Page 240 - Aeronautical Engineer Data Book

Airport design and compatibility 195
people-mover and embark or disembark in the
conventional manner (Stansted, UK, is an
example).

Unit terminals
The term unit terminal is used when an airport
passenger terminal system comprises more than
one terminal. Unit terminals may be made up of
a number of terminals of similar design (Dallas-
Fort Worth, USA), terminals of different design
(London Heathrow), terminals fulfilling differ­
ent functions (London Heathrow, Arlanda,
Stockholm), or terminals serving different
airlines (Paris Charles de Gaulle). The success­
ful operation of unit terminal airports requires
rapid and efficient automatic people-movers
that operate between the terminals.

11.1.8 The apron
An important requirement in the design of an
airport is minimizing the time needed to service
an aircraft after it has landed. This is especially
important in the handling of short-haul aircraft,
where unproductive ground time can consume an
unacceptably large percentage of flight time. The
turnaround time for a large passenger transport
between short-haul flights can be as little as 25
minutes. During this period, a large number of
service vehicles circulate on the apron (see Figure
10.5 in Chapter 10), so an important aspect of the
efficient operation of an airport facility is the
marshalling of ground service vehicles and aircraft
in the terminal apron area. Such an operation can
become extremely complex at some of the world’s
busiest international airports, where an aircraft
enters or leaves the terminal apron approximately
every 20 seconds.

11.1.9 Cargo facilities
Although only approximately 1–2% of world­
wide freight tonnage is carried by air, a large
international airport may handle more than one
million tons of cargo per year. Approximately
10% of air cargo is carried loose or in bulk, the