(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 provided the runway surface is appropriately
marked as usable runway (See FIG 4-3-6). The following examples clarify the intent of this paragraph.
REFERENCE-
AIM, Para 2-3-3, Runway Markings.
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 requirements 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.

4-3-10

Airport Operations