AIRPORT VISUAL AIDS AND AIR TRAFFIC CONTROL

2. AIRPORT DESIGN
Runway Design: Orientation, Wind Rose
Diagram, Problems on basic and Actual Length,
Geometric Design – Elements of Taxiway
Design – Airport Zones – Passenger Facilities
and Services – Runway and Taxiway Markings.

3. RUNWAY ORIENTATION:
 Oriented in the direction of prevailing winds.
 Head wind i.e., wind blowing in opposite direction to landing
and take off provides greater lift on the wings of the aircraft
while taking off.
 So that aircraft rises above ground much earlier and in shorter
length of runway.
 While landing, head wind provides a braking effect on aircraft
and makes it comes to stop in smaller length of runway.

4.  Centre line of runway is oriented along prevailing wind
direction.
 But it is not possible to obtain direction of wind along the centre
line of a runway throughout a year.
 On some days of year and few hours of a day, wind may blow
making certain angle with centre line of runway.

5.  If angle between centre line and direction of wind is θ, the
component along the direction of runway is Vcosθ and the
component normal to the runway is Vsinθ, where ‘V’ is wind
velocity.
 The normal component ‘Vsinθ’ is termed as cross wind
component.

7.  The cross wind component is very dangerous and may interrupt
safe landing and take off operations.
 As per ICAO, following are permissible cross wind components.

26.  Pilot needs visual aids while landing and take off during all
weather and at every time.
 Runway threshold, runway edges and the runway centre line
should be clearly visible.

27. Airport Marking: The airport markings are divided in to
following categories
i)Runway marking
ii)Taxiway marking
iii)Runway and taxiway shoulder marking
iv)Apron marking
v)Wind direction indicator
vi)Landing direction indicator

28. i)Runway Marking:
a)Runway threshold marking
b)Runway touch down zone or landing zone mark
c)Runway edge strip marking
d)Runway centreline marking
e)Runway number

29. f)If there are two or more number of parallel runways, they are
marked as follows at threshold:
i)Two parallel runways: L, R
ii)Three parallel runways: L, C, R
iii)Four parallel runways: L, LC, RC, R.

31. a) Runway Threshold Marking
 The runway threshold is indicated by series of parallel lines
starting from a distance of 6m from runway end.
 The threshold markings are in the form of stripes 3.60m wide,
spaced 0.90m clear and placed symmetrically on either side of
runway centre line.

32.  At some airports, it is desirable to displace the runway threshold
on a permanent basis.
 A displaced threshold is one which has been moved a certain
distance from the end of runway.
 The reason for displacing is due to presence of small obstruction
or water course near runway entrance in the direction of landing.
 It is usually adopted to clear obstructions in the flight path.

33. b) Touchdown or landing zone marking
 Runway touch down area is indicated by series of parallel strips
marked parallel to the centre line of runway.
 The number of strips decreases gradually in the direction of
landing.
 For normal landing, the pilot should be able to touch the runway
within the touch down area.

34. c) Runway Edge Strip Marking
 Runway edge strip marking is required when the runway-
pavement width is 45m or more.
 It consists of a long continuous strip 0.9m wide and placed near
the edges of runway.

36. d) Runway Centre Line Marking
 The centre-line of runway is represented by a broken strip
running along the entire length of runway.
 The width of the line is 90cm.
e)Runway Numbering
 Runway are numbered between 01 and 36 which is generally
magnetic azimuth of runway measured clockwise from north.

37.  The marking is given to
the nearest of 10o.
 In East-west runway, the
east end is marked 27 (for
270degree) and the west
end is marked 9 (for
90degree).

38. f) Two or more parallel runways
If there are two or more number of parallel runways, they
are marked as follows at the threshold
a) Two parallel runways : L, R
b) Three parallel runways: L, C, R
c) Four parallel runways : L, LC, RC, R

39. TAXIWAY MARKING:
 Taxiway markings are marked in yellow colour.
 The centre line is marked with single strip of 15cm width.
 This centre line normally terminates at runway edge except in
case of exit taxiway where it will curved in to centre line of
runway.

40.  At taxiway intersection, the centreline marking continues
through the intersection area.
 A Holding point marker should be painted at all intersection of
taxiway with the runways.
 The holding position should be at least 30m from the runway
edge.