Page 107 - Planning and Design of Airports

Air craft Characteristics Related to Airport Design 77

to land. These speeds are defined in aircraft performance manuals as
V-speeds. Such V-speeds include:

V : Do-Not-Exceed Speed, the fastest an aircraft may cruise in
ne
smooth air to maintain safe structural integrity.
V : Design Maneuvering Speed, the recommended speed for an
a
aircraft performing maneuvers (such as turns) or operating in
turbulent air.
V : Liftoff Speed, the recommended speed at which the aircraft
lo
can safely liftoff.
V: Rotate Speed, the recommended speed at which the nose wheel
r
may be lifted off the runway during takeoff.
V : Decision Speed, the speed at which, during a takeoff run, the
1
pilot decides to continue with the takeoff, even if there might be
an engine failure from this point before takeoff. If an aircraft devel-
ops an engine issue prior to reaching V , the pilot will abort the
1
takeoff.
V : Stall Speed (landing confi guration), the minimum possible
so
speed for an aircraft in landing configuration (landing gear down,

flaps extended) to maintain lift. If the aircraft’s airspeed goes
below V , the airplane loses all lift and is said to stall. This speed
so
is also typically the speed at which an aircraft will touch down on
a runway during landing.
V : Reference Landing Approach Speed, the speed at which an
ref
aircraft travels when on approach to landing. V is typically cal-
ref
culated as 1.3 × V .
so
For airport planning and design, many of these speeds contrib-
ute to determining required runway lengths for takeoff and landing,
as well as in determining the maximum number of operations (i.e.,
the capacity) that can be performed on runways over a given period
of time.

Payload and Range
The maximum distance that an aircraft can fly, given a certain level of
fuel in the tanks is known as the aircraft’s range. There are a number
of factors that influence the range of an aircraft, among the most
important is payload. Normally as the range is increased the payload
is decreased, a weight trade-off occurring between fuel to fly to the
destination and the payload which can be carried.
The relationship between payload and range is illustrated in
Fig. 2-8. The point A, the range at maximum payload, designates the
farthest distance, R , that an aircraft can fly with a maximum struc-
a
tural payload. To fly a distance of R and carry a payload of P the air-
a a
craft has to take off at its maximum structural takeoff weight; however,
its fuel tanks are not completely filled. Point B, the range at maximum