Taxiway Design | Transportation Engineering - Civil Engineering (CE) PDF Download

 Page 1


TAXIWAY DESIGN
The design of the taxiway system is determined by the volume of air traf?c, the runway
con?guration, and the location of the terminal building and other ground facilities. The
ICAO (1, 13) and the FAA (1) have published general guidelines for taxiway layout
and design, which are summarized below.
Taxiway routes should be direct, straight, and uncomplicated. Where curves cannot
be avoided, their radii should be large enough to permit taxiing speeds on the order of
20–30 mph. Radii corresponding to taxiing speeds of 20, 30, and 40 mph are, respec-
tively, 200, 450, and 800 ft. The taxiway pavement should be widened on curves and at
intersections to lessen the likelihood of an aircraft’s wheels dropping off the pavement.
Table 8.13 shows recommended taxiway edge safety margins, the minimum distance
between the outside of the airplane wheels and the pavement edge. The dimensions
given in Table 8.17 are suitable for the design of taxiway ?llets at intersections, entrance
taxiways, and other areas where low-speed movements are anticipated. These stan-
dards should give adequate taxiway edge safety margins for the aircraft in each design
group. The symbols for these dimensions are keyed to those shown in Figure 8.16.
Where these standard ?llet designs are not appropriate (e.g., because of space limita-
tions or because a particular type of airplane does not have the minimum taxiway edge
safety margin), the pavement ?llet may be custom designed using equations given in
reference 1.
The minimum separations between centerlines of parallel taxiways are based on a
minimum wing tip clearance of 0.2 times the wingspan of the most demanding airplane
plus a 10-ft (3-m) margin of safety (1). The same wing tip clearance is recommended
for taxiway-to-obstacle separation (13). In the immediate terminal area where taxiing is
Table 8.17 Taxiway Fillet Dimensions
Airplane design group
Design item Dimension
a
I II III
b
IVVVI
Radius of taxiway turn (ft)
c
R 75 75 100 150 150 170
Length of lead-in to ?llet (ft) L 50 50 150 250 250 250
Fillet radius for judgmental oversteering
symmetrical widening (ft)
F 62.5 57.5 68 105 105 110
Fillet radius for judgmental oversteering
one side widening (ft)
F 62.5 57.5 60 97 97 100
Fillet radius for tracking centerline (ft) F 60 55 55 85 85 85
a
Letters are keyed to those shown as dimension on Figure 8.9.
b
Airplane design group III with a wheelbase equal to or greater than 60 ft, should use a ?llet radius of 50 ft.
c
ft = 0.3048 m.
Page 2


TAXIWAY DESIGN
The design of the taxiway system is determined by the volume of air traf?c, the runway
con?guration, and the location of the terminal building and other ground facilities. The
ICAO (1, 13) and the FAA (1) have published general guidelines for taxiway layout
and design, which are summarized below.
Taxiway routes should be direct, straight, and uncomplicated. Where curves cannot
be avoided, their radii should be large enough to permit taxiing speeds on the order of
20–30 mph. Radii corresponding to taxiing speeds of 20, 30, and 40 mph are, respec-
tively, 200, 450, and 800 ft. The taxiway pavement should be widened on curves and at
intersections to lessen the likelihood of an aircraft’s wheels dropping off the pavement.
Table 8.13 shows recommended taxiway edge safety margins, the minimum distance
between the outside of the airplane wheels and the pavement edge. The dimensions
given in Table 8.17 are suitable for the design of taxiway ?llets at intersections, entrance
taxiways, and other areas where low-speed movements are anticipated. These stan-
dards should give adequate taxiway edge safety margins for the aircraft in each design
group. The symbols for these dimensions are keyed to those shown in Figure 8.16.
Where these standard ?llet designs are not appropriate (e.g., because of space limita-
tions or because a particular type of airplane does not have the minimum taxiway edge
safety margin), the pavement ?llet may be custom designed using equations given in
reference 1.
The minimum separations between centerlines of parallel taxiways are based on a
minimum wing tip clearance of 0.2 times the wingspan of the most demanding airplane
plus a 10-ft (3-m) margin of safety (1). The same wing tip clearance is recommended
for taxiway-to-obstacle separation (13). In the immediate terminal area where taxiing is
Table 8.17 Taxiway Fillet Dimensions
Airplane design group
Design item Dimension
a
I II III
b
IVVVI
Radius of taxiway turn (ft)
c
R 75 75 100 150 150 170
Length of lead-in to ?llet (ft) L 50 50 150 250 250 250
Fillet radius for judgmental oversteering
symmetrical widening (ft)
F 62.5 57.5 68 105 105 110
Fillet radius for judgmental oversteering
one side widening (ft)
F 62.5 57.5 60 97 97 100
Fillet radius for tracking centerline (ft) F 60 55 55 85 85 85
a
Letters are keyed to those shown as dimension on Figure 8.9.
b
Airplane design group III with a wheelbase equal to or greater than 60 ft, should use a ?llet radius of 50 ft.
c
ft = 0.3048 m.
W
L
W
W
L
L
W
W
L
R
F
F
R
F
TAXIWAY
TAXIWAY
L
+
+ +
+
+
+
C
L
C
L
C
W
L
L R
Figure 8.16 Typical taxiway intersection details (1).
accomplished at slow speeds and with special guidance procedures and devices, a wing
tip clearance of 0.1 times the wingspan plus the margin of safety is recommended.
Assuming these wing tip clearances, the required separations, expressed in feet, for
taxiway design become:
Taxiway centerline to taxiway centerline: 1.2W + 10
Taxiway centerline to obstacle: 0.7W + 10
Taxiway centerline to obstacle in terminal area: 0.6W + 10
where W = wingspan of the most demanding aircraft, ft
In most instances, the clearance and separation distances given in Table 8.13 will
satisfy the minimum wing tip clearances. However, at high-density airports where
higher taxiing speeds are desired, larger clearances and separations should be used.
Page 3


TAXIWAY DESIGN
The design of the taxiway system is determined by the volume of air traf?c, the runway
con?guration, and the location of the terminal building and other ground facilities. The
ICAO (1, 13) and the FAA (1) have published general guidelines for taxiway layout
and design, which are summarized below.
Taxiway routes should be direct, straight, and uncomplicated. Where curves cannot
be avoided, their radii should be large enough to permit taxiing speeds on the order of
20–30 mph. Radii corresponding to taxiing speeds of 20, 30, and 40 mph are, respec-
tively, 200, 450, and 800 ft. The taxiway pavement should be widened on curves and at
intersections to lessen the likelihood of an aircraft’s wheels dropping off the pavement.
Table 8.13 shows recommended taxiway edge safety margins, the minimum distance
between the outside of the airplane wheels and the pavement edge. The dimensions
given in Table 8.17 are suitable for the design of taxiway ?llets at intersections, entrance
taxiways, and other areas where low-speed movements are anticipated. These stan-
dards should give adequate taxiway edge safety margins for the aircraft in each design
group. The symbols for these dimensions are keyed to those shown in Figure 8.16.
Where these standard ?llet designs are not appropriate (e.g., because of space limita-
tions or because a particular type of airplane does not have the minimum taxiway edge
safety margin), the pavement ?llet may be custom designed using equations given in
reference 1.
The minimum separations between centerlines of parallel taxiways are based on a
minimum wing tip clearance of 0.2 times the wingspan of the most demanding airplane
plus a 10-ft (3-m) margin of safety (1). The same wing tip clearance is recommended
for taxiway-to-obstacle separation (13). In the immediate terminal area where taxiing is
Table 8.17 Taxiway Fillet Dimensions
Airplane design group
Design item Dimension
a
I II III
b
IVVVI
Radius of taxiway turn (ft)
c
R 75 75 100 150 150 170
Length of lead-in to ?llet (ft) L 50 50 150 250 250 250
Fillet radius for judgmental oversteering
symmetrical widening (ft)
F 62.5 57.5 68 105 105 110
Fillet radius for judgmental oversteering
one side widening (ft)
F 62.5 57.5 60 97 97 100
Fillet radius for tracking centerline (ft) F 60 55 55 85 85 85
a
Letters are keyed to those shown as dimension on Figure 8.9.
b
Airplane design group III with a wheelbase equal to or greater than 60 ft, should use a ?llet radius of 50 ft.
c
ft = 0.3048 m.
W
L
W
W
L
L
W
W
L
R
F
F
R
F
TAXIWAY
TAXIWAY
L
+
+ +
+
+
+
C
L
C
L
C
W
L
L R
Figure 8.16 Typical taxiway intersection details (1).
accomplished at slow speeds and with special guidance procedures and devices, a wing
tip clearance of 0.1 times the wingspan plus the margin of safety is recommended.
Assuming these wing tip clearances, the required separations, expressed in feet, for
taxiway design become:
Taxiway centerline to taxiway centerline: 1.2W + 10
Taxiway centerline to obstacle: 0.7W + 10
Taxiway centerline to obstacle in terminal area: 0.6W + 10
where W = wingspan of the most demanding aircraft, ft
In most instances, the clearance and separation distances given in Table 8.13 will
satisfy the minimum wing tip clearances. However, at high-density airports where
higher taxiing speeds are desired, larger clearances and separations should be used.
At large and busy airports, the time an average aircraft occupies the runway fre-
quently determines the capacity of the runway system and the airport as a whole. This
indicates that exit taxiways should be conveniently located so that landing aircraft can
vacate the runway as soon as possible.
Figure 8.17 illustrates three common types of exit taxiways. Perpendicular exit
taxiways may be used when the design peak-hour traf?c is less than 30 operations per
hour. To expedite the movement of landing aircraft from the runway, most modern
air carrier airports provide exit taxiways that are oriented at an angle to the runway
centerline. The exit taxiway angled 45
?
to the runway centerline is recommended for
small aircraft. It will accommodate an exit speed of 40 mph. The exit con?guration in
Figure 8.17 (30
?
angle of intersection) permits runway turnoff speeds up to 60 mph.
The number and location of exit taxiways depend on the type and mix of aircraft
using the runway. At utility airports, three exit taxiways are generally suf?cient: one at
the center and one at each end of the runway. A modern air carrier runway may have
three angled exit taxiways for each landing direction plus several 90
?
exit taxiways.
For a given class of aircraft, the desired location of a high-speed exit taxiway can
be calculated based on the following design factors:
1. Distance from the threshold to touchdown
2. Touchdown speed
3. Initial exit speed (turnoff speed at the point of curvature) (PC)
4. Rate of deceleration
Other planning factors include location of the terminal/apron area, location of
other runways and their exits, optimization of traf?c ?ow in the operational area, and
avoidance of unnecessary taxi detours (1).
The distance from the threshold to touchdown averages about 1500 ft for turbojet
aircraft (categories C and D)
*
and approximately 1000 ft for other aircraft (category
B). Typical touchdown speeds are 164, 202, and 237 ft/sec, respectively, for category
B, C, and D aircraft.
Initial exit speeds are generally taken to be 40 mph (59 ft/sec) for small aircraft
and 60 mph (88 ft/sec) for large aircraft with a deceleration rate of 5 ft/sec
2
(1). The
ICAO recommends a deceleration rate of 1.25 m/sec
2
(4.1 ft/sec
2
) for computing the
location of exit taxiways (13).
Using its own classi?cation, the ICAO groups aircraft according to their threshold
speeds:
Group A Less than 169 km/hr (91 knots)
Group B Between 169 km/hr (91 knots) and 222 km/hr (120 knots)
Group C Between 223 km/hr (121 knots) and 259 km/hr (140 knots)
Group D Between 261 km/hr (141 knots) and 306 km/hr (165 knots)
*
The categories here refer to groupings of airplanes in U.S. Standard for Terminal Instrument Procedures
(TERPS). These categories, which are made on the basis of approach speed and maximum landing weight,
should not be confused with those mentioned in Section 6-4 for the ICAO categories designated by the
same letters.
Page 4


TAXIWAY DESIGN
The design of the taxiway system is determined by the volume of air traf?c, the runway
con?guration, and the location of the terminal building and other ground facilities. The
ICAO (1, 13) and the FAA (1) have published general guidelines for taxiway layout
and design, which are summarized below.
Taxiway routes should be direct, straight, and uncomplicated. Where curves cannot
be avoided, their radii should be large enough to permit taxiing speeds on the order of
20–30 mph. Radii corresponding to taxiing speeds of 20, 30, and 40 mph are, respec-
tively, 200, 450, and 800 ft. The taxiway pavement should be widened on curves and at
intersections to lessen the likelihood of an aircraft’s wheels dropping off the pavement.
Table 8.13 shows recommended taxiway edge safety margins, the minimum distance
between the outside of the airplane wheels and the pavement edge. The dimensions
given in Table 8.17 are suitable for the design of taxiway ?llets at intersections, entrance
taxiways, and other areas where low-speed movements are anticipated. These stan-
dards should give adequate taxiway edge safety margins for the aircraft in each design
group. The symbols for these dimensions are keyed to those shown in Figure 8.16.
Where these standard ?llet designs are not appropriate (e.g., because of space limita-
tions or because a particular type of airplane does not have the minimum taxiway edge
safety margin), the pavement ?llet may be custom designed using equations given in
reference 1.
The minimum separations between centerlines of parallel taxiways are based on a
minimum wing tip clearance of 0.2 times the wingspan of the most demanding airplane
plus a 10-ft (3-m) margin of safety (1). The same wing tip clearance is recommended
for taxiway-to-obstacle separation (13). In the immediate terminal area where taxiing is
Table 8.17 Taxiway Fillet Dimensions
Airplane design group
Design item Dimension
a
I II III
b
IVVVI
Radius of taxiway turn (ft)
c
R 75 75 100 150 150 170
Length of lead-in to ?llet (ft) L 50 50 150 250 250 250
Fillet radius for judgmental oversteering
symmetrical widening (ft)
F 62.5 57.5 68 105 105 110
Fillet radius for judgmental oversteering
one side widening (ft)
F 62.5 57.5 60 97 97 100
Fillet radius for tracking centerline (ft) F 60 55 55 85 85 85
a
Letters are keyed to those shown as dimension on Figure 8.9.
b
Airplane design group III with a wheelbase equal to or greater than 60 ft, should use a ?llet radius of 50 ft.
c
ft = 0.3048 m.
W
L
W
W
L
L
W
W
L
R
F
F
R
F
TAXIWAY
TAXIWAY
L
+
+ +
+
+
+
C
L
C
L
C
W
L
L R
Figure 8.16 Typical taxiway intersection details (1).
accomplished at slow speeds and with special guidance procedures and devices, a wing
tip clearance of 0.1 times the wingspan plus the margin of safety is recommended.
Assuming these wing tip clearances, the required separations, expressed in feet, for
taxiway design become:
Taxiway centerline to taxiway centerline: 1.2W + 10
Taxiway centerline to obstacle: 0.7W + 10
Taxiway centerline to obstacle in terminal area: 0.6W + 10
where W = wingspan of the most demanding aircraft, ft
In most instances, the clearance and separation distances given in Table 8.13 will
satisfy the minimum wing tip clearances. However, at high-density airports where
higher taxiing speeds are desired, larger clearances and separations should be used.
At large and busy airports, the time an average aircraft occupies the runway fre-
quently determines the capacity of the runway system and the airport as a whole. This
indicates that exit taxiways should be conveniently located so that landing aircraft can
vacate the runway as soon as possible.
Figure 8.17 illustrates three common types of exit taxiways. Perpendicular exit
taxiways may be used when the design peak-hour traf?c is less than 30 operations per
hour. To expedite the movement of landing aircraft from the runway, most modern
air carrier airports provide exit taxiways that are oriented at an angle to the runway
centerline. The exit taxiway angled 45
?
to the runway centerline is recommended for
small aircraft. It will accommodate an exit speed of 40 mph. The exit con?guration in
Figure 8.17 (30
?
angle of intersection) permits runway turnoff speeds up to 60 mph.
The number and location of exit taxiways depend on the type and mix of aircraft
using the runway. At utility airports, three exit taxiways are generally suf?cient: one at
the center and one at each end of the runway. A modern air carrier runway may have
three angled exit taxiways for each landing direction plus several 90
?
exit taxiways.
For a given class of aircraft, the desired location of a high-speed exit taxiway can
be calculated based on the following design factors:
1. Distance from the threshold to touchdown
2. Touchdown speed
3. Initial exit speed (turnoff speed at the point of curvature) (PC)
4. Rate of deceleration
Other planning factors include location of the terminal/apron area, location of
other runways and their exits, optimization of traf?c ?ow in the operational area, and
avoidance of unnecessary taxi detours (1).
The distance from the threshold to touchdown averages about 1500 ft for turbojet
aircraft (categories C and D)
*
and approximately 1000 ft for other aircraft (category
B). Typical touchdown speeds are 164, 202, and 237 ft/sec, respectively, for category
B, C, and D aircraft.
Initial exit speeds are generally taken to be 40 mph (59 ft/sec) for small aircraft
and 60 mph (88 ft/sec) for large aircraft with a deceleration rate of 5 ft/sec
2
(1). The
ICAO recommends a deceleration rate of 1.25 m/sec
2
(4.1 ft/sec
2
) for computing the
location of exit taxiways (13).
Using its own classi?cation, the ICAO groups aircraft according to their threshold
speeds:
Group A Less than 169 km/hr (91 knots)
Group B Between 169 km/hr (91 knots) and 222 km/hr (120 knots)
Group C Between 223 km/hr (121 knots) and 259 km/hr (140 knots)
Group D Between 261 km/hr (141 knots) and 306 km/hr (165 knots)
*
The categories here refer to groupings of airplanes in U.S. Standard for Terminal Instrument Procedures
(TERPS). These categories, which are made on the basis of approach speed and maximum landing weight,
should not be confused with those mentioned in Section 6-4 for the ICAO categories designated by the
same letters.
TAXIWAY
RUNWAY
50' R
200'
3'
P.C.
120' R
100' R
40'
25' R
C
L
C
L
600'
800'
45°
250'
200'
3'
250' R.
MIN.
150' R. FOR 200' R/W
175' R. FOR 150' R/W
R
MIN.
W
T
S
R
MIN.
P.C.
W
C
W
C
TAXIWAY
C
L
RUNWAY C
L
RUNWAY
TRAFFIC FLOW
C
L
TAXIWAY
25'R (7.5M)
25'R (7.5M)
800'R (250M)
30°
C
L
(a)
(b)
(c)
Figure 8.17 Common types of exit taxiways: (a) angled exit taxiway for small airplanes;
(b) 90
?
exit taxiway; (c) angled exit taxiway for large airplanes (13).
Page 5


TAXIWAY DESIGN
The design of the taxiway system is determined by the volume of air traf?c, the runway
con?guration, and the location of the terminal building and other ground facilities. The
ICAO (1, 13) and the FAA (1) have published general guidelines for taxiway layout
and design, which are summarized below.
Taxiway routes should be direct, straight, and uncomplicated. Where curves cannot
be avoided, their radii should be large enough to permit taxiing speeds on the order of
20–30 mph. Radii corresponding to taxiing speeds of 20, 30, and 40 mph are, respec-
tively, 200, 450, and 800 ft. The taxiway pavement should be widened on curves and at
intersections to lessen the likelihood of an aircraft’s wheels dropping off the pavement.
Table 8.13 shows recommended taxiway edge safety margins, the minimum distance
between the outside of the airplane wheels and the pavement edge. The dimensions
given in Table 8.17 are suitable for the design of taxiway ?llets at intersections, entrance
taxiways, and other areas where low-speed movements are anticipated. These stan-
dards should give adequate taxiway edge safety margins for the aircraft in each design
group. The symbols for these dimensions are keyed to those shown in Figure 8.16.
Where these standard ?llet designs are not appropriate (e.g., because of space limita-
tions or because a particular type of airplane does not have the minimum taxiway edge
safety margin), the pavement ?llet may be custom designed using equations given in
reference 1.
The minimum separations between centerlines of parallel taxiways are based on a
minimum wing tip clearance of 0.2 times the wingspan of the most demanding airplane
plus a 10-ft (3-m) margin of safety (1). The same wing tip clearance is recommended
for taxiway-to-obstacle separation (13). In the immediate terminal area where taxiing is
Table 8.17 Taxiway Fillet Dimensions
Airplane design group
Design item Dimension
a
I II III
b
IVVVI
Radius of taxiway turn (ft)
c
R 75 75 100 150 150 170
Length of lead-in to ?llet (ft) L 50 50 150 250 250 250
Fillet radius for judgmental oversteering
symmetrical widening (ft)
F 62.5 57.5 68 105 105 110
Fillet radius for judgmental oversteering
one side widening (ft)
F 62.5 57.5 60 97 97 100
Fillet radius for tracking centerline (ft) F 60 55 55 85 85 85
a
Letters are keyed to those shown as dimension on Figure 8.9.
b
Airplane design group III with a wheelbase equal to or greater than 60 ft, should use a ?llet radius of 50 ft.
c
ft = 0.3048 m.
W
L
W
W
L
L
W
W
L
R
F
F
R
F
TAXIWAY
TAXIWAY
L
+
+ +
+
+
+
C
L
C
L
C
W
L
L R
Figure 8.16 Typical taxiway intersection details (1).
accomplished at slow speeds and with special guidance procedures and devices, a wing
tip clearance of 0.1 times the wingspan plus the margin of safety is recommended.
Assuming these wing tip clearances, the required separations, expressed in feet, for
taxiway design become:
Taxiway centerline to taxiway centerline: 1.2W + 10
Taxiway centerline to obstacle: 0.7W + 10
Taxiway centerline to obstacle in terminal area: 0.6W + 10
where W = wingspan of the most demanding aircraft, ft
In most instances, the clearance and separation distances given in Table 8.13 will
satisfy the minimum wing tip clearances. However, at high-density airports where
higher taxiing speeds are desired, larger clearances and separations should be used.
At large and busy airports, the time an average aircraft occupies the runway fre-
quently determines the capacity of the runway system and the airport as a whole. This
indicates that exit taxiways should be conveniently located so that landing aircraft can
vacate the runway as soon as possible.
Figure 8.17 illustrates three common types of exit taxiways. Perpendicular exit
taxiways may be used when the design peak-hour traf?c is less than 30 operations per
hour. To expedite the movement of landing aircraft from the runway, most modern
air carrier airports provide exit taxiways that are oriented at an angle to the runway
centerline. The exit taxiway angled 45
?
to the runway centerline is recommended for
small aircraft. It will accommodate an exit speed of 40 mph. The exit con?guration in
Figure 8.17 (30
?
angle of intersection) permits runway turnoff speeds up to 60 mph.
The number and location of exit taxiways depend on the type and mix of aircraft
using the runway. At utility airports, three exit taxiways are generally suf?cient: one at
the center and one at each end of the runway. A modern air carrier runway may have
three angled exit taxiways for each landing direction plus several 90
?
exit taxiways.
For a given class of aircraft, the desired location of a high-speed exit taxiway can
be calculated based on the following design factors:
1. Distance from the threshold to touchdown
2. Touchdown speed
3. Initial exit speed (turnoff speed at the point of curvature) (PC)
4. Rate of deceleration
Other planning factors include location of the terminal/apron area, location of
other runways and their exits, optimization of traf?c ?ow in the operational area, and
avoidance of unnecessary taxi detours (1).
The distance from the threshold to touchdown averages about 1500 ft for turbojet
aircraft (categories C and D)
*
and approximately 1000 ft for other aircraft (category
B). Typical touchdown speeds are 164, 202, and 237 ft/sec, respectively, for category
B, C, and D aircraft.
Initial exit speeds are generally taken to be 40 mph (59 ft/sec) for small aircraft
and 60 mph (88 ft/sec) for large aircraft with a deceleration rate of 5 ft/sec
2
(1). The
ICAO recommends a deceleration rate of 1.25 m/sec
2
(4.1 ft/sec
2
) for computing the
location of exit taxiways (13).
Using its own classi?cation, the ICAO groups aircraft according to their threshold
speeds:
Group A Less than 169 km/hr (91 knots)
Group B Between 169 km/hr (91 knots) and 222 km/hr (120 knots)
Group C Between 223 km/hr (121 knots) and 259 km/hr (140 knots)
Group D Between 261 km/hr (141 knots) and 306 km/hr (165 knots)
*
The categories here refer to groupings of airplanes in U.S. Standard for Terminal Instrument Procedures
(TERPS). These categories, which are made on the basis of approach speed and maximum landing weight,
should not be confused with those mentioned in Section 6-4 for the ICAO categories designated by the
same letters.
TAXIWAY
RUNWAY
50' R
200'
3'
P.C.
120' R
100' R
40'
25' R
C
L
C
L
600'
800'
45°
250'
200'
3'
250' R.
MIN.
150' R. FOR 200' R/W
175' R. FOR 150' R/W
R
MIN.
W
T
S
R
MIN.
P.C.
W
C
W
C
TAXIWAY
C
L
RUNWAY C
L
RUNWAY
TRAFFIC FLOW
C
L
TAXIWAY
25'R (7.5M)
25'R (7.5M)
800'R (250M)
30°
C
L
(a)
(b)
(c)
Figure 8.17 Common types of exit taxiways: (a) angled exit taxiway for small airplanes;
(b) 90
?
exit taxiway; (c) angled exit taxiway for large airplanes (13).
The distance from touchdown to ideal exit location can be determined by the
following formula:
D =
(S
1
)
2
- (S
2
)
2
2a
(8.5)
where
S
1
= runway touchdown speed (ft/sec)
S
2
= runway initial exit speed (ft/sec)
a = deceleration (ft/sec
2
)
The distance from the threshold to the PC of the exit curve is determined by adding
to D a distance of 1000 or 1500 ft, as appropriate. Normally, it is necessary, however,
to correct this distance for local altitude and temperature conditions. It is suggested
that exit taxiway distances from the threshold be increased 3% per 1000 ft of altitude
over that required for standard sea level and 1.5% per 10
?
F above 59
?
F.