Appendix D
Appendix D D.1 Introduction The set of alternatives for each of the airfield facilities was compared with respect to each other and the existing condition. 1 The screening and evaluation process considered the following evaluation criteria: Constructability/Phasing: minimizing construction impacts on Airport and airline operations. Operational Efficiency: increasing the overall efficiency of aircraft movements by avoiding operating restrictions and reducing airfield congestion. This appendix presents the alternatives development and evaluation process for SFO airfield projects not related to capacity increases projected during the ADP planning horizon. The majority of ongoing airfield projects stem from a need for compliance with FAA design standards and increased aircraft maneuvering flexibility, rather than enhancing capacity. The proposed taxiway alternatives were developed to increase compliance with FAA design standards to: Meet FAA taxiway separation standards Reduce the complexity of taxiway/runway intersections Reduce congestion Provide for additional airfield signage Reduce the number of acute-angle runway crossings Reduce aircraft departure dependencies Reduce the potential for pilot confusion As SFO is a legacy, land-constrained Airport, it is infeasible to rebuild the entire airfield to reflect modern design standards. The airfield alternatives assessment balances compliance with design standards and consideration of land constraints. D.2 Alternatives Development and Evaluation Criteria The taxiway alternatives analysis focuses on improving the SFO taxiway system by addressing areas of nonconformance. Portions of the existing taxiway system have geometries that do not meet FAA design standards and insufficient separation distances from runways and adjacent taxiways. Multiple alternatives were evaluated based on a set of qualitative evaluation criteria detailed in this section. The alternatives maintain the operational efficiency of the airfield and comply with the current FAA standards and guidelines while considering the effects on existing facilities, the environment, constructability, and cost. D.2.1 Evaluation Criteria The primary focus of the evaluation process was to assess the ability of each alternative to satisfy FAA standards and requirements through physical improvements or operational procedures. The airfield alternatives must meet Airport management s goal of SFO being the top-rated airport among passengers while controlling costs, increasing operational efficiency, minimizing disruption to airline and Airport operations, and ensuring the optimization of vital land resources for aviation use. Environmental Considerations: minimizing the negative environmental impacts related to aircraft noise, wetlands/shoreline, wildlife, and air quality. Impacts to Existing Facilities: maximizing the use of existing airfield infrastructure while minimizing disruption of existing facilities. FAA Standards and Guidelines: enhancing safety through the implementation of current FAA guidelines, limiting the number of Modifications of Standards (MoS), and mitigating operational procedures. Cost (Recommended Alternatives only): minimizing the order-of-magnitude estimated construction costs and potential loss of Airport revenue. The screening of initial alternatives used a three-tiered rating system to evaluate how well each alternative would meet the evaluation criteria. A summary for each rating explains the benefits and impacts of each alternative. The symbols used in the evaluation matrix are as follows: Major Benefit / Minor Impact Moderate Benefit / Moderate Impact Minor Benefit or Deficient / Major Impact This evaluation resulted in a preliminary set of recommended alternatives. Next, cost estimates for each recommended alternative assessed the financial feasibility on a cost-benefit basis. Airport management used this analysis to narrow the alternatives to be carried forward for further analysis. Selected and eliminated alternatives are marked as follows: Selected Alternatives Eliminated Alternatives The highest-rated preliminary alternatives were combined into an intermediate airfield development plan. This plan was presented to FAA SFO ATCT and FAA San Francisco ADO staff for review and comment. With this input, the intermediate airfield development plan was refined into the recommended alternative development plan presented in Section D.3.3. 1 The existing condition is a baseline, commonly known as the no-build alternative. Draft Final: September 2016 Appendix D Page 1 Draft Final: September 2016 Appendix D Page 2
D.3 Airfield Alternatives and Evaluation The current SFO Airport Layout Plan (ALP) 2 depicts new taxiway developments and modifications to existing taxiways to improve taxiway flows, and provides greater flexibility for aircraft movements while mitigating areas of nonconformance. These proposals were reevaluated in Sections D.3.1 and D.3.2 to determine their conformance with design standards and the alternatives developed for this analysis. Sections D.3.3 through D.3.9 detail the evaluation for alternatives that were developed during this alternatives selection process. Exhibit D.3-1 Taxiways S Improvement on Airport Layout Plan D.3.1 Taxiway S Fillet Exhibit D.3-1 depicts the proposed Taxiway S fillet. This fillet would allow aircraft to depart Runway 10L from Taxiway S3 and Runway 10R from Taxiway S without incurring a wake turbulence penalty. Without this fillet, aircraft departing Runway 10L must enter the runway from Taxiway S4 when aircraft depart Runway 10R using Taxiway S. 2 The SFO ALP, dated January 2014 and conditionally approved by the FAA in June 2014, depicts the existing facilities and planned development for the Airport. Taxiway S Fillet Evaluation Table D.3-1 shows the evaluation matrix for the Taxiway S Fillet. The evaluation matrix shows that the proposed project provides benefits with no adverse impact to existing facilities or operations. Therefore, it was carried forward into the recommended airfield development plan. Draft Final: September 2016 Appendix D Page 3 Draft Final: September 2016 Appendix D Page 4
Table D.3-1 Evaluation of Taxiway S Fillet Alternative Existing Conditions Alternative 1 Evaluation Criteria No Build Taxiway S fillet Constructability/Phasing N/A The Taxiway W connector would provide additional flexibility for aircraft to cross Runway 10R-28L or Runway 10L-28R during visual metrological conditions (VMC). The location of the existing glideslope antenna between the runways would not allow aircraft to occupy this proposed connector taxiway during arrivals on Runways 28L and 28R in IMC. Exhibit D.3-2 Taxiways N and F2 Improvements on Airport Layout Plan Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $1.0 million Recommended Airfield Development Plan D.3.2 Access Improvements to Runway 28L Exhibit D.3-2Exhibit D.3-2 depicts the proposed realignment of Taxiway N. With the existing taxiway configuration, aircraft that plan to depart Runway 28L yet cancel the takeoff must taxi approximately 4,000 feet to Taxiway L to rejoin the departure queue. This realignment would enable those aircraft to exit the runway at Taxiway N and rejoin the departure queue on Taxiway F. The Taxiway N alignment also allows for a quicker entrance to and exit from Runway 28L. Exhibit D.3-2 also depicts the proposed taxiway access improvements to Runway 28L. During instrument meteorological conditions (IMC), aircraft departing Runway 28L are required to remain clear of the instrument landing system (ILS) hold position and precision obstacle free zone (POFZ) when aircraft are arriving on Runway 28L. Future Taxiway F2 is located outside of the POFZ, which would allow an aircraft to hold for departure closer to the runway. Furthermore, in all weather conditions, future Taxiway F2 would reduce the aircraft taxi time to the runway for departure and allow aircraft to bypass other aircraft parked adjacent to the runway on Taxiway F. An additional alternative for the Taxiway F2 connector was developed as part of this analysis process. Exhibit D.3-3 depicts an extension of Taxiway W that would act as a connector between Taxiway W and Taxiway F2. Draft Final: September 2016 Appendix D Page 5 Draft Final: September 2016 Appendix D Page 6
Exhibit D.3-3 Taxiways N and F2 Improvements on Airport Layout Plan with Taxiway W Connector Table D.3-2 Evaluation of Airport Layout Plan (ALP) Improvements Evaluation Criteria Existing Alternative Alternative Alternative Conditions No Build 1 Taxiway N 2A Taxiway F2 2B Taxiway F2 with Taxiway W Connector Constructability/Phasing N/A Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $2.9 million $5.2 million Recommended Airfield Development Plan Source: Ricondo & Associates, 2015 Access Improvements to Runway 28L Evaluation The access improvements to Runway 28L depicted on the FAA-approved Future ALP include the Taxiway N realignment and a new Taxiway F2. An additional alternative, the Taxiway W connector, was developed through this analysis. Because of its impacts on the other two alternatives, it was evaluated together with them. Table D.3-2 shows the evaluation matrix for these improvements. The evaluation of the benefits and impacts of Taxiway N and Taxiway F2 justified their inclusion in the recommended airfield development plan. The Taxiway W Connector was eliminated due to the impact on the existing glideslope during construction and the inability to use the taxiway during ILS approaches to Runways 28L and 28R. The Taxiway N realignment and Taxiway F2 construction were carried forward into the recommended airfield development plan. Draft Final: September 2016 Appendix D Page 7 Draft Final: September 2016 Appendix D Page 8
D.3.3 Taxiway Z Runway Safety Area Penetration Aircraft taxiing on Taxiway Z north of Taxiway Y penetrate the Runway 10R-28L runway safety area (RSA). The 500-foot-wide RSA extends 1,000 feet beyond the runway threshold and must remain clear of aircraft during runway operations. Exhibit D.3-4 depicts the two alternatives that were developed to prevent aircraft from entering the RSA. Alternative 1 would incorporate a hold position marking on Taxiway Z. During arrivals and departures on Runway 10R-28L, aircraft would hold short of this marking until the runway is clear. This marking would be positioned as far north as possible while ensuring that the wing of an ADG VI aircraft would remain outside the RSA. Alternative 2 would realign the Taxiway Z centerline 150 feet outside of the RSA (400 feet from the extended runway centerline), allowing ADG VI aircraft to pass while remaining clear of the RSA. This alternative would require relocation of an adjacent VSR, blast fence, an electrical transformer, and pump stations for the industrial waste and sanitary sewer systems. This alternative would result in the loss of less than 0.8 acre of surface automobile parking. Exhibit D.3-4 Taxiway Z RSA Alternative Taxiway Z Runway Safety Area Penetration Evaluation Table D.3-3 shows the evaluation matrix for the Taxiway Z RSA penetration alternatives. The existing condition does not meet current FAA RSA standards. Both alternatives would bring the Taxiway Z RSA into compliance with FAA RSA standards; however, Alternative 2 was eliminated from further consideration due to the significant disruption to surrounding facilities and high cost. Alternative 1 has been carried forward as part of the recommended airfield development plan. Table D.3-3 Evaluation of Taxiway Z Runway Safety Area Alternatives Evaluation Criteria Existing Conditions Alternative 1 Alternative 2 No Build Existing Taxiway Z Hold Position Realigned Taxiway Z for ADG VI Aircraft around Runway 10L- 28R RSA Constructability/Phasing N/A Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost Minimal Recommended Airfield Development Plan Source: Ricondo & Associates, 2015 D.3.4 Taxiway C Separation Taxiway C runs parallel to Runway 10L-28R at 500 feet from the runway centerline. A runway-to-taxiway separation of 550 feet is required for Runway 10L-28R because it accommodates ADG VI aircraft with a CAT II/III ILS and visibility minimums of less than ½-statute mile. During CAT II/III ILS arrivals on Runway 28R, the CAT II/III ILS missed approach surface restricts the use of existing Taxiway C to aircraft with tail heights of approximately 72 feet or less. This limitation restricts A380-800 aircraft from taxiing on Taxiway C between Taxiway D and the Runway 28R threshold. Draft Final: September 2016 Appendix D Page 9 Draft Final: September 2016 Appendix D Page 10
Exhibit D.3-5 and Exhibit D.3-6 depict Alternative 1, which would shift the full length of Taxiway C by 50 feet. The ADG V and ADG VI OFAs for the northwest portion of Taxiway C would contain a detention basin and a VSR. The detention basin could remain because it is located outside of the taxiway safety area (TSA); 3 however, FAA standards 4 prohibit the VSR from being located inside the OFA and it would need to be shifted. The northwest portion of a shifted Taxiway C would render unusable the apron space immediately in front of the FBO hangars (Buildings 1050 and 1051) and reduce the overall apron area available by 185,000 feet. Exhibit D.3-6 depicts the southeast portion of a shifted Taxiway C. The seawall would remain outside of the ADG VI OFA, but the VSR would be within the ADG VI OFA. The distance between the seawall and the OFA is not sufficient to relocate the VSR outside of the ADG VI OFA. FAA design standards 5 prohibit roadways within the OFA, but vehicles may operate within the OFA provided vehicles yield the right-of-way to oncoming aircraft by maintaining a safe distance ahead or behind the aircraft or by exiting the OFA to let aircraft pass. This condition exists elsewhere on the existing airfield, including on Taxiway L. Vehicle pullout areas could be provided along the VSR, as depicted in Exhibit D.3-6. Exhibit D.3-5 Taxiway C Alternative 1 (Northwest) 3 TSA it the abbreviation for the taxiway safety area and the Transportation Security Administration; it is used to abbreviate both terms in the ADP. Within this appendix, however, TSA always references the taxiway safety area. 4 FAA Advisory Circular 150/5300-13A CHG 1, Airport Design, Chapter 4. Taxiway and Taxilane Design, 404.b.1. 5 FAA Advisory Circular 150/5300-13A CHG 1, Airport Design, Chapter 4. Taxiway and Taxilane Design, 415. Draft Final: September 2016 Appendix D Page 11 Draft Final: September 2016 Appendix D Page 12
Exhibit D.3-6 Taxiway C Alternative 1 (Southeast) Exhibit D.3-7 Runway 10R-28L Runway Object Free Zone for A380-800 during CAT II/III ILS Arrivals Exhibit D.3-8Exhibit D.3-8 depicts the CAT II/III ILS missed approach surface for Runway 28R. The missed approach surface consists of a trough-shaped section that slopes up and away from the runway centerline at a slope of 12:1 and a second surface starting 9,000 feet from the far end of the runway that slopes up and away in a perpendicular manner to the centerline at a slope of 40:1. The tail of an A380-800 (79.1 feet) on Taxiway C at the existing 500-foot separation penetrates this surface but only east of a point approximately 450 feet west of Taxiway E. A taxiway-to-runway separation of 550 feet east of this point would allow A380-800 aircraft to taxi without penetrating the missed approach surface. Runway-to-taxiway centerline separation standards are designed to keep taxiing aircraft from penetrating two three-dimensional imaginary surfaces: the runway object free zone (ROFZ) and CAT II/II missed approach surface. Exhibit D.3-7 depicts the runway object free zone (ROFZ) for an A380-800 on approach to Runway 10L-28R during CAT II/III ILS conditions. The ROFZ precludes aircraft and other objects from encroaching upon this surface when aircraft are operating on a runway, except for frangible navigational aids. The shape of the ROFZ surface is dependent on the approach minimums and the aircraft on approach. Ground elevation contours along Taxiway C indicate that the taxiway is lower than the runway and that the tail of an A380-800 (tail height of 79.1 feet) does not penetrate the CAT II/III ROFZ surface (79.1 feet above the runway centerline) with Taxiway C at the existing 500-foot separation. Therefore, the existing 500-foot Taxiway C separation from Runway 10L-28R is sufficient to accommodate ADG VI aircraft movements without penetrating the CAT II/III ROFZ. Draft Final: September 2016 Appendix D Page 13 Draft Final: September 2016 Appendix D Page 14
Exhibit D.3-8 Runway 10R-28L CAT II/III ILS Missed Approach Surface Exhibit D.3-9 Runway 10L-28R Combined CAT II/III ILS Missed Approach Surface and ROFZ (A380-800 and CAT II/III ILS) Exhibit D.3-9 depicts the combined ROFZ and CAT II/III ILS missed approach surface for Runway 10L-28R. Alternative 2, depicted in Exhibit D.3-10, would shift only the portion of Taxiway C required to clear both surfaces. This hybrid alternative increases the taxiway-to-runway separation to 550 feet for approximately 6,850 feet of the taxiway along Runway 28R. An MoS would be required to operate ADG VI aircraft on this runway because the northwest segment would not meet the FAA standard separation. This alternative would avoid impacts to the existing East Field apron or the existing VIP parking area while providing an equivalent level of safety compared to FAA standards. Exhibit D.3-10 Taxiway C Alternative 2 Draft Final: September 2016 Appendix D Page 15 Draft Final: September 2016 Appendix D Page 16
The effectiveness of this alternative must consider ADG VI activity on Taxiway C. The 550-foot runway-to-taxiway separation is required only during CAT II/III ILS approach operations, which occur less than 1 percent of the time, according to SFO ATCT staff. Departing ADG VI aircraft from B/A A typically access Runway 28R via Taxiways M, G, L, F, and N, as depicted in Exhibit D.3-11. These aircraft only require the portion of Taxiway C between Taxiway N and Runway 28R separated 550 feet from the runway. Departing ADG VI aircraft from B/A G typically access Runway 28R via Taxiway Z and the full length of Taxiway C, including the portion of that taxiway separated by 500 feet in Alternative 2. The alternate taxi route for ADG VI aircraft from B/A G is via Taxiway B through the terminal area and onto Taxiways F, N, and C. The SFO ATCT will generally avoid this route due to heavy traffic on those taxiways and the restrictions placed on Taxiway A when an ADG VI aircraft is taxiing on Taxiway C. The High Constrained design day flight schedule includes nine departures by A380-800 aircraft. Based on assumed boarding area assignments, seven of the A380-800 flights would depart from B/A A and two would depart from B/A G. Therefore, 0.29 percent of departures per day would use the northwest segment, which is nonstandard during weather conditions that occur less than 1 percent of the time. Exhibit D.3-11 Taxiway C Alterative 2 ADG VI Utilization Taxiway C Separation Evaluation Table D.3-4 shows the evaluation matrix for the Taxiway C separation alternatives. While Alternative 1 would meet FAA standards, it would significantly reduce the depth of the East Field apron. Alternative 2 would require an MoS for the portions of taxiway that remain at a 500-foot separation from Runway 10L-28R, but the impacts to existing facilities are minimal. Therefore, Alternative 2 was carried forward as part of the recommended airfield development plan. Table D.3-4 Evaluation of Taxiway C Separation Alternatives Evaluation Criteria Existing Conditions Alternative 1 Alternative 2 No Build Taxiway C realigned for full length Taxiway C realigned east of Plot 40A Constructability/Phasing N/A Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $25.8 million Recommended Airfield Development Plan Source: Ricondo & Associates, 2015 Draft Final: September 2016 Appendix D Page 17 Draft Final: September 2016 Appendix D Page 18
D.3.5 Runways 10L and 10R Access Taxiways Exhibit D.3-12 Runways 10L and 10R Thresholds Taxiways Alternative 1 Two alternatives were developed to improve access to Runways 10L and 10R. These modifications include straightening taxiway-runway intersection angles, increasing pilot situational awareness by removing taxiways used to enter the runway at an angle, and creating less complex taxiway and runway intersections. Both alternatives include the realignment of Taxiways C1 and S to enter the runways perpendicularly, removal of Taxiway S1, and consolidation of Taxiways U and R into a new Taxiway R crossing Runways 10L-28R and 10R-28L. The separation distance of 480 feet between entrance Taxiways S and S3 would enable departures to occur simultaneously on Runways 10L and 10R without incurring a wake turbulence penalty (see Section 0). These alternatives include the realignment of Taxiway Z as depicted in the current FAA-approved SFO ALP and completed in fall 2015. Exhibit D.3-12 depicts Alternative 1, in which Taxiway R would be separated by 500 feet from the realigned Taxiway S entrance taxiway. These modifications would allow departures to occur on Runway 10L using realigned Taxiway R and on Runway 10R from either Taxiway S, Z1, or R without incurring a wake turbulence penalty. SFO air traffic controllers would have greater flexibility in guiding aircraft to Runways 10L and 10R for departure. Exhibit D.3-13 depicts Alternative 2, in which Taxiway R would be aligned with an extended Taxiway B. This realignment would provide access for aircraft crossing the airfield from the terminal area to the maintenance area without using Taxiway Z. It would simplify the taxiway layout at the intersection of Taxiways Z, B, and A by creating a three-node taxiway intersection. A drawback of this alternative is that aircraft would not be able to taxi as quickly through this are a because of the 90-degree turns. This alternative would allow aircraft to taxi directly from Taxiway B onto a runway, which may increase the risk of runway incursions. Draft Final: September 2016 Appendix D Page 19 Draft Final: September 2016 Appendix D Page 20
Exhibit D.3-13 Runways 10L and 10R Thresholds Taxiways Alternative 2 Table D.3-5 Evaluation of Runways 10L and 10R Threshold Alternatives Evaluation Criteria Existing Conditions Alternative 1 Alternative 2 No Build Taxiway R with Existing Taxiway B Taxiway R with Realigned Taxiway B Constructability/Phasing N/A Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $5.3 million Recommended Airfield Development Plan Source: Ricondo & Associates, 2015 Runways 10L and 10R Access Taxiways Evaluation Table D.3-5 shows the evaluation matrix for the Runways 10L and 10R access taxiway alternatives. Alternative 2 was eliminated because (1) it provides direct access from Taxiway B onto a runway and (2) of the operational inefficiencies associated with the simplified taxiway layout at the intersection of Taxiway B and relocated Taxiway R. Alternative 1 was carried forward as part of the recommended airfield development plan due to its relatively low cost and ability to address the non-standard taxiway geometry issue. Draft Final: September 2016 Appendix D Page 21 Draft Final: September 2016 Appendix D Page 22
D.3.6 Taxiways F and F1 Separation Exhibit D.3-14 depicts four alternatives to alleviate congestion and taxiway complexity and to meet the FAA runway-to-taxiway separation standards by realigning Taxiways F and F1 between Taxiways B and P. ADG VI aircraft departing Runway 28R access the runway end by either taxiing around the thresholds of Runways 10R and 10L on Taxiway Z and onto Taxiway C or by crossing Runways 1L-19R and 1R-19L on Taxiway F, F1, G, or M. The missed approach surface for the Runway 28L ILS CAT II approach requires a separation distance of approximately 585 feet between Taxiway F and Runway 10R-28L. In each alternative, Taxiway F shifts 550 feet from the runway, allowing A380-800 aircraft to taxi unrestricted on Taxiway F during CAT II ILS operations and when A380-800 aircraft arrivals use Runway 28L. This arrangement requires a portion of the VSR to be relocated outside of the taxiway safety area (TSA). In Alternative 1, Taxiway F would shift to a separation of 550 feet from Runway 10R-28L and the eastern portion of Taxiway F1 would be eliminated. Runway 19L arrivals would be able to exit onto the realigned Taxiway F or the remaining segments of Taxiway F1. In this alternative, Taxiway F1 would be used as a runway exit taxiway only and would not be used to access the southeast airfield. In Alternative 2, Taxiway F would be relocated south of Taxiway F1, which would remain in its current configuration. The Taxiway F realignment would provide for a minimum taxiway-to-taxiway separation of 324 feet to accommodate dual ADG VI aircraft movements at the intersection of Taxiway B. The relocation of Taxiway F would reduce the complexity of FAA Hot Spot 1 and would allow simultaneous aircraft crossings of Runways 1L-19R and 1R-19L. The taxiways would be configured so that an aircraft using relocated Taxiway F would be able to cross the runways, turn onto Taxiway L, and hold for any aircraft on Taxiway F1, thus clearing Runway 1R for departures. In Alternative 3, Taxiway F would shift to a separation of 550 feet from Runway 10R-28L and Taxiway F1 would be realigned parallel at a separation of 324 feet from Taxiway F. These improvements would allow ADG VI aircraft to cross Runways 1L-19R and 1R-19L independently. However, there is not sufficient separation for an aircraft crossing on Taxiway F1 to clear the Runway 1R-19L RSA while Taxiway F is occupied, so Runway 1R departures would be delayed. Exhibit D.3-14 Taxiways F and F1 Separation Alternatives In Alternative 4, Taxiway F would shift to a separation of 550 feet from Runway 10R-28L and Taxiway F1 would be realigned parallel at a separation of 800 feet from Taxiway F. This additional separation would prevent aircraft simultaneously crossing Runways 1L-19R and 1R-19L from converging at the intersection of Taxiways L and F. Aircraft movement simulations determined that this increased separation distance is necessary to ensure that aircraft crossing the runways on Taxiway F would have sufficient time to clear the Taxiway L intersection before an aircraft on Taxiway F1 turns onto Taxiway L and reaches the same intersection. Draft Final: September 2016 Appendix D Page 24 Draft Final: September 2016 Appendix D Page 23
Each alternative would shift the ADG VI OFA for relocated Taxiway F, southeast of Taxiway L, to the existing seawall. Taxiway F VSR Alternative 1 would relocate only the portion of the VSR located within the TSA. For the longer segment within the OFA, operational restrictions and additional signage and driver training would be required, as noted in Section 0. Taxiway F VSR Alternative 2 would relocate the VSR outside of the OFA, requiring the relocation of the seawall and affecting approximately 16,000 square feet of shore beyond the seawall. Exhibit D.3-15 depicts these two VSR alternatives. Exhibit D.3-15 Taxiway F Potential Roadway Modifications Taxiways F and F1 Separation Evaluation Table D.3-6 shows the evaluation matrix for the Taxiways F and F1 separation alternatives. All four alternatives include the relocation of Taxiway F to 550 feet from Runway 10L-28R to allow ADG VI aircraft to taxi unrestricted during Runway 28L CAT II ILS approaches. Alternatives 1 and 3 do not simplify operations in the area of the FAA hot spot and do not allow for simultaneous aircraft crossings of Runways 1R-19L and 1L-19R. Alternative 2 retains the existing Taxiway F1 non-standard runway-taxiway angle. These three alternatives were therefore eliminated. Although Alternative 4 has several moderate benefits as well as moderate impacts, it provides operational efficiency improvements while meeting FAA taxiway design guidelines. Alternative 4 was carried forward as a recommended alternative and combined with the FAA Hot Spot 1 alternatives (see Section 0) for inclusion in the recommended airfield development plan. FAA design standards indicate that the VSR may be located within the taxiway OFA, provided vehicle drivers are trained to yield to aircraft either by maintaining longitudinal separation or vacating the OFA. If the FAA requires this road to be located outside of the ADG VI taxiway OFA, modifications to the existing seawall and shoreline to accommodate a relocated VSR would result in significant environmental impacts. Therefore, VSR Alternative 1 is the recommended alternative. Draft Final: September 2016 Appendix D Page 25 Draft Final: September 2016 Appendix D Page 26
D.3.7 Taxiway T Runway Crossing To simplify the complexity of the intersections of Taxiway T with Taxiways D, K, and B, and to allow for the simultaneous use of Taxiways D and T by aircraft crossing Runway 10R-28L, four alternatives were developed to modify Taxiways T and D (depicted in Exhibit D.3-16). In all four alternatives, Taxiway T between Taxiways K and D would be removed or realigned, which would reduce the complexity of the intersections with Taxiway B. Table D.3-6 Evaluation of Taxiway F Alternatives In Alternative 1, Taxiway T would be realigned at the same exit angle from Runway 28R as Taxiway Q and cross Runway 10R-28L at a right angle. 6 This realignment would separate Taxiway T from Taxiway D and provide pilots with an easier view of the Runway 28L threshold. Taxiway D would be straightened across Runway 10R-28L and realigned Taxiways D and T and would be extended to Taxiway A. Existing Conditions Alternative 1 Alternative 2 Alternative 3 Alternative 4 Evaluation Criteria Realign Taxiway F north of Realign Taxiway F south of Realign Taxiways F and F1 Realign Taxiways F and F1 No Build Taxiway F1 Taxiway F1 with 324 separation with 800 separation Constructability/Phasing N/A Operational Efficiency Environmental Considerations In Alternative 2, Taxiway T would be realigned at the same exit angle from Runway 28R as Taxiway Q and the exit point would be shifted away from the Runway 28R landing threshold. Crossing Runway 10R-28L at a right angle, Taxiway T would continue onto the existing stub section of Taxiway D south of Runway 10R-28L. This alternative would remove the segment of Taxiway D between Runways 10R-28L and 10L-28R. Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative $27.5 million ($19.4 million Estimated Cost excluding shoreline) See FAA hot spot Recommended Airfield Development Plan alternatives Source: Ricondo & Associates, 2015 In Alternative 3, Taxiway T would be realigned at the same exit angle from Runway 28R as Taxiway Q, and the exit point would be shifted away from the Runway 28R landing threshold. Taxiways T and D would run parallel as they cross Runway 10R-28L, separated by 324 feet to allow simultaneous use by ADG VI aircraft. Alternative 4 includes a spiral exit taxiway design, originally developed by the FAA to increase taxiway centerline length between runways. This design would create a centerline radius for Taxiway T that would tighten as the aircraft exits the runway and approaches Runway 10R-28L. Similar to Alternative 3, Alternative 4 would be separated from a straightened extension of Taxiway D to meet ADG VI-ADG VI separation requirements of 324 feet. Draft Final: September 2016 Appendix D Page 27 6 The Taxiway Q exit taxiway design was preferred in a prior Runway Safety Action Team study. Draft Final: September 2016 Appendix D Page 28
Exhibit D.3-16 Taxiway T Alternatives Taxiway T Runway Crossing Evaluation Table D.3-7 shows the evaluation matrix for the Taxiway T runway crossing alternatives. The existing condition does not allow for dual simultaneous crossings on Taxiways D and T due to the taxiways intersecting on Runway 10R-28L. Alternative 1 was eliminated because the intersection with Taxiway B remains closer to FAA Hot Spot 1 than Alternatives 3 and 4. Alternative 2 would remove Taxiway D and relocate the Taxiway T exit point 380 feet farther from the Runway 28R threshold. Taxiway D is heavily used as an exit taxiway and its removal was not acceptable to SFO ATCT staff. Therefore, it was eliminated from consideration. Alternative 4 would reduce the length of an aircraft that can fit between existing hold position markings to 340 feet as compared to 480 feet for Alternative 3, a decrease of 140 feet. This separation is inadequate to hold aircraft between the runways, so it was eliminated. Alternative 3 would realign Taxiway T using the same geometry as existing Taxiway Q. This alignment is preferred because it allows pilots to view Runway 10R-28L to see oncoming aircraft. It provides sufficient separation for simultaneous independent operations on Taxiways T and D and provides flexibility for the FAA Hot Spot 1 alternatives. Therefore, Alternative 3 was carried forward into the evaluation of the FAA Hot Spot 1 alternatives. Draft Final: September 2016 Appendix D Page 29 Draft Final: September 2016 Appendix D Page 30
D.3.8 FAA Hot Spot 1 Remediation Five alternatives were developed to address the FAA hot spot (SFO-HS1) located at the convergence of Taxiways A, B, E, F, and J. These alternatives reduce complexity and the potential for pilot confusion in this area. All of the alternatives could work in conjunction with any of the Taxiway T alternatives but are dependent on certain Taxiways F and F1 alternatives as discussed below. Exhibit D.3-17 depicts Alternatives 1-4. Table D.3-7 Evaluation of Taxiway T Alternatives Evaluation Criteria Existing Conditions No Build Alternative 1 Alternative 2 Alternative 3 Alternative 4 Constructability/Phasing N/A Alternative 1 incorporates Taxiway F Alternative 4 (see Exhibit D.3-14) and removes exit Taxiway J to decrease the number of taxiway intersections along Taxiways A and B. The first opportunity for aircraft landing on Runway 28L to exit the runway would be on Taxiway E, 1,120 feet farther down the runway. The removal of Taxiway J would eliminate an additional pilot decision point and allow for clearer signage. The alignment of Taxiway F with Taxiways A and B would not reduce the possibility of runway incursions because access to Runway 1L-19R without a right angle turn would still be possible. Criteria Operational Efficiency Environmental Considerations Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $3.2 million Recommended Airfield Development Plan See FAA hot spot alternatives Source: Ricondo & Associates, 2015 Alternative 2 also incorporates Taxiway F Alternative 4 (see Exhibit D.3-14) and combines Taxiways E and J to reduce the number of taxiway intersections. This alternative would reduce to one the number of angled exit taxiways from Runway 28L and create a dependency between aircraft exiting Runways 28R and 28L at Taxiway E. Taxiway B would be reoriented to intersect Taxiway F at a right angle to provide a decision point for pilots from the south and east. The alignment of Taxiway F with Taxiway B would not reduce the possibility of runway incursions because access to Runway 1L-19R without a right angle turn would still be possible from the west. This alternative would allow for clearer signage and greater separation of taxiway centerlines. This alternative would also create better-defined shoulder areas and three-node taxiway intersections. 7 Under Alternative 3, the Taxiway B layout would be similar to the design in Alternative 2, but Taxiways F and F1 would shift south to reduce complexity and the possibility of runway incursions. A single Taxiway E perpendicular to Runway 10R-28L would replace Taxiways E and J. Near the intersection of Runways 10R-28L and 1L-19R, Taxiway B would make a 90-degree turn. Taxiway F and F1 would be separated by 324 feet and Taxiway F would be separated from Runway 10R-28L by 1,000 feet. A drawback of this alternative is the slower speed that would be required for aircraft taxiing through the 90-degree turn on Taxiway B. Similar to Alternative 2, the Alternative 3 layout eliminates taxiway intersections of more than three nodes. Draft Final: September 2016 Appendix D Page 31 Alternative 4 is similar to Alternative 1, but Taxiway B would be realigned with a larger, constant radius of 750 feet. Taxiway F would also be reconfigured with a slight turn to create a perpendicular intersection with Taxiway B and reduce the possibility of aircraft inadvertently entering Runway 1L-19R. Taxiway E would remain in the same location as Alternative 1 but could shift perpendicular to Runway 10R-28L as depicted in Alternatives 2 and 3. Taxiway J would be removed t o reduce the number of taxiway intersections. This alternative would also provide for only three-node taxiway intersections. 7 The three-node intersection concept never gives the pilot no more than three directional choices: left, straight, or right. Draft Final: September 2016 Appendix D Page 32
Exhibit D.3-17 FAA Hot Spot Taxiway Alternatives (1 of 2) Alternatives 1 through 4 involve the consolidation of Taxiways E and J south of Runway 10R-28L. However, SFO ATCT staff indicates that these taxiways are used heavily by arriving aircraft exiting Runway 28L, while Taxiway E is used frequently by arriving aircraft that exit Runway 28R and cross Runway 10R-28L. The analysis of aircraft movement data confirmed the heavy use of these taxiways. Therefore, to preserve the ability for arriving aircraft to exit Runways 28R and 28L efficiently, comparable exit points to Taxiways J and E would need to remain. Depicted in Exhibit D.3-18, Alternative 5 is similar to Alternative 4 but retains Taxiways E and J. Taxiway J would be realigned away from the intersection with Taxiway F and Taxiway E would shift away from Taxiway J. These realignments create greater distance between taxiway intersections with Taxiways A and B to allow additional time for pilot decision-making and provide clearer signage between intersections. Alternative 5 also incorporates Taxiway T Alternative 3 (see Exhibit D.3-16). This alternative would address the need for multiple runway exit taxiways while reducing the complexity of the hot spot. Exhibit D.3-18 FAA Hot Spot Taxiway Alternatives (2 of 2) Draft Final: September 2016 Appendix D Page 33 FAA Hot Spot 1 Remediation Evaluation Table D.3-8 shows the evaluation matrix for the FAA Hot Spot 1 remediation alternatives. The purpose of these alternatives was to reduce the complexity of the intersection, reduce the potential for pilot confusion, and meet current FAA taxiway design guidelines. Alternatives 1, 2, 3, and 4 result in the removal of an exit taxiway from Runway 10R-28L. SFO ATCT staff indicated that removing Taxiways E or J would reduce operational efficiency and an analysis of operational data confirmed that Taxiways E and J are used frequently during arrivals to Runways 28R and 28L. Draft Final: September 2016 Appendix D Page 34
Alternative 2 also creates an indirect access point where aircraft could inadvertently taxi onto Runway 1L-19R from Taxiway B. Alternative 3 mitigates that issue, but the relocation of Taxiways F and F1 away from the intersection places them at a closer separation, which would reduce the ability for aircraft to cross Runways 1R-19L and 1L-19R simultaneously. Because of these deficiencies, Alternatives 1 through 4 were eliminated from further evaluation. Alternative 5 incorporates the Taxiway T recommended alternative (Alternative 3) and the Taxiway F recommended alternative (Alternative 4). This alternative provides the same number of exit taxiways from Runway 10R-28L and realigns Taxiway E to the same angle as Taxiway Q. Alternative 5 would increase the radius of Taxiway B and incorporate larger islands between Taxiways A and B, allowing for more visible placement of taxiway signs. Taxiways E, J, and F would intercept Taxiways A and B at right angles, simplifying the intersection and enhancing pilot situational awareness. Alternative 5 would eliminate the ability of aircraft to cross from the terminal apron to the East Field. During weather conditions when aircraft must depart Runways 19L and 19R or when queuing for departure on Runway 10L, aircraft from the terminal area would be required to cross Runways 10R-28L and 10L-28R on Taxiways D or K. However, Alternative 5 was carried forward to the recommended airport development plan due to the safety improvements it would provide. Table D.3-8 Evaluation of FAA Hot Spot 1 Remediation Alternatives Evaluation Criteria Existing Conditions Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5 Combine Taxiways E and Remove Taxiway J, Combine Taxiways E and Realign Taxiways B, E, J, No Build Remove Taxiway J J, Realign Taxiway B, Realign Taxiways B and J, Realign Taxiway B F, and F1 Shift Taxiways F and F1 F1 Constructability/Phasing N/A Operational Efficiency Environmental Considerations Criteria Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $7.9 million (for E, J, and B modifications) Recommended Airfield Development Plan Source: SFO Bureau of Planning and Environmental Affairs, 2015 Draft Final: September 2016 Appendix D Page 36 Draft Final: September 2016 Appendix D Page 35
D.3.9 Helipad A helicopter landing marking located on Taxiway C near Taxiway R was removed in 2013 because it did not meet current FAA standard requiring that the center of helipad final approach and takeoff areas be located at least 700 feet from runways serving heavy aircraft (over 300,000 pounds). Over the past three years, Airport records show an average of 13 helicopter operations (takeoffs and landings) per day. SFO ATCT staff and Airport operations personnel indicated that the majority of helicopter activity is associated with the general aviation facilities located adjacent to the East Field aircraft apron. Exhibit D.3-19 depicts the four alternatives for a helipad in this area. In Alternative 1, a dedicated helipad would be located northwest of FBO Hangar B (Building 1050) and outside of the Taxiway C ADG VI OFA. Helicopters would land on this pad and hover taxi 8 onto Taxiway C to access the East Field aircraft apron. The center of the helipad would be located at least 747 feet from the nearest runway centerline. Under Alternative 2, the helipad would be located an additional 50 feet to the north to accommodate the OFA of a fully shifted Taxiway C (see Exhibit D.3-5). The helipad would be located at least 797 feet from Runway 10L-28R. Under Alternative 3, a helipad would be located on the northern edge of the East Field aircraft apron. This helipad would displace one aircraft parking position. Helicopters would hover taxi down the existing taxilane to access a parking position on the apron. To meet the 8:1 departure surface for helipads, modification to the adjacent aircraft operations area (AOA) fence would be necessary. Alternative 4 does not provide a helipad. Instead, SFO ATCT staff would guide helicopters to Taxiway Z between the taxiway entrance to the U.S. Coast Guard Air Station and Taxiway U. Based on the number of helicopter operations, this landing area may be sufficient for helicopters to land and hover taxi to their designated parking positions without interfering with other aircraft on these taxiways. Exhibit D.3-19 Helipad Alternatives Draft Final: September 2016 Appendix D Page 38 8 Hover taxi is a procedure where a helicopter follows taxiway markings while hovering lower than 25 feet Above Ground Level (AGL). Draft Final: September 2016 Appendix D Page 37
Helipad Evaluation Table D.3-9 shows the evaluation matrix for the four helipad alternatives. Alternatives 1 and 2 are located in the same area, but Alternative 2 was sited to accommodate a shifting of Taxiway C to a separation of 550 feet from Runway 10L-28R. This Taxiway C alternative was eliminated and therefore, Alternative 2 was eliminated because the additional setback from the taxiway is not required. Alternative 3 was eliminated because it resulted in the loss of a widebody aircraft parking position on the East Field apron and may require relocating the Police Main Training Facility and Shooting Range (Building 1059) located directly to the north. This alternative also required helicopters to hover taxi through the East Field apron, which may interfere with aircraft operations. Alternative 4 assumed operational changes that would require SFO ATCT staff to guide helicopters to a designated landing area at the intersection of Taxiway Z and the existing U.S. Coast Guard entrance. This location is difficult to view from the existing and future ATCTs. There is also the potential for helicopter pilots not familiar with the airfield to confuse the taxiways and adjacent U.S. Coast Guard apron. This alternative was eliminated from further consideration. Alternative 1 was selected as the alternative to be incorporated into the recommended airfield development plan. Table D.3-9 Evaluation of Helipad Alternatives Existing Conditions Alternative 1 Alternative 2 Alternative 3 Alternative 4 Evaluation Criteria No Build Criteria Constructability/Phasing N/A Operational Efficiency Environmental Considerations Impacts to Existing Facilities Compliance with Current FAA Standards and Guidelines Recommended Alternative Estimated Cost $300,000 Minimal Recommended Airfield Development Plan Source: SFO Bureau of Planning and Environmental Affairs, 2015 Draft Final: September 2016 Appendix D Page 40 Draft Final: September 2016 Appendix D Page 39
D.4 Recommended Airfield Projects The recommended alternatives were combined into a recommended airfield development plan that was then further refined based on input from the Airport, SFO ATCT, and FAA San Francisco ADO staff. Discussions with SFO ATCT and FAA ADO staff indicated a preference to relocate the centerline of Taxiway J away from the intersection of Runways 10R-28L and 1L-19R. Two further alternatives were developed based on the original recommended Hot Spot 1 remediation alternative. All three alternatives are depicted in Exhibit D.3-20. By reducing the radius of the Taxiway E centerline, Taxiway J can be shifted farther from the Runway 28L threshold and away from the runway intersection. Alternative 2 provides greater operational efficiency because the centerline radius for Taxiway J is greater, allowing aircraft to turn more gradually. This alternative was carried forward as part of the recommended alternative plan. Exhibit D.3-20 Revised Hot Spot 1 Taxiway Alternatives Exhibit D.3-21 Recommended Airfield Projects Exhibit D.3-21 depicts the refined recommended alternative plan. This plan was determined to meet taxiway design standards while continuing to provide the operational efficiency needed to accommodate future growth at the Airport. Draft Final: September 2016 Appendix D Page 42 Draft Final: September 2016 Appendix D Page 41