Runway End Siting RequirementsAC 150/5300-13 CHG 10
Appendix 2
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1. PURPOSE. This appendix contains guidance on
siting thresholds to meet approach obstacle clearance
requirements and departure obstacle clearance
requirements.
2. APPLICATION.
a. The threshold should be located at the beginning
of the full-strength runway pavement or runway surface.
However, displacement of the threshold may be required
when an object that obstructs the airspace required for
landing and/or departing airplanes is beyond the airport
owner's power to remove, relocate, or lower. Thresholds
may also be displaced for environmental considerations,
such as noise abatement, or to provide the standard RSA
and ROFA lengths.
b. When a hazard to air navigation exists, the amount
of displacement of the threshold or reduction of the TODA
should be based on the operational requirements of the
most demanding airplanes. The standards in this appendix
minimize the loss of operational use of the established
runway and reflect the FAA policy of maximum utilization
and retention of existing paved areas on airports.
c. Displacement of a threshold reduces the length of
runway available for landings. Depending on the reason
for displacement of the threshold, the portion of the runway
behind a displaced threshold may be available for takeoffs
in either direction and landings from the opposite direction.
Refer to Appendix 14, Declared Distances, for additional
information.
d. Where specifically noted, the Glidepath Angle
(GPA) and Threshold Crossing Height (TCH) of a
vertically guided approach may be altered (usually
increased) rather than displacing the threshold. Examples
of approaches with positive vertical guidance include
Instrument Landing System (ILS), Microwave Landing
System (NILS), Localizer Performance with Vertical
Guidance (LPV), Lateral Navigation/Vertical Navigation
(LNAV/VNAV), and required navigation performance
(RNP). Alternatively, a combination of threshold
displacement and altering of the Glidepath Angle/
Threshold Crossing Height (GPA/TCH) may also be
accomplished. Guidelines for maximum and minimum
values of TCH and GPA are contained in FAA Order
8260.3, United States Standard for Terminal Instrument
Procedures (TERPS). The tradeoff between threshold
displacement, TCH, and GPA is complex, but can be
analyzed by applying formula contained in the order.
Contact the appropriate FAA Airports Regional or
District Office for assistance on the specific requirements
and effects of GPA and TCH changes.
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a. These standards should not be interpreted as an
FAA blanket endorsement of the alternative to displace or
relocate a runway threshold. Threshold displacement or
relocation should be undertaken only after a full evaluation
reveals that displacement or relocation is the only practical
alternative.
b. The standards in this appendix are not applicable
for identifying objects affecting navigable airspace. See
Title 14 Code of Federal Regulations Part 77, Objects
Affecting Navigable Airspace.
a. Possible Actions. When a penetration to a
threshold siting surface defined in paragraph 5 exists, one
or more of the following actions are required:
(1) Approach Surfaces.
(a) The object is removed or lowered to
preclude penetration of applicable threshold siting surfaces;
(b) The threshold is displaced to preclude
object penetration of applicable threshold siting surfaces,
with a resulting shorter landing distance; or
(c) The GPA and/or TCH is/are modified,
or a combination of threshold displacement and
GPAITCH increase is accomplished.
(d) Visibility minimums are raised.
(e) Night operations are prohibited unless
the obstruction is lighted or an approved Visual Glide Slope
Indicator (VGSI) is used.
(2) Departure Surfaces for Designated
Runways._ The applicability of the surface defined in Table
A2-1 is dependant on the designation of primary
runway(s) for departure. The Airport Sponsor, through the
Airports District Office to the Regional Airspace
Procedures Team (RAPT), will identify runway end(s)
intended primarily for instrument departures. The
determination of primary runway(s) for departure does not
prohibit or negate the use of other runways. It only
identifies the applicability of the surface in Table A2-1 to
the runway end(s).
(a) Remove, relocate, or lower (or both
relocate and lower) the object to preclude penetration of
applicable siting surfaces unless it is fixed by function
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and/or designated impracticable. Within 6000' of the Table
A2-1 surface origin, objects less than or equal to an
elevation determined by application of the formula below
are allowable.
E + (0.025 x D)
Where:
E = DER elevation
D = Distance from OCS origin to object in feet
(b) Decrease the Takeoff Distance Available
(TODA) to preclude object penetration of applicable siting
surfaces, with a resulting shorter takeoff distance (the
Departure End of the Runway (DER) is coincident with the
end of the TODA where a clearway is not in effect); or
(c) Modify instrument departures. Contact the Flight
Procedures Office (FPO) for guidance. Objects penetrating
by < 35 feet may not require actions (a) or (b); however,
they will impact departure nummums/climb gradients or
departure procedures.
b. Relevant Factors for Evaluation.
(1) Types of airplanes that will use the runway
and their performance characteristics.
(2) Operational disadvantages associated with
accepting higher landing/ takeoff minimums.
(3) Cost of removing, relocating, or lowering the
object.
(4) Effect of the reduced available
landing/takeoff length when the runway is wet or icy.
(5) Cost of extending the runway if insufficient
runway length would remain as a result of displacing the
threshold. The environmental aspects of a runway
extension need to also be evaluated under this
consideration.
(6) Cost and feasibility of relocating visual and
electronic approach aids, such as threshold lights, visual
glide slope indicator, runway end identification lights,
localizer, glide slope (to provide a threshold crossing height
of not more than 60 feet (18 m)), approach lighting system,
and runway markings.
(7) Effect of the threshold change on noise
abatement.
5. CLEARANCE REQUIREMENTS. The standard
shape, dimensions, and slope of the surface used for
locating a threshold are dependent upon the type of aircraft
operations currently conducted or forecasted, the landing
AC 150/5300-13 CHG 10
Appendix 2
visibility minimums desired, and the types of
instrumentation available or planned for that runway end.
a. Approaches with Positive Vertical Guidance.
Table A2-1 and Figure A2-1 describe the clearance
surfaces required for instrument approach procedures
with vertical guidance.
The Glidepath Qualification Surface (GQS) limits the
height of obstructions between Decision Altitude (DA)
and runway threshold (RWT). When obstructions exceed
the height of the GQS, an approach procedure with
positive vertical guidance is not authorized. Further
information can be found in the appropriate TERPS
criterion.
b. Instrument Approach Procedures Aligned with
the Runway Centerline. Table A2-1 and Figure A2-1
describe the minimum clearance surfaces required for
instrument approach procedures aligned with the runway
centerline.
C. Procedures Not Aligned with the Runway
Centerline. To accommodate for offset procedures,
increase the lateral width at threshold by multiplying the
width specified in the appropriate paragraph by 2 (offset
side only). The outside offset boundary splays from this
point at an angle equal to the amount of angular divergence
between the final approach course and runway centerline +
10 degrees. Extend the outside offset boundary out to the
distance specified in the applicable paragraph and connect
it to runway centerline with an are of the same radius. On
the side opposite the offset, construct the area aligned with
runway centerline as indicated (non -offset side only). The
surface slope is as specified in the applicable paragraph,
according to Table A2-1. Figure A2-2 is an example of the
offset procedure.
d. Locating or Determining the DER The
standard shape, dimensions, and slope of the departure
surface used for determining the DER, as defined in
TERPS, is only dependent upon whether or not
instrument departures are being used or planned for that
runway end. See Table A2-1 and Figures A2-1 and A2-2
for dimensions.
Subparagraph 5d(2) applies only to runways supporting Air
Carrier departures and is not to be considered a clearance
surface.
(1) For Departure Ends at Designated
Runways.
(a) No object should penetrate a surface
beginning at the elevation of the runway at the DER or end
of clearway, and slopes at 40:1. Penetrations by existing
obstacles of 35 feet or less would not require TODA
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Appendix 2
reduction or other mitigations found in paragraph 4;
however, they may affect new or existing departure
procedures.
(2) Departure Runway Ends Supporting Air
Carrier Operations.
(a) Objects should be identified that
penetrate a one -engine inoperative (OEI) obstacle
identification surface (OIS) starting at the DER and at the
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elevation of the runway at that point, and slopes upward at
62.5:1. See Figure A24.
Note: This surface is provided for information only and
does not take effect until January 1, 2008.
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Appendix 2
DIMENSIONAL STANDARDS*
Slope/
Runway Type
Feet
OCS
A
B
C
ID
E
Approach end of runways expected to serve
I
small airplanes with approach speeds less than
0
60
150
500
2,500
15:1
50 knots. (Visual runways only, day/night)
Approach end of runways expected to serve
2
small airplanes with approach speeds of 50
0
125
350
2,250
2,750
20:1
knots or more. (Visual runways only,
day/night)
Approach end of runways expected to serve
3
large airplanes (Visual day/night); or
0
200
500
1,500
8,500
20:1
instrument minimums >_ 1 statute mile (day
onl .
Approach end of runways expected to support
200
200
1,700
10,000
0
20:1
4
instrument night circling. 1
Approach end of runways expected to support
200
200
1,900
10,0002
0
20:1
5
instrument straight in night operations, serving
approach category A and B aircraft only. 1
Approach end of runways expected to support
200
400
1,900
10,0002
0
20:1
6
instrument straight in night operations serving
greater than approach category B aircraft. 1
7 3'
Approach end of runways expected to
0
%2 width
760
10,000 Z
0
30:1
6' 7'
accommodate approaches with positive vertical
runway
8
guidance (GQS).
+ 100
Approach end of runways expected to
200
400
1,900
10,0002
0
20:1
8
accommodate instrument approaches having
visibility minimums >_ 3/4 but < 1 statute mile,
day or night.
Approach end of runways expected to
200
400
1,900
10,0002
0
34:1
accommodate instrument approaches having
9
visibility minimums < 3/4 statute mile or
precision approach (ILS, GLS, or MLS), day or
night.
10
Approach runway ends having Category H
The criteria are set forth in TERPS, Order 8260.3.
approach minimums or greater.
1 F
Departure runway ends for all instr anent
0 4
See Figure A2-3
40:1
operations.
12
Departure runway ends supporting Air Carrier
0 4
See Figure A2-4
62.5:1
operations.
* The letters are keyed to those shown in Figure A2-1.
Notes:
1. Lighting of obstacle penetrations to this surface or the use of a VGSI, as defined by the TERPS order, may avoid
displacing the threshold.
2. 10,000 feet is a nominal value for planning purposes. The actual length of these areas is dependent upon the visual
descent point position for 20:1 and 34:1 and Decision Altitude point for the 30:1.
3. Any penetration to this surface will limit the runway end to nonprecision approaches. No vertical approaches will be
authorized until the penetration(s) is/are removed except obstacles fixed by function and/or allowable grading.
4. Dimension A is measured relative to Departure End of Runway (DER) or TODA (to include clearway).
5. Data Collected regarding penetrations to this surface are provided for information and use by the air carriers
operating from the airport. These requirements do not take effect until January 1, 2008.
6. Surface dimensions/Obstacle Clearance Surface (OCS) slope represent a nominal approach with 3 degree GPA, 50'
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TCH, < 500' HAT. For specific cases refer to TERPS. The Obstacle Clearance Surface slope (30:1) represents a
nominal approach of 3 degrees (also known as the Glide Path Angle). This assumes a threshold crossing height of
50 feet. Three degrees is commonly used for ILS systems and VGSI aiming angles. This approximates a 30:1
approach angle that is between the 34:1 and the 20:1 notice surfaces of Part 77. Surfaces cleared to 34:1 should
accommodate a 30:1 approach without any obstacle clearance problems.
7. For runways with vertically guided approaches the criteria in Row 7 is in addition to the basic criteria established
within the table, to ensure the protection of the Glidepath Qualification Surface.
8. For planning purposes, sponsors and consultants determine a tentative Decision Altitude based on a 3° Glidepath
angle and a 50-foot Threshold Crossing Height.
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SURFP
AT EN[
WAY IF
PLACE
f
1,000 FEET J-
500 FEET
STARTS AT
DEPARTURE END
OF RUNWAY (DER)
10,200 FEET
TERPS (40:1)
�► — 10,200 FEET
AC 150/5300-13 CHG 10
Appendix 2
Figure A2-3. Departure surface for Instrument Runways TERPS (40:1)
* This is an interpretation of the application of the TERPS surface associated with a clearway.
3,233 FEET
3,233 FEET
-did_
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