Northern Hills Homeowner's Association

The Revised Ricondo Recommendations

The Eleven Ricondo Recommendations Summary

II. Noise Abatement Measures

This section provides a description of the 11 noise abatement measures recommended for implementation at San Antonio International Airport. Information regarding program costs, financing, and implementation is provided in Section IV. Information and analysis of these and other noise abatement options considered for the Airport are provided in Appendix A.

2.1 Summary of Recommended Noise Abatement Measures

The 11 recommended noise abatement measures are:

1. Conduct live tests on noise abatement departure profiles consistent with FAA procedures to determine which would provide the most relief in terms of lowering the noise levels of individual aircraft departures from the various runways at San Antonio International Airport.
2. Pursue additional voluntary noise abatement procedures to further reduce noise levels of aircraft operations.
3. Establish a preferential runway use program that minimizes departures on Runways 12L, and 12R and arrivals on Runways 30L and 30R. To enhance the effectiveness of the preferential runway use program, extend Runway 3-21 to the northeast. In addition, extend Runway 12R-30L to the northwest, allowing for the removal of the intersection of Runway 12R-30L and Runway 3-21.
4. For departures from Runway 3, establish a departure corridor that places aircraft over compatible land uses east of Wetmore Road to the extent possible.
5. For those times that Runway 21 must be used for departure, establish a departure corridor that places aircraft over the Highway 281 corridor to the extent possible. (The preferential runway use program dies not include increased use of Runway 21, and it is assumed that departures from Runway 21 would represent about the same percentage of departures from the Airport as under current procedures. This measure is intended to provide noise relief during those times when Runway 21 must be used for departures.)
6. Incorporate the findings and recommendations of the engine run-up study into the FAR Part 150 Noise Compatibility Program.
7. Install and aircraft noise and operations monitoring system to track the use of departure corridors and departure profiles.
8. Enhance pilot awareness of noise-sensitive areas and noise abatement procedures by providing information for Jeppesen charts, airline pilot manuals, and fixed based operator information.
9. Investigate the use of noise barriers along Airport boundaries at runway ends to reduce the effects of takeoff roll noise.
10. Encourage Congress to seek stricter aircraft noise standards, particularly regarding a phase-out schedule for aircraft manufactured as Stage 2 that have been modified or are operated to meet Stage 3 noise standards.
11. Encourage the FAA to develop a phase-out schedule for FAR Part 36 Stage 2 aircraft weighing less than 75,000 pounds.

2.2 Descriptions of Individual Recommended Noise Abatement Measures

The following paragraphs provide a detailed description of each of the recommended noise abatement measures.

Conduct live tests of noise abatement departure profiles consistent with FAA procedures to determine which would provide the most relief in terms of lowering the noise levels of individual aircraft departures from the various runways at San Antonio International Airport.

Modifications to thrust and wing flap management procedures for departures are a proven means of reducing the noise levels generated by individual jet aircraft departures. Under these procedures, pilot typically depart at takeoff thrust, climb as quickly as possible to a safe altitude (usually 800 to 1,000 feet above the ground), reduce power and adjust flap settings, climb at a lower thrust setting for a specified period, and then resume a standard climb at climb thrust. Using such a procedure, the noise levels generated by an individual jet aircraft departure are lower that if a full-power climb to cruising altitude is followed. Most airlines already have defined standard departure procedures for the various aircraft in their fleets that are intended to reduce the noise levels of individual aircraft operations. However, the potential exists for further reductions in noise levels to be realized in noise-sensitive areas near the departure ends of runways if specific noise abatement departure procedures are followed.

Historically, specific departure procedures have been developed and implemented at some airports that are intended to achieve noise reduction goals at that airport. The most notable is the departure procedure implemented at John Wayne Airport in Orange County, California, in the 1980’s. The FAA, recognizing that the first segment of the departure climb is critical in terms of flight safety, and that departure procedures specific to individual airports could lead to too many different procedures that pilots would have to follow, decided to develop two standard noise abatement departure profiles that could be implemented at an airport.

FAA Advisory Circular (AC) 91-53A, Noise Abatement Departure Profiles, prescribes the parameters for two different abatement departure profiles (NADPs). One is intended to reduce noise levels closer to the airport (the close-in noise abatement departure profile) and the other is intended to reduce noise levels further from the airport (the distant noise abatement departure profile). Each airline has developed noise abatement departure procedures for each jet aircraft in their fleet consistent AC 91-53A, and submitted the procedures to the FAA to ensure that the procedures are safe and meet the requirements of AC 91-53A.

The potential for the implementation of the NADPs at San Antonio International Airport was considered as part of the FAR Part 150 Noise Compatibility Study Update. Because the specific procedures developed by each airline vary and because most of the airlines use one of the NADPs as a standard departure, it was difficult to determine the specific noise reductions that could be achieved. Also, because noise-sensitive land uses exist at different distances from the various runway ends, it was determined that the procedures that would provide the best benefit may be different depending on the departure runway.

Preliminary modeling indicated that implementing noise abatement departure procedures could reduce the noise levels of individual departures by three to six decibels. However, conversations with FAA Headquarters staff responsible for maintaining the INM indicated that the procedures identified for modeling the NADPs included in the INM manual can overstate the benefit of their use and the results are not reliable for estimating overall noise reduction. Accurately modeling the actual benefits associated with the NADPs at San Antonio International Airport would require a significant amount of time and a significant cost. Because each airline has developed the specific NADPs for each aircraft in their fleet, it would be necessary to develop a set of profiles for each aircraft type for each airline. FAA personnel further suggested that live testing and measurements of the benefits of the profiles might provide a more efficient means of selecting the better profile for each of the runway ends. After discussions with the TAC, it was determined that live testing of the NADPs would provide the best means for determining which of the profiles would provide the most effective noise relief from each of the runway ends at the airport. The use of NADPs from the runway ends meets each of the criteria listed in Section A.1. The live tests would determine which NADP provides the best relief in terms of single-event noise level reduction in noise-sensitive areas for each of the runway ends.

Therefore, after discussions with the TAC, it was decided that live testing of the procedures should be recommended as part of the updated Noise Compatibility Program. One airline representative on the TAC stated that, after a fair amount of testing and monitoring for their airline at a specific airport, it had been determined that the use of one of the NADPs for all runways would provide about the same overall noise level reduction and that the noise level reductions would be the same using either of the NADPs.

The recommendation is to test the AC 91-53A departure procedures from each of the runway ends and to determine which, if either, provides greater noise relief from each runway end. The objective of this measure is not necessarily to identify a specific procedure to be followed from each runway end, but to identify an achievable goal for noise reduction and to allow the air carriers to demonstrate that they could meet that reduction by using one of the noise abatement departure profiles. Under this measure, the profiles to be tested would be those that are compliant with FAA AC 91-53A.

Testing of the departure procedures would be conducted at different times of the year from each of the runway ends and a recommended NADP or noise level reduction from each runway end would be identified. The testing procedure would comprise collecting noise measurement data at several noise-sensitive locations under the departure paths for different aircraft types, with pilots following their standard departure procedure or one of the two NADPs. After comparing noise levels of different aircraft types following the different departure procedures, and reviewing land use data from each runway end, the procedure that generated the lowest noise levels in noise-sensitive areas from each runway end would be identified and the noise level reduction quantified. Final recommendations, developed after live testing, would identify the preferred NADP for each runway and the anticipated noise level reduction associated with the use of the procedure. The NADP selected for each runway would be required for use on that runway, unless airlines had demonstrated during the live testing period or through verified documentation for each aircraft that they operate at the airport that either of the NADPs would provide the same benefit in terms of noise level reduction.

The benefit that would be derived from the use of the NADPs is that single-event noise levels associated with departure operations would be reduced, particularly those of louder aircraft manufactured as FAR Part 36 stage 2 but modified to meet the requirements of FAR Part 36 Stage 3. The benefit would be realized in all areas around the Airport for departures from each of the runways. Therefore, the number of people exposed to aircraft noise of DNL 65 and higher would be expected to decrease. The single-event noise level reductions would also result in cumulative noise level reductions. In the absence of intensive modeling, which is outside the scope of this FAR Part 150 Noise Compatibility Study Update, the actual benefit cannot be quantified without the results of the live tests.

Pursue additional voluntary noise abatement departure procedures to further reduce noise levels of aircraft operations.

The only noise abatement departure procedures that can be identified as mandatory for a particular runway are the two NADPs defined in AC 91-53A as described above and as developed individually by the airlines for the aircraft in their fleets. However, further modifications to departures procedures have proven effective for further reducing aircraft noise exposure in noise-sensitive areas around airports. Airline representatives on the TAC stated that their companies had, on a voluntary basis, worked individually with airport sponsors to develop noise abatement procedures that provide even further noise reduction than that provided by use of the AC 91-53A NADPs.

Based on these discussions, the TAC decided that, after the testing of the AC 91-53A NAPDs and the identification of the preferred procedures and associated noise level reduction, it would be worthwhile for the Aviation Department to work with airlines to develop voluntary departure procedures that would further reduce noise levels associated with jet aircraft departures from each runway end.

The benefit that would be derived from the use of the voluntary procedures is that single-event noise levels associated with departures, particularly those of louder aircraft manufactured as FAR Part 36 Stage 2 but modified to meet the requirements of FAR Part 36 Stage 3, and therefore cumulative noise levels in noise-sensitive areas would be reduced. The benefit would be realized in all areas around the airport for departures from each of the runways. Therefore, the number of people exposed to aircraft noise of DNL 65 and higher would be expected to be reduced. In the absence of extensive modeling, which is outside of the scope of this FAR Part 150 Noise Compatibility Study Update, the actual benefit cannot be qualified.

Establish a preferential runway use program that minimizes departures on Runways 12L and 12R and arrivals on Runways 30L and 30R. To enhance the effectiveness of the preferential runway use program, extend Runway 3-21 to the northeast. In addition, extend Runway 12R-30L to the northwest, allowing for the removal of the intersection of Runways 12R-30L and Runway 3-21.

As shown on Exhibits I-4 and I-5, the noise-sensitive areas (including residential areas) exposed to the highest levels of aircraft noise associated with aircraft operations at San Antonio International Airport are located southeast of the airport. The only noise-sensitive areas exposed to DNL 75 and higher in 1998 and anticipated to be exposed to DNL 75 and higher by 2004 are southeast of the Airport. The area is affected by noise primarily from aircraft taking off on Runways 12L and 12R and aircraft landing on Runways 30L and 30R. Runway 12R is the longest runway at the airport and is oriented in a direction that is favorable with respect to the prevailing winds in the airport environs.

As described in the Noise Exposure Man Report, the runways available for departure and arrival are a function of the designated flow configuration at the Airport. Typically, prevailing wind and weather conditions determine the flow configuration at San Antonio International Airport and as other facilities in the region, such as Randolph Air Force Base, Kelly Air Force Base, and Stinson Municipal Airport. However, the actual runways that are used when the Airport is in a specific flow configuration are not always limited to those that are oriented in the direction of the flow configuration. Table II-1 provides a summary of the available runways for each of the four flow configurations at the Airport and the percentage of time that each of the flow configurations was in use during 1998.












Runway use data for 1998 showed that the actual runway use statistics for arrivals were fairly similar to the flow configuration, however the actual runway use for departures were somewhat different. The primary difference for departures was that when the airport was in southeast flow, a significant number of aircraft, including air carrier jet aircraft took off on Runway 3, which is designated as a secondary runway during a southeast flow.

For many air carrier departures, Runway 3 is favorable for takeoff compared with Runway 12R, without considering other factors. The taxi distance from the passenger terminal to the departure roll point for Runway 3 is significantly shorter than the distance from the passenger terminal to the departure roll point for Runway 12R, particularly for aircraft that are parked at Terminal 1. Also, because the majority of the aircraft departing the airport are headed to destinations north, northeast, or west of the airport, aircraft departing on Runway 3 are more likely to be headed toward their final destination sooner than if they had departed from Runway 12R. Consequently, even when the airport is designated to be in the southeast flow, a number of air carrier aircraft depart on Runway 3. The longer length of Runway 12R compared with Runway 3 and the orientation of Runway 12R to the southeast, the prevailing wind direction, do favor the use of Runway 12R for certain departures.

Table II-2 provides a summary of overall runway use by arrivals and departures by time of day for 1998 and 2004. Comparing runway use statistics with airfield flow configuration statistics, shows that the percentage of arrivals occurring on the various runways more closely corresponds with flow configuration percentages than do the departure percentages for various runways. As shown in Table II-2, approximately 53% of all aircraft that departed from San Antonio International Airport in 1998 took off on Runway 12L or 12R. About 54% of all air carrier jet aircraft that departed from the airport took off on Runway 12R. Also about 15% of all aircraft that arrived at the airport landed on Runway 30L or 30R, including 13% of all air carrier aircraft that landed on Runway 30L.











Because the highest number of noise-sensitive facilities are likely to be exposed to the highest levels of aircraft noise associated with departures on Runways 12L and 12R or arrive on Runway 30L and 30R, the TAC decided that it would be worthwhile to determine whether an even greater percentage of departures could occur on runways other than Runways 12L and 12 R and a greater percentage of arrivals could occur on runways other than Runways 30L and 30R.

A wind analysis was performed to determine what percentage of time wind conditions were such that it would be necessary for aircraft to depart on Runway 12L and 12R or arrive on Runway 30L and 30R. A criterion was used that aircraft would not depart on a particular with more than a 3-knot tailwind component or a 10-knot crosswind component. Ideally, aircraft depart and arrive with a headwind, or into the wind, with minimal crosswind. The tailwind and crosswind tolerances used for the analysis were those that were assumed would be acceptable by the predominant percentage of aircraft pilots who make the final determination whether a particular runway can be used, given the prevailing conditions.

The wind analysis showed that if a preferential runway use program under which Runways 12R and 12L would only be used for departure and Runways 30L and 30R would only be used for arrival when wind conditions required, a significant number of departures would likely occur on Runway 3 rather than Runways 12L or 12R, but that the use of the runways for arrivals would not likely change significantly. Further, the analysis showed that the use of Runways 21, 30L, and 30R for departures would not likely change significantly.

Runway length also affects runway use, particularly for departures. Runway 12R-30L, with a length of 8,502 feet, is the longest runway at the airport. Runway 3-21 is 7,505 feet long. Despite the longer taxiing distances between the passenger terminal area and the takeoff roll end of Runway 12R compared with Runway 3, pilots of some aircraft-primarily older aircraft and those with heavier fuel and passenger loads-departing the airport, particularly during periods of high temperatures, their current lengths, wind conditions alone would not dictate whether Runway 3 would be used for departure rather that Runway 12R. In some cases when winds would indicate that an aircraft could depart on Runway 3, the aircraft may still need to depart from Runway 12R, because of the additional length.

The Master Plan Update recommended that Runway 3-21 be extended 1,500 feet to the northeast to a total length of 9,005 feet to improve airfield capacity. This extension would also remove the length preference of Runway 12R for air carrier departures, and make wind direction the primary determinant of runway use.

Another airfield modification was reviewed as part of the study of abatement measures. The southeast end of Runway 12R-30L is at the eastern edge of Runway 3-21, resulting in the physical intersection of the two runways. Extending Runway 12R-30L approximately 400 feet to the northwest and decommissioning approximately 450 feet of the runway at its southeastern end-runways, allowing arrivals on Runway 12R and departures on Runway 3 to occur more independently. The combination of the extension of Runway 3-21 and the removal of the physical intersection of Runways 12R-30L and 3-21 would enhance the effectiveness of the preferential runway use program to reduce departures on Runway 12R.

Table II-3 provides a summary of the estimated potential runway use percentages if the preferential runway use program, the extension of Runway 3-21, and the removal of the physical intersection of Runways 12R-30L and 3-21 were all implemented.




The percentages presented in Table II-3 represent the highest level of reductions in the use of Runways 12R-30L and 12L-30R for departure. It is anticipated that the actual runway use change would be less than the runway use percentages above compared with the runway use percentages presented in Table II-2, would indicate. However, it is anticipated that a significant change in departure runway use could occur.

The text of the preferential runway use program would be developed in conjunction with local and regional FAA representatives and would include input provided by the airlines and Airport users. The program would be worded such that under normal operating conditions, Runways 12R and 12L would be used for departures only if the use of another runway would result in a tailwind component of more than 3 knots or a crosswind component of more than 10 knots. Likewise, Runways 30L and 30R would be used for arrivals only if the use of another runway would result in a tailwind component of more than 3 knots or a crosswind component of more than 10 knots. As with any noise abatement procedure, the program description would include appropriate language regarding runway closure, prevailing conditions, aircraft safety, and pilot discretion.

The primary benefit of the preferential runway use program, in terms of noise reduction, would occur in areas southeast of the airport, particularly in the areas southeast of the airport but north of Loop 410 that are exposed to the highest levels of aircraft noise in the airport environs. The Aviation Department and the TAC recognized that simply shifting the departure runway use patterns would generate significant increases in noise exposure in areas north of the airport that are affected by departures from Runway 3. However, based on a review of existing land use and zoning an area of compatible land use was identified that could provide a corridor that would prevent aircraft departing from Runway 3 from flying directly over residential areas near the northeast end of Runway 3-21. The Aviation Department and the TAC therefore decided that the preferential runway use program, in combination with the development of a departure corridor that could be used by Runway 3 departures would provide the greatest benefit to airport neighbors southeast of the airport without placing undue increases in significant noise exposure in areas north of the airport. The departure corridor (described in the following measures) and the preferential runway use program are therefore combined measures, so they would be pursued together. If for some reason, the departure corridor from Runway 3 could not be implemented or could not be used by a significant number of aircraft, or if some other means of minimizing the adverse effects north of Runway 3-21 could not be identified, the City of San Antonio would not pursue the preferential runway use program as described, without pursuing another means of noise abatement for areas north of Runway 3.

Approval of this recommendation by the FAA, as part of the updated Noise Compatibility Program, would allow the Aviation Department to request federal funds to pursue a preferential runway use program along with the noise abatement departure corridor described below or some other form of noise abatement that would prevent significant increases in noise-sensitive land uses exposed to significant aircraft noise north of the airport. Approval of this recommendation by the FAA, as part of the updated Noise Compatibility Program, would not allow the Aviation Department to implement the program without additional planning and environmental studies. Several variables regarding air traffic control considerations, the potential effects of overflights in areas north of the airport, and the ability to implement appropriate abatement for those overflights north of the airport that were outside of the context of the FAR Part 150 Noise Compatibility Study Update must be addressed and must meet FAA approval prior to the implementation of the preferential runway use program. The potential noise reduction benefits of the preferential runway use program, combined with the Runway 3 departure corridor are described as part of the next measure.

For departures from Runway 3, establish a departure corridor that places aircraft over compatible land uses east of Wetmore Road to the extent possible.

Areas northeast of the airport but west of Wetmore Road are exposed to the next highest levels of aircraft noise (after the area southeast of the airport) under current operating conditions. These areas are primarily affected by overflights of aircraft departing on Runway 3. As demonstrated in the –preliminary analysis of the preferential runway use program, noise exposure in noise-sensitive areas would be significantly increased of the runway use program were implemented without other noise abatement measures. A review of existing land use and development shows that the area northeast of Runway 3-21 and east of and adjacent to Wetmore Road is either underdeveloped or developed in uses that are compatible with aircraft noise as far as Thousand Oaks Drive. The compatible land use provides a potential corridor for aircraft to follow after departing on Runway 3. To follow the corridor, pilots generally initiate a turn of approximately 15 degrees to the right as soon as possible after taking off from Runway 3 and then turn back to the left to the runway heading after crossing Wetmore Road to overfly the compatible land use. Upon reaching the area near Thousand Oaks Drive, it is assumed that pilots would turn toward their enroute paths to continue toward their destinations. Exhibit II-1 provides a general depiction of the intended flight corridor as compared with the existing flight corridor followed by aircraft departing from Runway 3. The potential noise abatement departure corridor would appear to provide positive benefits in terms of reducing the number of residences and other noise-sensitive facilities that would be exposed to aircraft noise of DNL 65 and higher, particularly if the preferential runway use program is implemented. However, concerns have been raised in terms of (1) the affects of overflights in areas northeast of the airport which are not currently receiving a large number of overflights, and (2) potential effects on operations at the airport. Although this procedure shows potential noise abatement benefits to noise-sensitive areas based on initial review and analysis, additional detailed study of the procedure is required to fully assess and identify means to minimize the effects (1) associated with the potential for new overflights of noise-sensitive areas and (2) on airport operations. This type of analysis is typically performed as part of an Environmental Assessment (EA) or an Environmental Impact Study (EIS), and is outside of the scope of this FAR Part 150 Noise Compatibility Study Update. An EA or an EIS would have to be performed prior to implementation of mandatory flight track changes associated with this type of departure procedure.

As depicted on Exhibit II-1, the new departure corridor from Runway 3 would, for the most part, place aircraft over compatible land uses east of Wetmore Road for the initial portion of the climb after takeoff until reaching the area just north of Thousand Oaks Drive, thereby reducing the noise levels of individual aircraft departures as well as cumulative noise levels in most noise-sensitive areas west of Wetmore Road north of McAllister Park, which are currently exposed to aircraft noise levels of DNL 65 and higher and in some cases, DNL 70 and higher. As shown on the updated noise exposure map for 2004, Exhibit I-5, a large area of residential and other noise-sensitive land uses in this area would be exposed to significant aircraft noise levels even if the preferential runway use program is not implemented.

In the preliminary review of the procedure, it was assumed that aircraft would begin their turn toward their destination approximately upon reaching the Thousand Oaks drive. A review of FAA radar data completed during the preparation of the noise exposure maps, as documented in Volume 1 of this study report, showed that under current operating procedures, aircraft departing from Runway 3 and following the runway heading begin to turn to follow the course toward their destination beginning at or just north of Thousand Oaks Drive. However, until full airspace review of the procedures has been conducted and the means for providing guidance for the turn procedure are in place, the specific location where aircraft would begin their turn toward their destination cannot be fully determined. Consequently, the exact areas of overflights and the associated noise cannot be definitively determined until the airspace review is completed. However, based on the preliminary review it is not anticipated that a large number of residential or other noise-sensitive uses would be exposed to aircraft noise of DNL 65 and higher in the areas north of the Northern Hills Golf Course. It is also likely that the corridor could also be defined to minimize overflights of noise-sensitive uses in the area. Therefore, although concerns regarding changes in noise exposure must be addressed in order to implement the turn procedure, it is anticipated that adequate noise abatement and noise mitigation could be established to minimize potential adverse effects through the environmental process that would be required to implement the procedure.

During discussions with the TAC , FAA Airport Traffic Control Tower and Terminal Radar Approach Control (TRACON) personnel, concerns were raised regarding the ability for all aircraft departing Runway 3 to follow the corridor. The concerns were primarily with regard to the potential (1) for effects on runway capacity at San Antonio International Airport of requiring all aircraft departing from Runway 3 to turn right and follow the curved departure path and (2) for airspace conflicts associated with turning aircraft departing on Runway 3 from San Antonio International Airport toward traffic patterns at Randolph Air Force Base located east of the airport.

FAA procedures require that minimum horizontal or vertical separations be maintained between aircraft operating in the airspace. Horizontal separation between aircraft refers to the distance between the locations of the aircraft if projected onto the ground. Vertical separation between aircraft refers to the difference in altitude between the aircraft. Just after takeoff and in the initial segments of the climb, air traffic controllers can only rely on horizontal separations to maintain safe operating distances between aircraft. The two primary means for providing and ensuring the appropriate horizontal separations between aircraft departing from the same runway are to (1) assign aircraft to routes that result in courses that diverge (in other words, the aircraft will move further and further apart as they continue their flight) or (2) ensure that adequate separation exists between aircraft on the same route that the trailing aircraft does not catch up with the leading aircraft. The former method is the more common, particularly for maintaining separations between slow and fast moving aircraft after departure.

The fleet mix of aircraft operating at San Antonio International Airport, and therefore departing from Runway 3, includes a wide range of aircraft with differing operating characteristics, including varying speeds. FAA controllers told the TAC that currently, they direct jet aircraft to follow the runway heading after taking off from Runway 3, while lower performance propeller-driven aircraft are turned to the right and left shortly after takeoff from Runway 3. Turning the propeller-driven aircraft to the right and left while maintaining the jets on the runway heading ensures the necessary horizontal separation between the faster aircraft and slower aircraft. FAA controllers stated that if all aircraft were all required to follow the same path, controllers would have to hold a jet aircraft departing behind a slower, propeller-driven aircraft on the runway until the slower aircraft had traveled far enough so that the jet would not get too close behind the propeller aircraft in the air before the two aircraft could be turned on different courses or until the altitude separations were great enough to prevent an airspace conflict from occurring. Therefore, local FAA controllers are concerned that the number of aircraft that could depart from a given runway over a specific time period would be reduced, because more time between departures would be required. A detailed analysis or computer simulation would be required to accurately assess the impacts of the procedure with respect to airfield capacity and aircraft delay. Such an analysis would be performed as part of an EA or EIS. Further discussions with the TAC resulted in the recommendation that the procedure be pursued, but the controllers have the option for some jet aircraft to fly straight out along the runway heading after taking off from Runway 3.

Another concern raised by the local air traffic control representatives was that any right turn by jet aircraft after departure from Runway 3 at San Antonio International Airport would increase the potential for airspace conflicts with aircraft landing at Randolph Air Force Base located east of the airport. The potential for airspace conflicts could also prevent all aircraft from being turned to follow the proposed corridor.

Therefore, the recommendation is to establish a corridor that would allow aircraft to overfly compatible land uses east of Wetmore Road after departing from Runway 3. It has been beyond the scope of this FAR Part 150 to prescribe the specific corridor and the full extent to which it could be used. To establish and implement the corridor, the following steps, at a minimum would be required;

 Identify the preferred corridor and the procedure by which aircrews would be guided on the course.
 Identify navigational aid requirements and cost estimates for establishing the appropriate procedures.
 Perform airspace and noise analyses to refine the desired corridor and to estimate the types of aircraft and the percentage of aircraft that would likely be able to follow the corridor. (The analysis would result in a definition of how the corridor would be used, e.g., by certain aircraft types, by time of day (day or night), by weather conditions, etc.)
 Develop the proposed language to be included in the FAA Airport Traffic Control Tower manual to describe the procedure and its use.
 If after the above tasks are completed, it is decided to implement the procedure, prepare an EA of the proposed procedure. (It is anticipated that the EA would address the combined effects associated with the preferential runway use program, the potential extension of Runway 3-21, and the proposed noise abatement departure corridor.)

The results of the preliminary analysis of the potential benefits of implementing the combined preferential runway use program and the departure corridor are depicted on Exhibit II-2. The noise contours depicted include the noise exposure associated with the program measures plotted on the same base map with the 2004 noise exposure map. The analysis was conducted assuming (1) the maximum potential use of the preferential runway use program (i.e., the assumed greatest potential shift of departures from Runways 12L and 12R to Runway 3 and (2) that all jet aircraft departing from Runway 3 would turn just after takeoff and follow the potential noise abatement corridor east of Wetmore Road. The potential benefits in terms of the reductions in the number of residential units and population exposed to significant noise levels are summarized in Table II-4. Also shown in Table II-4, for comparison purposes, are the impacts associated with the 1998 noise exposure.

As shown in the table, the implementation of both measures (the preferential runway use program and the Runway 3 departure corridor) could result in a decrease of 910 households and 2,170 people exposed to DNL 65 and higher, compared with the 2004 noise exposure map. Of even greater significance are that there would be no dwelling units or people exposed to DNL 75 and higher and that a decrease of 720 dwelling units and 1,230 people exposed to DNL 70 and higher could occur compared with the 2004 baseline noise exposure map.



















Again, it should be noted that the results reflect the greatest potential change in runway use as a result of the preferential runway use program and that all jet aircraft departing from Runway 3 would follow the noise abatement departure corridor. Although the full benefits described in Table II-4 may not occur as a result of the implementation of the recommended measures, it is clear that the measures have the potential for providing significant reductions in aircraft noise exposure, particularly in those noise-sensitive areas that are exposed to the highest levels of aircraft noise in the environs of San Antonio International Airport.

The City of San Antonio recognizes that additional study and review would be required to implement the preferential runway use program and the departure corridor from Runway 3. Therefore, the City requests that the measure be approved as part of the noise compatibility program to be eligible to receive federal funding to pursue the measures and to perform the necessary analyses and environmental studies to implement the measures if proven to be feasible and prudent.

For those times that Runway 21 must be used for departure, establish a departure corridor that places aircraft over the Highway 281 corridor to the extent possible.

Currently, only about 3% of all departures from San Antonio International Airport take off on Runway 21 and it is not anticipated that this percentage will change, because of the typical weather patterns, as well as ground taxiing and airspace constraints that limit departures from the runway. Even if the recommended preferential runway use program described above were implemented, it is not anticipated that there would be any percentage increase in the use of Runway 21 for departure, again because of the taxiing, weather, and airspace constraints.

Although the departures on Runway 21 represent only a small percentage of the departures from the airport and only a small area of noise-sensitive land uses south of the airport was exposed to aircraft noise of DNL 65 and higher in 1998, residential areas near the south end of the runway are exposed to fairly high single-event noise levels when aircraft depart from Runway 21. A review of the land use patterns south of the airport shows that it may be possible for aircraft to execute a slight turn to the east shortly after takeoff from Runway 21 and to follow a course that roughly follows the alignment of Highway 281 to the south.

Although the final benefit cannot be quantified without knowing the final alignment of such a track, it is anticipated that the single-event noise reductions of three to five decibels could be realized in noise-sensitive areas south of and fairly close to the airport that experience the highest single-event levels. The recommendation is to work with FAA Airport Traffic Control Tower personnel and airline representatives to pursue the development of a procedure for departures from Runway 21 that would place departing aircraft on a route that generally follows Highway 281 to the south. As part of the development of the procedure, modeling would be conducted to ensure that other noise-sensitive areas would not be exposed to undue single-event noise levels if the procedure were implemented.

Incorporate the findings and recommendations of the engine run-up study into the FAR Part 150 Noise Compatibility Program.

The City of San Antonio Aviation Department recently completed an assessment of the benefits of constructing a ground run-up enclosure (GRE) as documented in a summary report prepared in May 1999. The study of the benefits of, and the design of the GRE were funded using federal funds for which the City became eligible to receive through an approved amendment to original Noise Compatibility Program. As documented in the summary report, all of the homes currently or anticipated to be exposed to significant noise levels from ground run-ups (using the criteria described in the report) would no longer be exposed to significant noise levels if a GRE were constructed at the airport. The City of San Antonio has subsequently received funding from the FAA to construct the GRE. Construction is scheduled to begin in Fall 2000, with completion in late Summer, 2001.

The City of San Antonio requests that the implementation of the GRE become an official measure of the noise compatibility program for the airport. The City is not requesting eligibility for additional funds for implementation. The recommended measure is therefore administrative in nature and approval would not make the City eligible for additional federal funds.

Install an aircraft noise and operations monitoring system to track the use of departure corridors and departure profiles.

An important element of a noise compatibility program is the monitoring of progress toward implementation. Administrative means can be used to monitor implementation of some measures (e.g., monitoring of noise complaints, use of quieter aircraft). However, the monitoring of the implementation of certain types of measures requires the continual collection of data regarding the noise levels of individual aircraft operations and the trajectories (flight paths and altitude profiles) of individual aircraft operations. Such data can be collected using a permanent aircraft noise and operations monitoring system. Aircraft noise and operations monitoring systems can be used to measure.

 Individual aircraft noise levels.
 The aircraft type of specific operations.
 Runway use.
 Flight track definition and use.
 Daily and annual DNL levels at various locations around the airport.

Permanent aircraft noise and operations monitoring systems typically include:

 Several permanent noise monitoring stations located in the airport environs.
 One or more portable noise monitoring units that can be placed in the field for short periods of time to address specific needs.
 Connections to FAA radar data to allow ongoing monitoring of aircraft operations and in some cases correlation with individual noise events
 A system for registering and responding to aircraft noise complaints, including (in some cases) the ability to correlate noise complaints with specific aircraft operations and associated noise levels at the nearest monitoring station.
 Central data management and display system, including mapping capabilities, typically using geographic information system (GIS) technology.

Such ongoing information at San Antonio International Airport would be valuable in terms of monitoring:

 Cumulative and individual aircraft noise levels.
 Runway use.
 Noise abatement departure profile use.
 Preferential runway use program implementation (if approved and implemented).
 Noise abatement flight track use (if approved and implemented).

The implementation and success of several of the measures that have been recommended herein could best be monitored using such a permanent aircraft noise and operations monitoring system. A permanent noise and operations monitoring system would also allow the Aviation Department’s Noise Mitigation Office to respond to aircraft noise complaints with specific information regarding the operation(s) that generated the noise disturbance and to potentially identify ways to reduce the occurrence of excessively high noise levels from individual operations within noise-sensitive areas. Such a system would also allow the Noise Mitigation Office to provide more detailed information in the form of data and reports to the airport’s Noise Abatement Advisory Committee (NAAC). The NAAC was formed as a recommendation of the original FAR Part 150 Noise Compatibility Study, approved in 1991.

The City of San Antonio Aviation Department requests that the measure be approved to allow the City to be eligible for federal funding to develop specifications for and to acquire and implement a permanent aircraft noise and operations monitoring system. As part of the original FAR Part 150 Noise Compatibility Program, The Aviation Department acquired and used portable noise monitoring units to measure noise levels on a short-term, case-by-case basis. This measure would enhance the current noise measurement efforts.

Enhance pilot awareness of noise-sensitive areas and noise abatement procedures by providing information for Jeppesen charts, airline pilot manuals, and fixed based operator information.

Another important element of a noise compatibility program is user information and education. For noise abatement measures to be most effective, all users must be aware of (1) where noise-sensitive areas are located and (2) the specific noise abatement measures that are in place. A variety of means are available for airport sponsors to provide the necessary information to airport users, including:

 Descriptions of noise-sensitive areas and noise abatement measures in published airport approach information, such as that available through Jeppesen Sanderson.
 Publication and distribution of noise-sensitive area maps and noise abatement procedures descriptions to all airport users, through airlines, fixed base operators, and other airport tenants.
 Development of educational materials to be provided to airlines and other aircraft operators to instruct pilots regarding noise-sensitive areas and noise abatement procedures pertinent to the airport.
 Construction of airfield signage to instruct pilots regarding noise abatement procedures as appropriate.

Although the specific benefits of this measure in terms of reductions in the number of people or households exposed to significant levels of aircraft noise cannot be quantified, benefits would be realized in terms of greater pilot awareness of noise-sensitive areas and noise abatement measures. In other words, the benefits derived from this measure would be through greater understanding by aircraft pilots of noise exposure in the airport environs and of the measures intended to reduce noise exposure.

The City of San Antonio Aviation Department has already provided information for published airport approach procedures that are available to aircraft pilots. In addition, airfield signage was installed in the early 1990s, advising pilots to “follow noise abatement procedures”, however more specific language may be beneficial as new procedures are implemented. The City requests approval of this measure to be eligible to receive federal funding as needed to implement additional means for making pilots aware of the noise abatement program. The types of programs for which the City might request funding would include development of publications, educational materials, and modifications to existing airfield signage.

Investigate the use of noise barriers along airport boundaries at runway ends to reduce the effects of takeoff roll noise.

Noise barriers have been demonstrated to provide noise relief in areas near an airport that are exposed to significant noise from departure back blast and in some cases arrival thrust reversal procedures. Although the specific benefits that could be gained through the development of noise barriers could not be assessed within the scope of the FAR Part 150 Noise Compatibility Study Update, the TAC and the Aviation Department recognize the potential for noise reduction using noise barriers to be achieved, particularly in areas near the southern end of Runway 3-21, the southeastern end of Runway 12R-30L, and the northwestern end of Runway 12R-30L. The potential benefits would be associated reductions in cumulative noise levels in the areas near the runway ends as noted above. Although the number of households and people that would experience reduced noise levels cannot be quantified at this time, those that would experience reductions are those closest to the airport that are exposed to the highest levels of aircraft noise.

The City of San Antonio Aviation Department requests that the measure be approved to allow the City to be eligible for federal funding to identify the potential benefits that could be gained from noise barriers, and if found to be beneficial, develop specifications for constructing the barriers. The measure is similar to the approved measure in the amended program that allowed the City to obtain federal funds to investigate the benefits from and to develop recommendations regarding the construction of a ground run-up enclosure as described above. If found to be beneficial, the City would then submit an amendment to the FAR Part 150 program to become eligible for funding to construct barriers in those locations that would provide noise relief in the neighborhoods around the airport.

Encourage Congress to seek stricter aircraft noise standards, particularly regarding a phase-out schedule for aircraft originally manufactured as Stage 2 that have been modified or are operated to meet Stage 3 noise standards.

The noise levels of aircraft operating in the U.S. are regulated by Federal Aviation Regulations (FAR) Part 36, “Noise Standards, Aircraft Type and Airworthiness Certification”. As of January 1, 1985, only aircraft that met FAR Part 36 are referred to as the Stage 3 Standards. The Airport Noise and Capacity Act of 1990 (ANCA) mandated that the FAA develop a schedule for standards. In response, the FAA established the phase out schedule for aircraft weighing more than 75,000 pounds (representing nearly all air carrier jet aircraft) through an amendment for FAR Part 91, “General Operating and Flight Rules,” stating that after December 31, 1999, Stage 3 noise standards could be operated at U.S. airports. Again, the phase out schedule only applied to aircraft weighing more than 75,000 pounds.
Aircraft operators were given the option of replacing the aircraft in their fleets with aircraft manufactured to meet the Stage 3 standards or modifying aircraft in their fleet to meet the Stage 3 standards. Because of the high costs of acquiring new aircraft as well as the limited availability of new aircraft, many aircraft operators chose to modify a portion of their fleet that did not meet the Stage 3 standards using hushkits or other methods so that the aircraft could meet the Stage 3 standards.

The Aviation Department and the TAC recognized that the phase-out of the modified Stage 2 aircraft could further reduce noise exposure in the airport environs. The level of reduction could be similar to that noted by comparing the 1998 and 2004 noise exposure maps presented in Exhibits I-4 and I-5, which illustrates the effects of the phase out of Stage 2 aircraft. Therefore, as a measure of the Noise Compatibility Program, the City of San Antonio will encourage Congress to seek more stringent aircraft noise standards that would eventually lead to the phase out of the modified Stage 2 aircraft. The City is not seeking eligibility for funds to seek the more stringent noise standards, but desires to officially indicate its intent to encourage Congress to work toward this goal.

Encourage the FAA to develop a phase-out schedule for FAR Part 36 Stage 2 aircraft weighing less than 75,000 pounds.

As stated for the previous measure, the phase-out of FAR Part 36 Stage 2 aircraft only applied to aircraft weighing more than 75,000 pounds, although ANCA clearly specified that the FAA should also develop a phase-out schedule for Stage 2 aircraft weighing less that 75,000 pounds. As the air carrier fleets have become quieter, the noise environments around airports are controlled more and more by corporate and general aviation jet aircraft, because these aircraft generate noise levels as high as those generated by many Stage 2 air carrier jet aircraft.

The development of a phase-out schedule for Stage 2 aircraft weighing less than 75,000 pounds has proven difficult because of the economics of the operators of these aircraft. Typically, these operators own and operate one or only a few aircraft and the costs associated with replacing these aircraft would be significant relative to the overall operating costs. Also, because the fleet of aircraft weighing less that 75,000 pounds comprises such a large number of aircraft types with different engine types, the economies of developing hushkits or other modifications are quite different than for the air carrier fleets. Finally, the aircraft are typically not operated as frequently and are not subjected to the same number of landing and takeoff cycles as most air carrier aircraft. As a result, the aircraft have a longer usable service life and would not need to be replaced as frequently as air carrier aircraft. Regardless, Congress should mandate that the FAA develop a phase-out schedule for the smaller jet aircraft.

The Aviation Department and the TAC recognize the importance of developing the phase-out schedule for the smaller aircraft, which would provide noise reduction benefits for all areas in the airport environs. The City of San Antonio is not requesting eligibility for funding to seek the phase-out of Stage 2 aircraft weighing less than 75,000 pounds, but desires to officially indicate its intent to encourage the FAA to develop such a phase-out schedule.

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