire, Scotland
5Arfon311 metres / 1,020 feetGwynedd, Wales
6Strabane309 metres / 1,014 feetStrabane, Northern Ireland
7Black Hill308 metres / 1,010 feetNorth Lanarkshire, Scotland
8Waltham301 metres / 988 feetLeicestershire, England
9Bilsdale296 metres / 971 feetNorth Yorkshire, England
10Mendip288 metres / 945 feetSomerset, 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]:

RankingBuilding NameHeight above ground m/ftLocation
1The Shard306 metres /  1,004 feetLondon, England
2One Canada Square236 metres /  774 feetLondon, England
3110 Bishopgate230 metres /  755 feetLondon, England
4The Leadenhall Building224 metres /  735 feetLondon, England
525 Canada Square201 metres /  659 feetLondon, England
68 Canada Square200 metres /  656 feetLondon, England
7Tower 42183 metres /  600 feetLondon, England
8The Tower, One St George Wharf181 metres /  594 feetLondon, England
930 St Mary Axe178 metres /  584 feetLondon, England
10Beetham Tower169 metres /  554 feetManchester, 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 NameHeight above ground m/ftLocation
10 Holloway Circus130 metres / 427 feetBirmingham, England
The Tower at Meridian Quay107 metres / 351 feetSwansea, Wales
Sky Plaza103 metres / 338 feetLeeds, England
St Paul’s Tower101 metres / 331 feetSheffield, England
109 Bluevale Street91 metres / 298 feetGlasgow, Scotland
Unity86 metres / 282 feetLiverpool, England
Obel Tower85 metres / 279 feetBelfast, Northern Ireland
Windsor House80 metres / 262 feetCardiff, Wales
Victoria Hall77 metres / 253 feetWolverhampton, England
The Mill and Jerwood Dance House71 metres / 233 feetIpswich, England
Martello Court64 metres / 210 feetEdinburgh, 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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