AIM

4/3/14

4−3−8

Airport Operations

Zone (RPZ) may reduce a runway’s declared

distances to less than the physical length of the

runway at geographically constrained airports (See

FIG 4−3−5). 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 provided the runway surface is appropri-

ately marked as usable runway (See FIG 4−3−5). The

following examples clarify the intent of this

paragraph.

REFERENCE

−

AIM, Runway Markings, Paragraph 2

−3−3.

AC 150/5340

−1, Standards for Airport Markings.

EXAMPLE

−

1. The declared LDA for runway 9 must be used when
showing compliance with the landing distance require-
ments of the applicable airplane operating rules and/or
airplane operating limitations or when making a before
landing performance assessment. The LDA is less than the
physical runway length, not only because of the displaced
threshold, but also because of the subtractions necessary
to meet the RSA beyond the far end of the runway. However,
during the actual landing operation, it is permissible for
the airplane to roll beyond the unmarked end of the LDA.

2. The declared ASDA for runway 9 must be used when
showing compliance with the accelerate

−stop distance

requirements of the applicable airplane operating rules
and/or airplane operating limitations. The ASDA is less
than the physical length of the runway due to subtractions
necessary to achieve the full RSA requirement. However, in
the event of an aborted takeoff, it is permissible for the
airplane to roll beyond the unmarked end of the ASDA as
it is brought to a full

−stop on the remaining usable runway.