Section 77.23

14 CFR Ch. I (1-1-19 Edition)

runway centerline extended, beginning
200 feet beyond each end of the primary
surface at the centerline elevation of
the runway end and extending for 50,000
feet. The slope of the approach clearance surface is 50 to 1 along the runway
centerline extended until it reaches an
elevation of 500 feet above the established airport elevation. It then continues horizontally at this elevation to
a point 50,000 feet from the point of beginning. The width of this surface at
the runway end is the same as the primary surface, it flares uniformly, and
the width at 50,000 is 16,000 feet.
(4) Transitional surfaces. These surfaces connect the primary surfaces, the
first 200 feet of the clear zone surfaces,
and the approach clearance surfaces to
the inner horizontal surface, conical
surface, outer horizontal surface or
other transitional surfaces. The slope
of the transitional surface is 7 to 1 outward and upward at right angles to the
runway centerline.
Section 77.23 Heliport imaginary surfaces.
(a) Primary surface. The area of the
primary surface coincides in size and
shape with the designated take-off and
landing area. This surface is a horizontal plane at the elevation of the established heliport elevation.
(b) Approach surface. The approach
surface begins at each end of the heliport primary surface with the same
width as the primary surface, and extends outward and upward for a horizontal distance of 4,000 feet where its
width is 500 feet. The slope of the approach surface is 8 to 1 for civil heliports and 10 to 1 for military heliports.
(c) Transitional surfaces. These surfaces extend outward and upward from
the lateral boundaries of the primary
surface and from the approach surfaces
at a slope of 2 to 1 for a distance of 250
feet measured horizontally from the
centerline of the primary and approach
surfaces.

kpayne on VMOFRWIN702 with $$_JOB

Subpart D - Aeronautical Studies
and Determinations
Section 77.25 Applicability.
(a) This subpart applies to any aeronautical study of a proposed construction or alteration for which notice to
the FAA is required under Section 77.9.

(b) The purpose of an aeronautical
study is to determine whether the
aeronautical effects of the specific proposal and, where appropriate, the cumulative impact resulting from the
proposed construction or alteration
when combined with the effects of
other existing or proposed structures,
would constitute a hazard to air navigation.
(c) The obstruction standards in subpart C of this part are supplemented by
other manuals and directives used in
determining the effect on the navigable
airspace of a proposed construction or
alteration. When the FAA needs additional information, it may circulate a
study to interested parties for comment.
Section 77.27 Initiation of studies.
The FAA will conduct an aeronautical study when:
(a) Requested by the sponsor of any
proposed construction or alteration for
which a notice is submitted; or
(b) The FAA determines a study is
necessary.
Section 77.29 Evaluating aeronautical effect.
(a) The FAA conducts an aeronautical study to determine the impact
of a proposed structure, an existing
structure that has not yet been studied
by the FAA, or an alteration of an existing structure on aeronautical operations, procedures, and the safety of
flight. These studies include evaluating:
(1) The impact on arrival, departure,
and en route procedures for aircraft operating under visual flight rules;
(2) The impact on arrival, departure,
and en route procedures for aircraft operating under instrument flight rules;
(3) The impact on existing and
planned public use airports;
(4) Airport traffic capacity of existing public use airports and public use
airport development plans received before the issuance of the final determination;
(5) Minimum obstacle clearance altitudes, minimum instrument flight
rules altitudes, approved or planned instrument approach procedures, and departure procedures;
(6) The potential effect on ATC radar,
direction finders, ATC tower line-of-

700

VerDate Sep<11>2014

16:30 Jun 25, 2019

Jkt 247047

PO 00000

Frm 00710

Fmt 8010

Sfmt 8010

Q:\14\14V2.TXT

PC31