Download - Quiz 3 (Take Home - 2 Hours Maximum)

CEE 4674: Airport Planning and Design Spring 2012

Quiz 3 (Take Home - 2 Hours Maximum)SolutionInstructor: Trani

Instructions

Write your solutions in a single Word file and create a PDF file. Cut and Paste all your answers using screen captures. Show all your work. Label your file with your last name and CEE4674. Email your PDF solutions to [email protected] and to [email protected] In the email header use the words CEE 4674 Quiz. If you are in Blacksburg you can provide your answers in the hard copy of the Exam or else electronically per instructions above.

Honor Code PledgeThe information provided in this exam is my own work. I have not received information from another person while doing this exam.

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CEE 4674 Trani Page 1 of 17

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Problem #1 (50 points)An airport shown in Figure 1 has a two 10,000 feet precision runways. The two runways are used in segregated mode (i.e., one for arrivals and one for departures) as shown in Figure 1. The airport has a standard airport surveillance radar (ASR) which tracks aircraft up o 60 miles form the airport site. The radar has a scan rate of 4.0 seconds. Table 1 shows the technical parameters for the airport. Use the approach speeds at maximum landing weight for the representative aircraft to compute the runway saturation capacity. Tables 2 and 3 show the typical ATC separations at the airport under IMC conditions. Two aircraft groups operate at the airport. The airport has the following technical parameters: a) in-trail delivery error of 20 seconds, b) departure-arrival separation for both VMC and IMC conditions is 2 nautical miles, c) probability of violation is 5%. Arriving aircraft are “vectored” by ATC to the final approach fix located 9 miles from the runway threshold. Arrivals follow in-trail after crossing the final approach fix.

Figure 1. Airport Configuration for Problem 1.


Figure 2. Boeing 747-400 Engine Exhaust Velocity Profiles at Maximum Thrust. Source: Boeing Aircraft Co. Consult the Boeing Documents for Airport Design for Engine Exhaust Profiles of Other Aircraft.

Table 1. Airport Arrival and Departure Operational Procedures for Problem 1.

Parameter Large Heavy

Runway Occupancy Time (seconds)

54 60

Fleet Mix (%) 70 30

Representative Aircraft Boeing 737-400 Boeing 747-400


Table 2. Minimum arrival-arrival separations under IMC conditions. Values in are nautical miles. Values Shown Do Not Include Buffers.

Table 3. Minimum departure-departure separations under IMC conditions. Values in are seconds.

a) Using the information provided, estimate the Pareto Diagram showing the saturation arrival and departure capacities for this airport in IMC conditions.

SolutionUsing the FAA advisory circular we find the typical values of approach speeds for Boeing 737-400 and Boeing 747-400 to be 139 and 154 knots, respectively.The calculation of arrivals only yields 30 operations per hour. 46.5 departures per hour are possible in this scenario on the departures-only runway. The mix operations solution is not applicable to this problem because both runways are operated in segregated mode (independent of each other). The Pareto diagram is shown in Figure 3.


Figure 3. Pareto Diagram for Two Runway System. Runways are Fully Independent Operated in Segregated Mode and under IMC Conditions.

b) The airport authority hears numerous complains from pilots landing on runway 27 at this airport. When a large or heavy aircraft start their takeoff roll on runway 36, the engine exhaust velocity profiles behind the aircraft pose a hazard to aircraft landing on runway 27. The velocity profiles for a Boeing 747-400 are shown in Figure 2. Note that the 35 mph contours extend to 1,560 feet. In other words, the aircraft taking off on runway 36 generate large localized “cross wakes” that affect operations on the landing runway. Generally speaking a 35 mph cross wind is considered unacceptable for routine landing operations. The engine exhaust wake dissipates to harmless levels in 25 seconds after the aircraft starts its takeoff roll.

Considering these facts, revise the saturation capacity for departures on runway 36 obtained in Part (a). Explain the logic on how did you revise the Pareto diagram.

Solution

The aircraft have known approach speeds (139and 154 knots). This translates 234 ft/second for the boeing 737-400. To calculate the saturation capacity on runway 36-18 we need to start a sequence of operations as shown in Figure 4. In the figure we start with the lead aircraft crossing the runway (aircraft 1). The following aircraft (aircraft 2) is behind at a headway (Tij + Bij) seconds away. The third aircraft (3) is line up and wait (holding on runway 36) ready to go. Note that in this situation, aircraft 3 idles on the departing runway and thus no wake effect is felt by aircraft 1. Figure 5 illustrates the situation 14.5 seconds later when aircraft 3 (takeoff) starts its takeoff roll 10 seconds after aircraft 1 crosses the plane of runway 18-36. Figure 6 illustrates the situation where aircraft (3) is 25 seconds into the takeoff roll. At that point the wake created by the engine exhaust has dissipated and poses no threat to the arriving aircraft (2). Assume a safety distance x is necessary for the controller to process the next arrival. This solution is similar to that of an intersecting runway scenario except that the operational interaction between the two aircraft is shorter.


Figure 4. Initial Conditions to Estimate Runway Saturation Capacity. Time = 0 seconds.

Figure 5. Conditions to Estimate Runway Departure Saturation Capacity. Time = 14.5 seconds.


Figure 6. Conditions to Estimate Runway Departure Saturation Capacity. Time = 39.5 seconds. The analysis focuses on whether arrival gaps allow the distance d to be greater than the minimum allowed distance x.

Table 4. Times for Following Aircraft (2) to Reach Threshold for Conditions Shown in Figure 6.

Following Aircraft

Lead Aircraft (below) Large Heavy

Large 71.2 63.63

Heavy 133.1 63.63

Table 5. Following Aircraft (2) Distance in nautical miles to Reach Threshold for Conditions Shown in Figure 6.

Following Aircraft


Large 2.75 2.72

Heavy 5.14 2.72

If the critical distance x is set to be 1 nm, each gap shown in Table 5 provides enough capacity for at least one departure. The obvious question is can any gap provide enough capacity for more than one departure?


Departures with d >= 1nm

Consider gap left when Large follows Large. The trailing aircraft is 2.75 nm from the threshold when the wake interaction disappears. This leaves 1.75 nm to release another departure. At that point the arriving aircraft (2) would be The departure-departure separation is known on average to be 78 seconds. A large aircraft approaching at 139 knots would be 45 seconds from the threshold when at a point 1.75 nm away. This provides no opportunity for a second departure in that gap. Similarly, when Large-Heavy combinations are examined, the gaps are only sufficient to support one departure in every gap if, once again, the controller leaves a 1 nm buffer margin between the wake of the aircraft and the time when the aircraft arrives to the threshold.

The Heavy-Large gap is more promising. Here we have 4.14 nm left as true gap for the second arrival. A large aircraft requires 107 seconds to cover the 4.14 nm gap and thus a second departure is possible. Three departures would require 120 seconds of gap so it will not be possible to release a third departure in that gap. A Table with the number of departures per arrival gap is constructed and shown in Table 6. Table 8 shows the calculated expected departures for each arrival gap.

Table 6. Departures per Arrival Gap with d=0.5 nm.

Following Aircraft


Large 1.00 1.00

Heavy 2.00 1.00

Table 7. Probability Matrix for Arrival Runway Operations.

Following Aircraft


Large 0.49 0.21

Heavy 0.21 0.09

Table 8. Expected Departures for Runway Operations with d=1 nm. Total Departures per Hour = 35.

Following Aircraft


Large (29 gaps) * (0.49) * 1 = 14.2 (29 gaps) * (0.21) * 1 = 6.1

Heavy (29 gaps) * (0.21) * 2 = 12.2 (29 gaps) * (0.09) * 1 = 2.6


Departures with d >= 0.5 nm

Consider gap left when Large follows Large. The trailing aircraft is 2.75 nm from the threshold when the wake interaction disappears. This leaves 2.25 nm to release another departure. At that point the arriving aircraft (2) would be The departure-departure separation is known on average to be 78 seconds. A large aircraft approaching at 139 knots would be 58 seconds from the threshold when at a point 2.25 nm away. This provides no opportunity for a second departure in that gap. Similarly, when Large-Heavy combinations are examined, the gaps are only sufficient to support one departure in every gap if, once again, the controller leaves a 0.5 nm buffer margin between the wake of the aircraft and the time when the aircraft arrives to the threshold.

The Heavy-Large gap is again more promising. Here we have 4.64 nm left as true gap for the second arrival. A large aircraft requires 120 seconds to cover the 4.64 nm gap and thus a second departure is possible. Three departures would require 158 seconds of gap so it will not be possible to release a third departure in that gap. Tables 9 and 10 illustrate this solution.


Following Aircraft


Large 1.00 1.00

Heavy 2.00 1.00

Table 10. Expected Departures for Runway Operations with d=0.5 nm. Total Departures per Hour = 35.

Following Aircraft


Large (29 gaps) * (0.49) * 1 = 14.2 (29 gaps) * (0.21) * 1 = 6.1

Heavy (29 gaps) * (0.21) * 2 = 12.2 (29 gaps) * (0.09) * 1 = 2.6


Departures with d >= 0.0 nm (arrival when engine exhaust wake dissipates)

Consider gap left when Large follows Large. The trailing aircraft is 2.75 nm from the threshold when the wake interaction disappears. This leaves 2.75 nm to release another departure. At that point the arriving aircraft (2) would be The departure-departure separation is known on average to be 78 seconds. A large aircraft approaching at 139 knots would be 72 seconds from the threshold when at a point 2.75 nm away. This provides no opportunity for a second departure in that gap. Similarly, when Large-Heavy combinations are examined, the gaps are only sufficient to support one departure in every gap if, once again, the controller leaves no buffer margin between the wake of the aircraft and the time when the aircraft arrives to the threshold.

The Heavy-Large gap is again more promising. Here we have 5.14 nm left as true gap for the second arrival. A large aircraft requires 133 seconds to cover the 5.14 nm gap and thus a second departure is possible. Three departures would require 158 seconds of gap so it will not be possible to release a third departure in that gap. Tables 9 and 10 show the solution with d >= 0.5 nm.


Following Aircraft


Large 1.00 1.00

Heavy 2.00 1.00

Table 11. Expected Departures for Runway Operations with d=0.0 nm. Total Departures per Hour = 35.

Following Aircraft


Large (29 gaps) * (0.49) * 1 = 14.2 (29 gaps) * (0.21) * 1 = 6.1

Heavy (29 gaps) * (0.21) * 2 = 12.2 (29 gaps) * (0.09) * 1 = 2.6

Conclusion

Based on the assumptions made, three solutions were investigated and all three provided the same answer. When engine exhaust wake is considered, the number of operations on runway 36 is reduced from 46 per hour to 35 per hour. This is a substantial reduction in the departure saturation for this airport. The new Pareto diagram is shown in Figure 7.


Figure 7. Pareto Diagram with Engine Exhaust Interaction.


Problem # 2 (50 points)The airport shown in Figure 8 has a total of 12 gates per terminal. Each terminal is served by a security area shown in green. A detailed configuration of the security area is shown in Figure 9. After studying the airline schedules at the airport and after doing a random survey of passenger flows at the security area, a demand pattern has been observed to repeat every 3 hours at the airport starting at 5:00 AM and ending around 20:00 hrs. This demand patterns coincides with 3-hr banks of flights at the airport. The passenger arrival demand to the security area for Terminal 1 is shown in Table 1.

Figure 8. Airport Terminal Configuration.

Figure 9. Detail of Security Area Showing 8 Body and Carry-on Baggage Scanners.


Table 12. Arrival Demand Function at Security Area.

Time (hrs) Passengers per Hour Arriving to Security Area

5.00 360

5.25 640

5.50 850

5.75 900

6.00 810

6.25 720

6.50 640

6.75 500

7.00 460

7.25 360

7.50 360

8.00 360

a) Estimate the dimensions D1 and D2 of the airport terminal to serve Airbus A330-300 aircraft at each gate. Provide dual taxilanes between Terminals 1 and 2.

a1) A330-300 require 25 feet between adjacent wingtips (see page 17 of the course notes). The total length of the pier terminal (D1) is 1,350 feet (using 200 feet as the critical wingspan).

a2) For dual taxilane operations we require 2.3 x critical wingspan + 30 feet. The Airbus A330-300 has a wingspan of 197 ft 10 inches (use 200 feet in the analysis). The length of the aircraft is 209 feet. Assume dual service roads on each side for vehicles and allowing 30 feet from nose to terminal interface, the total dimension D2 is 906 feet.


Figure 10. Airport Terminal and Dimensions.!

b) Find the maximum queue length at the security area of Terminal 1 if the passenger service time is deterministic at 45 seconds per passenger per scanner. The demand function is also deterministic and shown in Table 1.

The service rate for each server in the security area is,

µ = 3600s / hr45s / pax

= 80passengers / hr

Since there are 8 servers in each security area, the combined service rate of all serves is 640 passengers/hr. Use the deterministic queueing model since the demand function is fully known over time and no distribution is provided. Figure 10a illustrates the input parameters to the deterministic queueing model.


Figure 10a. Parameters of Deterministic Queueing Model.

Integrating the service and demand rates we estimate 238.5 passengers hours of total delay.

Total delay (passengers-hour) = 238.5 Max queue length (passengers) = 180 passengers

Figure 11. Service and Demand Rates and Queue Length at Security Area 1.


Figure 12. Queue Length and Total Delay Functions.!

c) Find the dimension D3 based on the result found in part (b). Assume a person waiting in line requires a personal space of 1 square meter. Assume 1 meter as the typical width of each lane where passengers wait in line.

The dimension of distance D3 is predicated on the maximum queue length expected. For 30 meter width of the holding area in the security area we need 7 parallel lanes to satisfy the design. This implies 7 meters in depth.


Figure 13. Security Area Dimensions.
