CEE 4674 Homework 5

Spring 2009

Assignment 5: Geometric Design Standards Date Due: March/6/2009 by COB Instructor: Trani

Problem #1 A new airport in Nevada (near Las Vegas) is expected to serve business jets and regional jets using a single 7,500 foot runway. The airport is expected to have an ILS Category 1 precision approach system available to both runway ends. After consultation with airlines and corporate flight departments, the largest and most critical aircraft to operate from the facility is the Embraer 195 regional airliner (see Figure 1). The aircraft has an approach speed of 125 knots at maximum allowable landing weight.

Figure 1. Dimensions and Layout of the Embraer 195 Regional Aircraft.

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CEE 4674 Homework 5

Spring 2009

a) Determine the dimensions of the complete runway taxiway layout shown in Figure 2 (for the new airport). Clearly indicate the FAA standards used.

Figure 2. Simplified Airport Layout for Problem 1. The critical aircraft is the Embrer 195. The wingspan of the aircraft makes the aircraft ADG III. See Table below.

Use ADG-III as critical aircraft and approach categories C and D.

Dimension

Length - feet (meters)

Remarks

B

100 (30)

Runway width (Table 3-3)

C

500 (150)

Runway safety area width (Table 3-3)

D

400 (122)

Runway to taxiway centerline distance (Table 2-2)

E

118 (36)

Taxiway safety area width (Table 4-1)

G

500 (150)

Runway to aircraft parking area (Table 2-2)

J

152 (46.5)

Taxiway to parallel taxiway/taxilane distance (Table 2-3)

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CEE 4674 Homework 5

Dimension

Spring 2009

Length - feet (meters)

Remarks

K

93 (28.5)

Taxiway to fixed/movable object (Table 2-3)

P

1000 (300)

RSA length beyond runway end (Table 3-3)

Q

800 (244)

ROFA width (Table 3-3)

R

1000 (300)

ROFA beyond runway end (Table 3-3)

W

50 (15)

Taxiway width (Note that landing gear wheelbase is less than 60 feet) (Table 4-1)

Z

81 (24.5)

Taxilane to fixed/movable object (Table 2-3)

b)Find the size of the runway and taxiway shoulders needed at this airport. The runway shoulders need to be 20 feet (6 meters) (Table 3-3). The taxiway width will be 20 feet (6 meters) (Table 4-1). c)Assuming the top of Figure 2 is the North side of the airport, find the closest distance from the runway that a developer could build a 4-story hotel (say 50 feet tall). Explain the controlling surfaces and dimensions considered in your analysis. Surfaces to be tested: 1) Transitional surface extending at a slope 7:1 outwards from the primary surface and 2) the runway Transitional surface drawing

Figure 3. Transitional Surface Schematic. From figure 3 it is clear that the hotel is restricted to a minimum of 850 feet from the runway centerline. This will be in compliance of the Part 77 transitional surface. Runway OFZ surface schematic.

Figure 4. Runway OFZ Surface Schematic. According to FAA design standards, “for CAT I runways, the inner transitional OFZ begins at the edges of the runway OFZ and inner-approach OFZ, then rises vertically for a height "H", and then slopes 6 (horizontal) to 1 (vertical) out to a height of 150 feet (45 m) above the established airport elevation.” The dimension of H is given by,

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CEE 4674 Homework 5

Spring 2009

Hfeet = 61 - 0.094(Sfeet) - 0.003(Efeet) where S is equal to the most demanding wingspan of the airplanes using the runway and E is equal to the runway threshold elevation above sea level. Using the airport elevation at Las vegas (LAS), for the Embraer 195 aircraft the dimension H is: H = 61 - 0.094 (94.25) - 0.003 (2181) or 45.6 feet.

Figure 5. Solution for OFZ Inner Transitional Surface. The solution depicted in Figure 5 illustrates the inner transitional surface. The dominant effect for the BRL is the Part 77 transitional surface. The Building is restricted to 850 feet from the runway centerline (see Figure 3). d)Research on the internet the differences between Categories 1, 2 and 3 of the instrument landing system (ILS). Find the visibility minima allowed for landings under each type of ILS system.

Category

Runway Visual Range (feet)

Decision Height (feet)

Category I

2000

200

Category II

< 2000 and >= 1000

100

Category IIIa

< 1000 and >= 700

0

Category IIIb

< 700 and >=150

0

Category IIIc

< 150 and >= 0

0

Problem #2 a)For problem described on page 37 of the revised geometric design handout (Notes 9), design a transition curve for point B (see Figure 6). Specify the elevations (every 10 meters) as a function of the station (in meters). Refer to the formulas on page 41 of the handout to create a symmetrical parabola. Do it in Excel or Matlab to simplify your work. The change in grade is 1.4% (from 1.1% to -0.3%) therefore the length of the transition curve us 1,400 feet (427 meters). The point of intersection is located at station 1806 metric. Since the parabola is symmetrical the starting point of the transition curve is located at station 5223.4 feet ((1806 - 427/2)*3.28) or metric station 1592.5. The elevation of Point B can be easily calculated to be 625.951 meters above mean sea level. The elevation of the starting point of the transition curve is 625.951 - (427/2) * (1.1/100) = 623.6025 meters. Using the Matlab code provided in class the following transition curve is obtained (Figure 7).

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CEE 4674 Homework 5

Spring 2009

Figure 6. Runway longitudinal Grades for Problem 2.

Figure 7. Transition Curve for Point B. b)Find the maximum permissible longitudinal grade for the first 200 feet of the runway safety area of the runway shown in Figure 6. According to the FAA AC 150/5300-13 the maximum grade for the 200 foot runway safety area is -3%.

Figure 8. FAA Maximum Permissible Runway Longitudinal Grades.

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CEE 4674 Homework 5

Spring 2009

c) If the runway shown in Figure 3 serves aircraft in approach speed categories A and B would it meet all the current longitudinal grade FAA standards. Explain.

Figure 9. Runway Longitudinal Grades for Approach Categories A and B. The maximum longitudinal grades are below 2% (OK). The maximum grade change is below 2% (OK). The distance between points of intersection is 2742 feet. This easily meets the required minima (486 feet). The runway would comply with all requirements of approach categories A and B.

Problem #3 The new airport in Florida with a 9000 foot runway needs runway exits. The airport authority wants at least three 90 degree exits for the runway to serve distinct aircraft groups shown in Table 1. These three exits are in addition to the 90 degree angle exits at the end points of the runway. Table 1. Aircraft Parameters for Problem 4. Refer to Matlab Code in Notes 9 Handout for Explanations. All other Parameters are Assumed to Take Values Defined in the Handout.

Aircraft Group

Parameters

Representative Aircraft (REDIM Name)

Small single-engine GA aircraft

Approach speed = 110 knots Touchdown location = 275 meters Average deceleration = -1.3 m/s-s Free roll time = 2.5 seconds

Cessna 208 (CE-208), Beech F33 (BEF33A)

Business jets

Approach speed = 125 knots Touchdown location = 350 meters Average deceleration = -1.4 m/s-s Free roll time = 2.0 seconds

Cessna 550 (CE-550), Learjet 31 (Learjet 31),

Medium-size transport aircraft

Approach speed = 140 knots Touchdown location = 420 meters Average deceleration = -1.4 m/s-s Free roll time = 2.0 seconds

Boeing 737-400 (B-737-400), Airbus A320 (A-320-200)

a) Find three runway exit locations (one for each aircraft group) using the three point method. Consider that the runway is used from both directions.

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CEE 4674 Homework 5

Aircraft Group

Spring 2009

Parameters

Results

Small single-engine GA aircraft

Approach speed = 110 knots Touchdown location = 275 meters Average deceleration = -1.3 m/ s-s Free roll time = 2.5 seconds

Flare distance = 275 meters Transition distance = 135.6 meters Braking distance = 980.6 meters Total Distance to Runway Exit = 1391.2 meters

Business jets

Approach speed = 125 knots Touchdown location = 350 meters Average deceleration = -1.4 m/s-s Free roll time = 2.0 seconds

Flare distance = 350 meters Transition distance = 123.0 meters Braking distance = 1188.5 meters Total Distance to Runway Exit = 1661.5 meters

Medium-size transport aircraft

Approach speed = 140 knots Touchdown location = 420 meters Average deceleration = -1.4 m/s-s Free roll time = 2.0 seconds

Flare distance = 420 meters Transition distance = 137.7 meters Braking distance = 1510.5 meters Total Distance to Runway Exit = 2068.2 meters

The solution to the problem assumes a typical exit speed of 8 knots. This is consistent with observed values for rightangle runway exits. Since the runway is 9000 feet long (2744 meters), we can sketch the following diagrams. Figure 11 shows the recommended solution to the problem using the runway from both directions. Note that a single runway exit is located at the midpoint (1372 meters) to service small aircraft. This location is 20 meters from the optimal location and seems a reasonable tradeoff to avoid two runway exits 40 meters apart. Figure 12 illustrates a solution with 3 runway exits.

Figure 10. One Direction Runway Exit Locations. Locations in Meters from Runway Threshold.

Figure 11. Bi-Directional Runway Exit Locations. Locations in Meters from Each Runway Threshold. Five Runway Exits Plus two Runway End Exits.

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CEE 4674 Homework 5

Spring 2009

Figure 12. Bi-Directional Runway Exit Locations. Locations in Meters from Each Runway Threshold. Three Runway Exits Plus two Runway End Exits. b) Specify the radius of the centerline curve to be used in the construction of the three runway exits. Since the airport is used by multiple aircraft groups use the critical aircraft as the basis for your selection. The radius of a 90-degree runway exit is 250 feet.

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