(1) Takeoff Run Available (TORA) " The
runway length declared available and suitable for
the ground run of an airplane taking off.
The TORA is typically the physical length of the
runway, but it may be shorter than the runway length
if necessary to satisfy runway design standards. For
example, the TORA may be shorter than the runway
length if a portion of the runway must be used to
satisfy runway protection zone requirements.
(2) Takeoff Distance Available (TODA) "
The takeoff run available plus the length of any
remaining runway or clearway beyond the far end of
the takeoff run available.
The TODA is the distance declared available for
satisfying takeoff distance requirements for airplanes
where the certification and operating rules and
available performance datllow for the consideration of a clearway in takeoff performance
computations.
NOTE-
The length of any available clearway will be included in the
TODA published in the entry for that runway end within the
Chart Supplement U.S.

(3) Accelerate-Stop Distance Available
(ASDA) " The runway plus stopway length declared
available and suitable for the acceleration and
deceleration of an airplane aborting a takeoff.
The ASDA may be longer than the physical length of
the runway when a stopway has been designated
available by the airport operator, or it may be shorter
than the physical length of the runway if necessary to
use a portion of the runway to satisfy runway design
standards; for example, where the airport operator
uses a portion of the runway to achieve the runway
safety area requirement. ASDA is the distance used
to satisfy the airplane accelerate-stop distance
performance requirements where the certification
and operating rules require accelerate-stop distance
computations.
NOTE-
The length of any available stopway will be included in the
ASDA published in the entry for that runway end within the
Chart Supplement U.S.

(4) Landing Distance Available (LDA) -
The runway length declared available and suitable
for a landing airplane.

Airport Operations

The LDA may be less than the physical length of the
runway or the length of the runway remaining beyond
a displaced threshold if necessary to satisfy runway
design standards;for example, where the airport
operator uses a portion of the runway to achieve the
runway safety area requirement.
Although some runway elements (such as stopway
length and clearway length) may be available
information, pilots must use the declared distances
determined by the airport operator and not attempt to
independently calculate declared distances by
adding those elements to the reported physical
length of the runway.
(b) The airplane operating rules and/or the
airplane operating limitations establish minimum
distance requirements for takeoff and landing and
are based on performance data supplied in the
Airplane Flight Manual or Pilot"s Operating
Handbook. The minimum distances required for
takeoff and landing obtained either in planning
prior to takeoff or in performance assessments
conducted at the time of landing must fall within the
applicable declared distances before the pilot can
accept that runway for takeoff or landing.
(c) Runway design standards may impose
restrictions on the amount of runway available for
use in takeoff and landing that are not apparent
from the reported physical length of the runway or
from runway markings and lighting. The runway
elements of Runway Safety Area (RSA), Runway
Object Free Area (ROFA), and Runway Protection
Zone (RPZ) may reduce a runway"s declared
distances to less than the physical length of the
runway at geographically constrained airports (See
FIG 4-3-6). When considering the amount of
runway available for use in takeoff or landing
performance calculations, the declared distances
published for a runway must always be used in lieu
of the runway"s physical length.
REFERENCE-
AC 150/5300-13, Airport Design

(d) While some runway elements associated
with declared distances may be identifiable through
runway markings or lighting (for example, a
displaced threshold or a stopway), the individual
declared distance limits are not marked or otherwise
identified on the runway. An aircraft is not prohibited
from operating beyond a declared distance limit
during the takeoff, landing, or taxi operation

4-3-9