Page 218 - Aeronautical Engineer Data Book

174 Aeronautical Engineer’s Data Book
11.1.2 Airport site selection
The airport site selection process includes
several stages of activity. Table 11.1 shows the
main ‘first stage balance factors’.

Table 11.1 Airport site selection: ‘first stage balance factors’
Aeronautical requirements Environmental constraints

• Flat area of land (up to • Should not impinge on
3000* acres for a large areas of natural beauty
facility) • Sufficiently far away
• Sufficiently close to from urban centres to
population centres to minimize the adverse
allow passenger access effects of noise etc.
*Note: Some large international airports exceed this figure (e.g.
Jeddah, Saudi Arabia and Charles de Gaulle, Paris).

11.1.3 Operational requirements – ‘rules of thumb’
There is a large variation in the appearance and
layout of airport sites but all follow basic ‘rules
of thumb’:
• The location and orientation of the runways
are primarily decided by the requirement to
avoid obstacles during take-off and landing
procedures. 15 km is used as a nominal
‘design’ distance.
• Runway configuration is chosen so that they
will have manageable crosswind compo­
nents (for the types of aircraft being used)
for at least 95% of operational time.
• The number of runways available for use at
any moment determines the operational
capacity of the airport. Figure 11.1 shows
common runway layouts. Crosswind facility
is achieved by using either a ‘crossed’ or
‘open or closed vee’ layout.
• Operational capacity can be reduced under
IFR (Instrument Flying Rules) weather
conditions when it may not be permissible
to use some combinations of runways simul­
taneously unless there is sufficient separa­
tion (nominally 1500+ metres).