Indicators, signalling devices and markers
Learning objectives
- Explain how to read a wind sleeve, and why the sleeve at your landing field outranks a wind reported from somewhere else.
- Identify the landing T, the tower signalling lamp and the signal area: what each looks like, and why an aerodrome has it.
- Explain the difference between a marker and a marking, and identify which marker colour shows a taxiway edge and which shows a taxiway centre line.
- State which aerodromes the EU design rules cover, and why equipment may be missing or different at a small airfield.
The idea
Before radios, pilots learned about an airfield by looking at it. Some of those simple tools are still there. A cloth sleeve on a pole shows which way the air is moving. A big white T on the grass tells you which way to land. A lamp in the tower can talk to you with coloured light. Small posts beside the ground show where the hard surface ends. This lesson is about what each of these looks like and what to do with it.
Where these rules apply
The EU aerodrome design rules cover aerodromes that are open to public use, serve commercial air transport and have a paved instrument runway of 800 m or more.
A Member State may also exempt a small aerodrome from them, if it handles no more than 10 000 commercial passengers and no more than 850 cargo movements a year, and safety is not compromised. Military aerodromes are outside them too.
So many small airfields and farm strips are outside these rules, and everything below may be absent or different there. Where aerodrome data are published is taught in 010-08-01.
Before you fly to a small airfield, read its entry in the Aeronautical Information Publication (AIP).
The EU design standard is the rule in force. It is the EU version of ICAO Annex 14, and where the two really differ this lesson says so.
The EU design standard says "should", because it is a specification the aerodrome is certified against. The guidance around it is advice.
The wind sleeve
Why it exists
You need to know the wind where you will touch down, not the wind at an airport 13 NM away. An aerodrome therefore has enough wind direction indicators to give pilots wind information during approach and take-off. ICAO's Annex 14 differs here: it makes "at least one" the Standard and recommends lighting at least one at night, while the EU text asks for a "sufficient number".
A sufficient number of wind direction indicators for approach and take-off. At least one is visible from aircraft in flight, during approach or on the movement area before take-off, and it is sited clear of air disturbance from nearby objects.
What it is
A wind direction indicator (wind sleeve, wind cone, windsock) is a fabric truncated cone, at least 3.6 m long and at least 0.9 m across at its larger end. It is free to swing, so it shows the surface wind direction and gives a general indication of wind speed.
Describe this figure
Three side views show a wind sleeve on a pole, with the wind blowing from left to right. In light wind it hangs limp, in moderate wind it is half-extended and in strong wind it is fully extended. The wide mouth is at the pole and the narrow tail points downwind. Below, a two-colour sleeve has five alternate bands: bands 1, 3 and 5 orange and bands 2 and 4 white, so the first and last are the darker colour.
The figure shows three side views of the sleeve: hanging limp in light wind, half-extended in a moderate wind, and fully extended in a strong wind. In each, an arrow runs from the wide mouth to the narrow tail. Below them is a version in orange and white bands.
How to read it
The wide mouth faces into the wind, and the tail streams downwind. So the wind blows from the mouth towards the tail.
The more fully the sleeve stands out, the stronger the wind. It gives you a feel, not a number in knots.
Guidance for aerodrome designers says a cone that extends fully at about 15 kt is most useful, because 15 kt is described as the maximum crosswind landing component for small aircraft. That is a guide for choosing a sleeve. It is not your limit. Your crosswind figure, often a "maximum demonstrated crosswind", is in your aircraft's POH/AFM. Check your aircraft's POH/AFM. This lesson does not replace ATO instruction or the aircraft's POH/AFM.
Colours and night
The sleeve should be clearly visible and understandable from a height of at least 300 m. It is one colour where practicable. Where two colours are needed against changing backgrounds, the preferred pairs are orange and white, red and white, or black and white. Five alternate bands are used, and the first and last bands are the darker colour.
At an aerodrome intended for night use, a sufficient number of sleeves are illuminated.
Where you find it
At least one sleeve should be visible from aircraft in flight, during approach or on the movement area before take-off. It should sit clear of air disturbance from nearby objects such as buildings and trees. To help you spot it, at least one sleeve is ideally surrounded by a circular band on the ground, 15 m across and 1.2 m wide, preferably white.
Describe this figure
A plan view, not to scale, shows a runway threshold. A dimension line marks 300 m to the ideal sleeve position and 600 m as the maximum. The ideal position is 80 m to the side of the centre line. A shaded preferred zone runs from 300 to 600 m out and up to 200 m from the runway edge. A zoomed inset shows the white locating circle, 15 m across, with a band 1.2 m wide.
The figure is a plan view of a runway with a threshold. The sleeve sits about 300 m along the runway and 80 m to the side of the centre line, inside a shaded zone. The white locating circle surrounds it.
The guidance is more detailed. An illuminated sleeve can be usefully read from about 1 km in good visibility, so it should be no more than 600 m from the threshold. The ideal spot, ignoring obstacle criteria, is 300 m from the threshold along the runway and 80 m to the side of the centre line. A single sleeve can serve both runway ends only when the thresholds are less than 1 200 m apart. Guidance also prefers a spot no more than about 200 m from the runway edge.
Look at the sleeve on every approach and before take-off. Compare it with the wind passed by radio (ATIS, tower or AFIS). A sleeve sheltered by trees or buildings may not show the wind a few hundred feet higher.
The landing T
Why the landing T exists
A landing direction indicator is a device that shows the direction currently designated for landing and take-off. It is not a wind indicator. A person sets it, and the wind sleeve shows what the air is actually doing.
What it looks like
The landing T is a T lying flat on the ground, seen from above. The cross arm is a bar 4 m long and 0.4 m wide. The shaft is a bar 0.4 m wide, running 4 m out from the cross arm, joined at its middle. These are minimum sizes.
It is white or orange, whichever contrasts best with the background. At night it is either illuminated or outlined by white lights. It sits on a pedestal that is free to turn about a vertical axis, so it can be set in any direction.
Describe this figure
A white T lies flat on a darker pedestal, seen from above. The cross arm is 4 m long and 0.4 m wide, and the shaft is 4 m long and 0.4 m wide, as minimum sizes. A ghost aeroplane flies along the shaft towards the cross arm. By night the same T is outlined by white lights, or illuminated. The T may be orange instead of white, whichever contrasts best.
The figure shows a white T on a darker pedestal, seen from above. A ghost aeroplane lands along the shaft, flying towards the cross arm. A night version shows the same T outlined with white lights.
The meaning, in short: land and take off parallel to the shaft, towards the cross arm. The full set of ground signals is taught in 010-05-04.
Landing T indicators are provided only where an aerodrome chooses to have one, and they are seldom used. Someone has to turn them every time the wind shifts.
The tower signalling lamp
Why the signalling lamp exists
If your radio fails, the tower still has a way to talk to you. A controlled aerodrome has a signalling lamp in the control tower. The lamp is the tower's back-up way to talk to an aircraft with no radio, or one that has lost two-way radio contact.
A signalling lamp is provided in the tower at a controlled aerodrome, with red, green and white signals.
If your radio fails near a controlled aerodrome, keep a lookout towards the tower for light signals.
What it does
It produces red, green and white signals. It is aimed by hand at any target, and it can give one colour followed by either of the other two.
The beam is narrow, with a spread of between 1° and 3°, and negligible light beyond 3°. For daytime use the coloured light intensity should be at least 6 000 cd (candela).
Describe this figure
A control tower with a signalling lamp sends a thin cone of light to one aeroplane on final. The beam spread is 1° to 3° and the lamp is aimed by hand. A second aeroplane higher up and outside the cone sees nothing, so a light you see is meant for you. A legend lists the three colours, red, green and white, and says the lamp never shows amber.
The figure shows a tower with a lamp and a thin cone of light aimed at one aeroplane on final. A second aeroplane, outside the cone, sees nothing. A legend lists red, green and white.
Because the beam is narrow and aimed at one aircraft, a light signal you see is meant for you. What each colour means is taught in 010-05-04. The lamp never shows amber.
Signal panels and the signal area
Why they exist
At an aerodrome with no tower and no AFIS unit, or one used by aeroplanes without radio, the only way to pass a message to an aircraft overhead is to show it on the ground. A signal area with signal panels should be provided when visual ground signals are used to communicate with aircraft in flight.
The EU design text has no binding specification for them. All of this is guidance material. ICAO's Annex 14 puts the signal area in its main text, but the values are the same.
What the panels and signal area look like
The signal area is a level, even, horizontal surface, at least 9 m square. It is coloured to contrast with the panels shown on it, and it is surrounded by a white border at least 0.3 m wide. It should be visible in all directions at elevation angles above 10°, seen from 300 m height.
Describe this figure
The top view shows a level square signal area with a white border and one example panel. It is at least 9 m square and the border is at least 0.3 m wide. The side view shows the area on the ground with a dashed line rising 10° above the horizontal. The area should be visible from every direction above that line when seen from 300 m height, where an aeroplane is drawn.
The figure shows a square signal area with a white border, seen from an aeroplane at 300 m height. A 10° line above the horizon marks the visibility rule. One example panel lies on the area.
The shape, colour and meaning of each ground signal belong to the rules of the air. See 010-05-04.
At a non-radio or uncontrolled aerodrome, read the signal area when you overfly or join, before you descend into the circuit.
Markers
Marker or marking?
A marker is an object displayed above ground level to indicate an obstacle or delineate a boundary. A marking is a symbol or group of symbols on the surface of the movement area. Markers stand up. Markings are painted flat. Markings are taught in 010-09-03.
| Question | Marker | Marking |
|---|---|---|
| What is it? | An object displayed above ground level, to indicate an obstacle or delineate a boundary. | A symbol or group of symbols displayed on the surface of the movement area, to convey aeronautical information. |
| Where is it? | Above the ground. It stands up. | On the surface. It is painted flat. |
| Examples in this lesson | Boards or cones along an unpaved runway. Blue taxiway edge posts. Green taxiway centre line markers. | The painted yellow taxiway centre line. A centre line marker sits on it. |
| If you hit it | Markers should be frangible: low mass, designed to break or yield, so they are the least hazard to aircraft. | Nothing to hit: it is flat on the surface. |
| Taught in | This lesson (010-09-02). | Lesson 010-09-03. |
Describe this figure
The table compares a marker and a marking in five rows. A marker is an object above ground level, and a marking is a symbol on the surface of the movement area. Examples of markers are boards, cones and coloured posts. A marker should be frangible, and markings are taught in lesson 010-09-03.
The figure is a two-column table: marker (above ground, with examples) and marking (on the surface, with examples).
General requirements
All markers should be frangible. A frangible object has low mass and is designed to break, distort or yield on impact, so it is the least hazard to aircraft. Markers near a runway or taxiway should be low enough to keep clearance for propellers and for jet engine pods.
Unpaved runway markers
On an unpaved runway, markers are provided when the surface itself does not clearly show where the runway ends. Where runway lights exist, the markers are built into the light fixtures. Where there are no lights, flat rectangular markers or conical markers delimit the runway.
Flat rectangular markers are at least 1 m × 3 m, with the long side parallel to the runway centre line. Conical markers are not more than 0.50 m high.
Describe this figure
A plan view shows an unpaved runway with no visible edge, delimited by flat rectangular boards along both sides, long sides parallel to the centre line. One board is enlarged and labelled at least 1 m by 3 m, with no colour specified. The alternative is a conical marker not more than 0.50 m high. Where runway lights exist, the marker is built into the light fixture.
The figure shows a grass runway with flat rectangular boards along both sides, long sides parallel to the centre line. Cones are shown as an alternative. An inset shows a marker built into a light fixture.
Stopway and snow markers
Stopway edge markers are provided when the extent of a stopway is not clear from its appearance. They should be different enough from runway edge markers that the two cannot be confused.
On a snow-covered runway, edge markers show the usable limits when these are not otherwise indicated. They are placed along both sides at intervals of not more than 100 m, symmetric about the centre line and far enough out to clear wing tips and engines. Enough markers are placed across the threshold and the runway end.
Taxiway markers: blue edge, green centre line
Colours do the work here, the same colours as taxiway lights. Blue means taxiway edge. Green means taxiway centre line.
Taxiway edge markers are provided on a taxiway with no centre line lights, no edge lights and no centre line markers. They are retroreflective blue, which means they shine light back towards its source, such as your taxi light. The face you see is a rectangle of at least 150 cm². Guidance says they are spaced not more than 60 m apart on straight sections, closer on curves, and as near as practicable to the edge or not more than 3 m outside it. A common design is a cylinder 75 mm wide, no more than 35 cm above the surface ideally, with a 200 mm retroreflective sleeve.
Taxiway centre line markers are provided where there are no centre line lights, no edge lights and no edge markers, or where the painted centre line needs better guidance. They sit on the painted centre line, or not more than 0.3 m off it where that is impracticable. They are retroreflective green, with a face of at least 20 cm², and are designed to be run over by aircraft wheels without damage.
Describe this figure
A plan view shows an unlit taxiway that runs straight and then curves. Blue edge markers run along both edges, no more than 60 m apart on straights and closer on the curve. Green markers sit on the yellow painted centre line and can be run over. A side view shows the blue post: dark cap, 200 mm retroreflective sleeve, dark band, collar and stem, 75 mm wide.
The figure is a plan view of an unlit taxiway. Blue edge markers run along both edges, closer together around a curve. Green markers sit on the yellow centre line. A side-view inset shows the blue post with its dark cap, 200 mm sleeve, dark band, collar and stem.
An edge marker shows where the paved surface ends, so it is not designed to be run over. A centre line marker is designed to be.
ICAO's Annex 14 recommends edge and centre line markers on taxiways with code number 1 or 2. The EU text has no code-number condition. The colours and viewing areas are the same.
Unpaved taxiway edge markers are provided where the extent of an unpaved taxiway is not clear from its appearance. They are built into the light fixtures where taxiway lights exist, and otherwise suitable markers delineate the taxiway.
| Device | Where it is | What it tells you | Colours | At night |
|---|---|---|---|---|
| Wind sleeveA requirement for the aerodrome | Visible from the air or on the movement area before take-off; clear of air disturbance. | Surface wind direction, and a general idea of wind speed. The wide mouth faces into the wind. | One colour where practicable. Otherwise orange and white, red and white, or black and white, in five bands, first and last darker. | A sufficient number are illuminated at an aerodrome used at night. |
| Landing TOnly where provided | A conspicuous place on the aerodrome, on a pedestal that turns. | The direction designated for landing and take-off: land and take off parallel to the shaft, towards the cross arm. Set by a person. | White or orange, whichever contrasts best. | Illuminated, or outlined by white lights. |
| Signalling lampA requirement at a controlled aerodrome | In the control tower, aimed by hand at one target. | A signal for you from the tower; its meanings are in lesson 010-05-04. The beam is narrow, 1° to 3°. | Red, green and white. It never shows amber. | It is itself a light. It has a secondary power supply. |
| Signal area and panelsGuidance only | A signal area on the aerodrome, where ground signals are used to talk to aircraft in flight. | Messages shown on the ground; the signals themselves are in lesson 010-05-04. Level, even, at least 9 m square. | Coloured to contrast with the panels, with a white border at least 0.3 m wide. | No night provision is stated. |
| Taxiway markersA requirement where the stated conditions apply | Along the edges of a taxiway, or on its centre line, where there are no lights. | Blue: taxiway edge, where the paved surface ends. Green: taxiway centre line, can be run over. | Retroreflective blue (edge) and green (centre line). | Retroreflective: they shine back in your taxi light. |
Describe this figure
The table has one row for each device. It gives where the device is, what it tells the pilot, its colours and its night provision. The wind sleeve shows wind, the landing T the designated direction and the lamp a signal for you. The signal area is guidance only, and taxiway markers are blue for edge and green for centre line.
The summary figure is a table of each device: where it is, what it tells you, its colours, and its night provision.
In the real world
In June 2017 a pilot flew to a farm airstrip in Norfolk, UK. He did not look at the windsock and relied on the wind reported at an airport about 13 NM away, which differed from the local wind. He landed downwind on runway 11. The accident investigation board linked the accident to not identifying the local wind. The lesson: the windsock shows the wind where you are landing.
At Popham, UK, in June 2003, the windsock showed a light and variable wind before take-off. The pilot later said it did not show the wind he met above the trees. The investigators noted the wind may have changed and that the windsock was below the tree line, so it could not represent the wind above the trees. The lesson: siting matters, and a sleeve shows surface wind only.
Both are UK general aviation airfields, used here for the pilot lesson only, not as examples of EU rule compliance.
Exam traps
"The windsock points where the wind is coming from." Wrong. The tail points downwind. The wind comes from the open, wide mouth end.
"A fully extended windsock means exactly 15 kt, and 15 kt is my crosswind limit." Wrong. The sleeve gives only a general speed indication. The 15 kt is a design guide for choosing a sleeve, and your limit is in the POH/AFM.
"The landing T shows where the wind comes from, like a windsock." Wrong. It shows the direction designated for landing and take-off, and a person sets it, so it can lag a wind change.
"Taxiway edge markers are green and centre line markers are blue." Wrong. Edge is blue and centre line is green.
"The signalling lamp can show amber, and every aerodrome must have a signal area." Wrong on both. The lamp gives red, green and white only. The signal area is guidance, used where ground signals are used.
Explain it back
You are approaching a small airfield with no radio service. The only wind report you have is from an airport 20 NM away. Explain what you would look at on the ground to decide your landing direction, and what each of the wind sleeve, the landing T and the signal area would tell you.
Self-check
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Scenario: you are CS-ABC, joining an airfield with no radio service. It has runways 11 and 29. The wind reported by an airport 13 NM away favours runway 11. Overhead, you see the airfield's wind sleeve fully extended, its wide mouth pointing west and its tail streaming east. The landing T is set for runway 29. What do you do?mcq · hard
Show answer
The wide mouth faces into the wind and the tail streams downwind, so a sleeve with its mouth to the west shows wind from the west, which favours runway 29. The sleeve shows the local surface wind, which can differ from a report made 13 NM away, as a real accident showed. The landing T shows the direction designated for use, not the wind, and a person sets it, so it can lag. Here the two agree. Runway 11 comes from reading the tail as the wind source, or from trusting the distant report over the local indicator.
Reference: CS ADR-DSN.K.490(b); CS ADR-DSN.K.490(c)(2); CS ADR-DSN.A.002
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Scenario: a grass airfield has no control tower and no AFIS unit, and some visiting aeroplanes have no radio. Which description of the visual means is correct?mcq · medium
Show answer
Guidance describes a signal area with signal panels for aerodromes with no tower and no AFIS unit, or used by aeroplanes without radio. It is guidance, not a requirement everywhere. The signalling lamp is provided in the tower of a controlled aerodrome and gives red, green and white, never amber, in a narrow beam aimed by hand at one aircraft. A wide beam would defeat its purpose, and the landing T shows the designated direction rather than carrying ground signals.
Reference: GM1 ADR-DSN.K.505(a); GM1 ADR-DSN.K.505(b); CS ADR-DSN.K.500(a); CS ADR-DSN.K.500(b)(1)-(2)
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A grass runway has no lights. Which arrangement delimits it, and what applies to every marker near a runway or taxiway?mcq · medium
Show answer
Without lights, flat rectangular markers of at least 1 m × 3 m with the long side parallel to the centre line, or cones of no more than 0.50 m, delimit an unpaved runway. A marker is an object above the surface, and all markers should be frangible, with low mass, so they break or yield on impact and are low enough to clear propellers and engine pods. The second option has the board orientation wrong, a cone minimum instead of a maximum, and rigid markers. The third borrows the blue taxiway edge colour and spacing. The fourth turns the board size into a maximum and wants tall markers.
Reference: CS ADR-DSN.A.002; CS ADR-DSN.P.805; CS ADR-DSN.P.810(b)(2)
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At night you taxi on an unlit taxiway. You see blue retroreflective posts at the sides and green retroreflective markers set along the middle. What do they show?mcq · easy
Show answer
Blue means taxiway edge and green means taxiway centre line, the same colours as taxiway lights. Centre line markers are designed to be run over by aircraft wheels, while edge markers show where the paved surface ends. The first option swaps the colours. The fourth uses colours that belong to taxiways. Runway and stopway edge markers only need to differ from each other.
Reference: CS ADR-DSN.P.825(c); CS ADR-DSN.P.830(c)
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A student expects every small airfield in the EU to have a landing T and a signal area built to the EU design rules. Which statement is correct?mcq · medium
Show answer
The EU aerodrome rules cover public-use aerodromes with commercial air transport and a paved instrument runway of 800 m or more, and a Member State may exempt very small ones. Military aerodromes are outside them. The landing T and signal area are optional, not forbidden. Read the AIP entry for the field you plan to use.
Reference: Reg. (EU) 2018/1139 Art. 2(1)(e); Reg. (EU) 2018/1139 Art. 2(7)
Key concepts
Written with ASD-STE100 writing principles: short sentences, one topic per sentence, active voice, one word for one meaning.
Wind direction indicator
A wind direction indicator is a fabric truncated cone that shows the surface wind direction. Its wide mouth faces into the wind, so the wind blows from the mouth towards the tail. It is at least 3.6 m long and 0.9 m across at its larger end.
Rule: CS ADR-DSN.K.490(c)(1)
Do not: read the tail as the place the wind comes from.
Local wind check
The design text asks for at least one wind direction indicator visible from aircraft in flight, during approach or on the movement area before take-off. The indicator shows only the local surface wind, so it can differ from a wind reported elsewhere.
Rule: CS ADR-DSN.K.490(b)
Do: compare the indicator with the wind passed by radio on every approach.
Taxiway marker colours
A taxiway edge marker is retroreflective blue, and a taxiway centre line marker is retroreflective green. The edge marker shows where the paved surface ends. The centre line marker is designed to be crossed by aircraft wheels without damage.
Rule: CS ADR-DSN.P.825(c) and CS ADR-DSN.P.830(c)
Note: an edge marker shows where the paved surface ends and is not designed to be run over.
Landing T
A landing T is a T-shaped ground signal that shows the direction for landing and take-off. It is white or orange, whichever contrasts best with the background. At night, it is illuminated or outlined by white lights.
Rule: CS ADR-DSN.K.495(b)(3) and CS ADR-DSN.K.495(b)(4)
Do: land towards the cross arm, parallel to the shaft.
Signalling lamp
A controlled aerodrome has a signalling lamp in its control tower. The lamp is hand-aimed and gives red, green and white signals. Its beam spread is between 1° and 3°, and its daytime coloured light intensity is at least 6 000 cd.
Rule: CS ADR-DSN.K.500(a) and CS ADR-DSN.K.500(b)(1)-(2)
Signal area
A signal area is an area on an aerodrome where ground signals are displayed. Guidance says the signal area is a level, even surface at least 9 m square, with a white border at least 0.3 m wide. Guidance says a signal area is useful at an aerodrome with no tower and no AFIS unit.
Marker and marking
A marker is an object displayed above ground level to indicate an obstacle or delineate a boundary. A marking is a symbol on the surface of the movement area that conveys aeronautical information.
Frangible markers
Markers near a runway or taxiway are low enough to keep propeller and engine pod clearance. All markers are frangible. A frangible object has low mass and is designed to break, distort or yield on impact. Flat boards of at least 1 m × 3 m, or cones of no more than 0.50 m high, delimit an unpaved runway without lights.
Rule: CS ADR-DSN.P.805 and CS ADR-DSN.P.810(b)(2)
Flashcards
Print them: A6 landscape cards (PDF, front and back) · 4 cards per A4 landscape sheet (PDF, cut lines) · Key figures deck (PDF, 43 figures)
Print double-sided, flip on the short edge.
010-09-02-01Which end of a wind direction indicator faces into the wind?
The wide mouth. The wind blows from the mouth towards the tail.
010-09-02-02Minimum length of a wind direction indicator?
3.6 m.
010-09-02-03Minimum diameter at the larger end of a wind direction indicator?
0.9 m.
010-09-02-04Height from which a wind direction indicator is clearly visible and understandable?
At least 300 m.
010-09-02-05How many alternate bands on a two-colour wind direction indicator?
Five bands. The first and last bands use the darker colour.
010-09-02-06What does a fully extended wind direction indicator show about wind speed?
A general idea of speed. It does not give a reading in knots.
010-09-02-07Why is a cone that extends fully at about 15 kt useful to pilots?
Guidance uses 15 kt to choose a cone. Your crosswind limit is in your aircraft's POH/AFM.
010-09-02-08Where is at least one wind direction indicator visible?
From aircraft in flight, during approach or on the movement area before take-off.
010-09-02-09Why compare a wind direction indicator with the wind passed by radio?
The indicator shows only the local surface wind, which can differ from a wind reported elsewhere.
010-09-02-10Circular band around a wind direction indicator, and its width?
Guidance: 15 m across and 1.2 m wide, preferably white, to help pilots find it.
010-09-02-11Guidance: distance at which an illuminated wind direction indicator is usefully read?
About 1 km, in good visibility.
010-09-02-12Guidance: maximum distance of a wind direction indicator from the runway threshold, for approach?
600 m.
010-09-02-13Guidance: ideal position of a wind direction indicator along and beside the runway?
300 m along the runway from the threshold, and 80 m to the side of the centre line.
010-09-02-14Guidance: when can one wind direction indicator serve both runway ends?
When the thresholds are less than 1 200 m apart.
010-09-02-15Guidance: preferred lateral distance of a wind direction indicator from the runway edge?
No more than about 200 m.
010-09-02-16What colour is a taxiway edge marker?
Retroreflective blue.
010-09-02-17What colour is a taxiway centre line marker, and can aircraft wheels pass over it?
Retroreflective green. It is designed to be crossed by aircraft wheels without damage.
010-09-02-18Is a taxiway edge marker designed to be run over?
No. It shows where the paved surface ends. Centre line markers are the ones designed to be crossed.
010-09-02-19Minimum viewing area of a taxiway edge marker?
150 cm².
010-09-02-20Guidance: maximum spacing of taxiway edge markers on a straight section?
60 m. Markers are closer together on curves.
010-09-02-21Minimum viewing area of a taxiway centre line marker?
20 cm².
010-09-02-22Maximum offset of a taxiway centre line marker from the painted centre line?
0.3 m, where placing it on the marking is impracticable.
010-09-02-23Minimum size of the landing T cross arm and shaft?
Cross arm: 4 m long, 0.4 m wide. Shaft: 0.4 m wide, running 4 m out from the cross arm, joined at its middle.
010-09-02-24Colour of a landing T?
White or orange, whichever contrasts best with the background.
010-09-02-25How is a landing T shown at night?
Illuminated, or outlined by white lights.
010-09-02-26Which way do you land relative to a landing T?
Parallel to the shaft and towards the cross arm.
010-09-02-27Where is a signalling lamp provided?
In the control tower at a controlled aerodrome.
010-09-02-28Which signals does a signalling lamp produce?
Red, green and white.
010-09-02-29Beam spread of a signalling lamp?
Between 1° and 3°, with negligible light beyond 3°.
010-09-02-30Minimum coloured light intensity of a signalling lamp for daytime use?
6 000 cd.
010-09-02-31Can a signalling lamp show amber?
No. It gives red, green and white signals only.
010-09-02-32Guidance: minimum size of a signal area?
At least 9 m square, with a white border at least 0.3 m wide.
010-09-02-33Guidance: elevation above the horizontal at which a signal area is visible in all directions?
Above 10°, when seen from 300 m height.
010-09-02-34When is a signal area useful?
Guidance: at an aerodrome with no tower and no AFIS unit, when visual ground signals are used.
010-09-02-35What is a marker?
An object above ground level that indicates an obstacle or delineates a boundary.
010-09-02-36What is a marking?
A symbol on the surface of the movement area that conveys aeronautical information.
010-09-02-37Why are markers frangible and low?
A frangible object minimises harm on impact. Low markers keep clearance for propellers and engine pods.
010-09-02-38Size of a flat rectangular edge marker on an unpaved runway without lights?
At least 1 m × 3 m, with the long side parallel to the runway centre line.
010-09-02-39Maximum height of a conical edge marker on an unpaved runway?
0.50 m.
010-09-02-40Maximum interval of edge markers on a snow-covered runway, along each side?
100 m.
Sources
- Easy Access Rules for Aerodromes (Regulation (EU) No 139/2014), March 2026 revision, including CS ADR-DSN Issue 7 (Chapters K and P and associated GM1) and the Figure K-1 and Figure GM-P-1 drawings (EASA).
- Regulation (EU) 2018/1139 (Basic Regulation), Article 2, consolidated text of 2 August 2026 (EUR-Lex).
- Easy Access Rules for Standardised European Rules of the Air (SERA), August 2025, Appendix 1 (landing T meaning, cross-reference only).
- ICAO Annex 14, Volume I, Aerodrome Design and Operations, 9th edition (July 2022), consolidated to Amendment 18.
- AAIB Bulletin 09/2017, Extra EA 300/LC G-GOFF, Foxborough Farm airstrip, Norfolk, 17 June 2017. https://www.gov.uk/aaib-reports/aaib-investigation-to-extra-ea-300-lc-g-goff
- AAIB Bulletin 10/2003, Rans S6-ES Coyote II G-MZMS, Popham Airfield, 21 June 2003 (ref. EW/G2003/06/27). https://assets.publishing.service.gov.uk/media/5422ef87e5274a131400027f/dft_avsafety_pdf_024584.pdf
This page is educational. It does not replace instruction at your ATO or your aircraft's POH/AFM. Rules change: check the regulation in force.