Study Group Meetings

February 14, 2000

MEMORANDUM

TO: LFA/Bill Willkie, Project Manager

FROM: 150 Study Group/Lt Col Tom Marks, Chair

SUBJECT: Noise Abatement Strategies

The attached noise abatement strategies are a consolidation of measures approved for analysis by the 150 Study Group at its February 3 meeting, based on suggestions from your October 15 presentation; refinements or additions put forward by the Study Group’s various committees and adopted on December 7; and feedback furnished in your presentation of January 13.
The Study Group is guided, as before, by its aims to:

• reduce noise contours

• leverage technology

• make flight patterns more consistent, hence more predictable

• reduce exceptions to standard procedures

• keep information affecting airport operations accessible to the public

• respect operational needs and regulatory imperatives

The discussion attached here is an effort to make a complete account and disposition of measures previously adopted, and lay out an experimental design that achieves the most robust coverage for the resources available. But the Study Group fully recognizes the criticality of this phase of the study; so it’s important to emphasize some key aspects of near-term activity that will make or break the effort. These include:

• Precise, mutually understood composition of each strategy. To insure fidelity of the design and implications of results, no uncertainties should remain about measures included or excluded; how measures are represented for analysis; or interdependencies arising in the analysis. Rationale must remain clear throughout, and follow-on documentation planned and previewed to preserve the consensus of the group.

• Close - intimate - communication on analysis. The Study Group needs a clear view of critical inputs developed for modeling—flight tracks, placement of navigational aids, and the like—to avoid surprises and prompt any necessary course correction. Emerging insights must be relayed right away, and anomalies identified for further review.

• Precise definitions of key terms. Some key examples that have already led to woe in discussions and policy reviews to date:

"preference/preferential use"

"peak/non-peak"

"voluntary measure"

• Open-ended review of results. Broad discussion of the substance and implications of the analysis are essential to an enriched ‘package’ that directs results to specific local needs. Assumptions and conclusions must be challenged at every turn to confirm their rigor, with ongoing feedback directed to refining and improving them.

In short, work in this phase is crucial to study results. "Oops" is consequently no longer an affordable part of the vocabulary.
Should any of the Study Group’s noise abatement strategies require elaboration beyond that provided in the attached discussion, please contact me without hesitation. We look forward to your consultation in moving this process forward.

February 14, 2000

Noise Compatibility Study Group

Noise Abatement Strategies, as Approved

The strategies outlined below are for detailed analysis in support of the Louisville Noise Compatibility Study. For purposes of economy, each of the three principal alternatives combines measures oriented on abatement north, and in turn south, of the airport. They are not paired in any self-conscious way; on the contrary, effects of these measures north and south of the airport will have to be disaggregated as clearly as possible to permit meaningful choices for each case.

Measures anticipated as net benefits in any scenario become common elements of each strategy. Our understanding is that the marginal contribution of any of these measures can be isolated as required in a post-processing phase of the analysis.

In sum, the noise abatement strategies laid out here vary according to runway use. To the north, the strategies vary according to runway preference; to the south, according to runway divergence. Common measures, in turn, aim to reduce noise exposure further through optimal orientation of, and minimal deviation from, flight tracks; application of available operational, physical, regulatory, and management measures; and documentation of emerging technologies and practices that may mature for future consideration.

Common elements

• Minimize contraflow exceptions. Postulate procedures that would direct scheduled flights during contraflow periods into conforming patterns, by rescheduling; leveraging the interim between arrival and departure periods; proposing additional pauses during these periods; or other means to direct all operations but emergencies to the south during the contraflow period.

• Determine and apply noise-optimal prescribed flight tracks (STARs, SIDs) for all six runways (11, 17L, 17R, 29, 35L, 35R). Combine detailed knowledge of practical flight operations and local population distribution to plot routes for arrivals and departures that yield minimum noise exposure to populated areas. Observe currently prescribed minimum runway divergences, except where otherwise indicated below. Incorporate considerations of simultaneous operations; elevation of affected neighborhoods; and restricted airspace around Fort Knox. Provide for minimal exceptions from prescribed tracks, in cases of pilot-declared emergency, weather extremes and the like.

• Apply required navigational performance standards (RNP), or hardware specifications, to minimize deviation from prescribed flight tracks. Develop and apply the strictest standard that can reasonably be imposed on users of the airport with available technology to insure fidelity to prescribed routes.

• Operational measures (potential excursions). Apply such constraints as are necessary to insure that prescribed flight tracks are used consistently in non-emergency situations, and to the best effect. Visual approach clearances, for example, should not permit deviation from prescribed tracks, but only add flexibility to factors like delayed flap and gear extension that would further reduce noise exposure. Thrust procedures, if practicable, should be applied uniformly, to avoid complicating the tasks of pilots using the airport.
Of the remaining measures proposed in these categories, detailed analysis should include

Higher holding and maneuver altitudes, in particular as required to compensate for increased elevation of selected areas

Steeper glide slopes and two-stage approach procedures, as required to compensate for increased elevation of selected areas

Use prospective runway extension for takeoffs (2005 case)

• Facilities, use restrictions, and regulatory measures. Specific measures endorsed by the Study Group include

Postulate placement and use of whatever navigational aids are necessary to support arrival and departure tracks (STARs, SIDs) developed above

Assign displaced arrival thresholds where runway length exceeds that required for safe operations, including prospective runway extension

Require conformance with noise compatibility program by all aircraft unless specifically excepted (advise recommended exceptions)

Define and apply feasible limits based on event metrics (e.g., so many operations permitted to exceed an SEL of X dB in a given period) (advise specific recommendations)

Continue, and propose means to expand, restrictions on engine run-ups

• Management measures.

Establish airport noise office

Form community noise forum

Maintain and expand study Web site and public information centers

Conduct selective ongoing noise monitoring

Collect and analyze ongoing flight track data

Conduct periodic in-house modeling to estimate current noise exposure

• Document knowledge of ‘emerging’ measures. Education of all affected constituencies, and a robust implementation program poised to take advantage of new developments, are central goals of the study effort. It’s therefore important that study reporting include all available information on any measures deferred in the present program because of practical or technological developments that are not yet mature. This knowledge base will permit orderly revisitation and further consideration of these measures as their maturation warrants. Specific measures endorsed by the Study Group that preliminary assessment places in this category include:

Advanced navigation aids (laser homing, microwave landing systems, military-specification GPS equipment, "ADS-B")

Counter-frequency generators

On-site exterior sound absorption media

Next-stage engine technology

Principal alternatives

• Limit east runway preference to daytime only. For modeling, retain current runway use frequencies during the day (7AM–10PM), but change nighttime frequencies to approximate equal use of both runways. Make initial array based on destination; advise if further steps necessary to achieve parity. Manipulate STARs and SIDs to minimize noise exposure of affected populations.

Apply southbound divergence according to destination (as currently). Assign eastbound flights on runway 17R a SID based on runway heading, and further plotted to minimize exposure of affected populations. Report implications for avoidance of Fort Knox restricted area. Assign westbound flights on 17R a SID based on a westward divergence of at least 15&Mac251; from runway heading, and further plotted to minimize noise exposure of affected populations.

• Eliminate runway preference entirely. For modeling, change frequencies to approximate equal use of both runways. Advise operational steps needed to achieve parity, if any, beyond runway assignment by destination. Manipulate STARs and SIDs to minimize noise exposure of affected populations.

Apply southbound divergence to all departures on 17R, using a SID achieving at least 15&Mac251; west of runway heading, and further plotted to minimize noise exposure of affected populations.

• Reverse runway preference. For modeling, reverse current runway use frequencies. Manipulate STARs and SIDs to minimize noise exposure of affected populations.

Apply no divergence on 17R, except during simultaneous operations. Assign flights on runway 17R a SID based on runway heading, and further plotted to minimize exposure of affected populations. Report implications for avoidance of Fort Knox restricted area. Report incidence of simultaneous operations, and for those cases assign flights on 17R a SID based on a westward divergence of at least 15&Mac251; from runway heading, and further plotted to minimize noise exposure of affected populations.

Measures deferred or dropped

• Many of the measures previously endorsed by the Study Group in the categories of flight tracks, approach and departure procedures are now embedded in the central aim of determining and applying optimal flight tracks. These would therefore no longer need separate treatment:

Uniform turning criteria

Specific angle of divergence

Uniform divergence of all departures

Maximum use of ILS corridors

VFR restrictions

• Selected measures characterized as "voluntary" should be carried forward, but not represented in modeling, since their effects can’t be forecast with confidence:

Delayed flap and gear extensions

Close-in and distant thrust procedures

Reduced-thrust departures

Fleet mix goals

• Measures already applied, and requiring no apparent further action:

High-speed exit taxiways

Prohibit substandard aircraft

Noise compatibility briefings for pilots and controllers

• Measures for which the Study Group accepted consultant recommendations against, or could not achieve consensus to pursue, and which are therefore excluded from the strategies outlined above:

Reverse thrust restrictions

Facility relocation

Capacity limitations

Partial or complete curfews, except as necessary to minimize exceptions to contraflow operations

Noise budget

Operational quotas

Flight training restrictions

Noise-based variable landing fees

• Measures appearing to lie beyond the capacity of model-supported analysis, omitted from strategies outlined here but reserved for further treatment elsewhere in the study:

Show effect of full conformance to current noise compatibility program

Raise tailwind threshold for runway use

The preceding is intended to represent a complete account of the measures put forward by the Study Group in its 10 December 1999 consolidation. Please advise of any apparent lapse, or other suggestions.


				Noise Abatement Strategies Memo
BACK to Meetings Notes				February 14, 2000 MEMORANDUM TO: LFA/Bill Willkie, Project Manager FROM: 150 Study Group/Lt Col Tom Marks, Chair SUBJECT: Noise Abatement Strategies The attached noise abatement strategies are a consolidation of measures approved for analysis by the 150 Study Group at its February 3 meeting, based on suggestions from your October 15 presentation; refinements or additions put forward by the Study Group’s various committees and adopted on December 7; and feedback furnished in your presentation of January 13. The Study Group is guided, as before, by its aims to: • reduce noise contours • leverage technology • make flight patterns more consistent, hence more predictable • reduce exceptions to standard procedures • keep information affecting airport operations accessible to the public • respect operational needs and regulatory imperatives The discussion attached here is an effort to make a complete account and disposition of measures previously adopted, and lay out an experimental design that achieves the most robust coverage for the resources available. But the Study Group fully recognizes the criticality of this phase of the study; so it’s important to emphasize some key aspects of near-term activity that will make or break the effort. These include: • Precise, mutually understood composition of each strategy. To insure fidelity of the design and implications of results, no uncertainties should remain about measures included or excluded; how measures are represented for analysis; or interdependencies arising in the analysis. Rationale must remain clear throughout, and follow-on documentation planned and previewed to preserve the consensus of the group. • Close - intimate - communication on analysis. The Study Group needs a clear view of critical inputs developed for modeling—flight tracks, placement of navigational aids, and the like—to avoid surprises and prompt any necessary course correction. Emerging insights must be relayed right away, and anomalies identified for further review. • Precise definitions of key terms. Some key examples that have already led to woe in discussions and policy reviews to date: "preference/preferential use" "peak/non-peak" "voluntary measure" • Open-ended review of results. Broad discussion of the substance and implications of the analysis are essential to an enriched ‘package’ that directs results to specific local needs. Assumptions and conclusions must be challenged at every turn to confirm their rigor, with ongoing feedback directed to refining and improving them. In short, work in this phase is crucial to study results. "Oops" is consequently no longer an affordable part of the vocabulary. Should any of the Study Group’s noise abatement strategies require elaboration beyond that provided in the attached discussion, please contact me without hesitation. We look forward to your consultation in moving this process forward. February 14, 2000 Noise Compatibility Study Group Noise Abatement Strategies, as Approved The strategies outlined below are for detailed analysis in support of the Louisville Noise Compatibility Study. For purposes of economy, each of the three principal alternatives combines measures oriented on abatement north, and in turn south, of the airport. They are not paired in any self-conscious way; on the contrary, effects of these measures north and south of the airport will have to be disaggregated as clearly as possible to permit meaningful choices for each case. Measures anticipated as net benefits in any scenario become common elements of each strategy. Our understanding is that the marginal contribution of any of these measures can be isolated as required in a post-processing phase of the analysis. In sum, the noise abatement strategies laid out here vary according to runway use. To the north, the strategies vary according to runway preference; to the south, according to runway divergence. Common measures, in turn, aim to reduce noise exposure further through optimal orientation of, and minimal deviation from, flight tracks; application of available operational, physical, regulatory, and management measures; and documentation of emerging technologies and practices that may mature for future consideration. Common elements • Minimize contraflow exceptions. Postulate procedures that would direct scheduled flights during contraflow periods into conforming patterns, by rescheduling; leveraging the interim between arrival and departure periods; proposing additional pauses during these periods; or other means to direct all operations but emergencies to the south during the contraflow period. • Determine and apply noise-optimal prescribed flight tracks (STARs, SIDs) for all six runways (11, 17L, 17R, 29, 35L, 35R). Combine detailed knowledge of practical flight operations and local population distribution to plot routes for arrivals and departures that yield minimum noise exposure to populated areas. Observe currently prescribed minimum runway divergences, except where otherwise indicated below. Incorporate considerations of simultaneous operations; elevation of affected neighborhoods; and restricted airspace around Fort Knox. Provide for minimal exceptions from prescribed tracks, in cases of pilot-declared emergency, weather extremes and the like. • Apply required navigational performance standards (RNP), or hardware specifications, to minimize deviation from prescribed flight tracks. Develop and apply the strictest standard that can reasonably be imposed on users of the airport with available technology to insure fidelity to prescribed routes. • Operational measures (potential excursions). Apply such constraints as are necessary to insure that prescribed flight tracks are used consistently in non-emergency situations, and to the best effect. Visual approach clearances, for example, should not permit deviation from prescribed tracks, but only add flexibility to factors like delayed flap and gear extension that would further reduce noise exposure. Thrust procedures, if practicable, should be applied uniformly, to avoid complicating the tasks of pilots using the airport. Of the remaining measures proposed in these categories, detailed analysis should include Higher holding and maneuver altitudes, in particular as required to compensate for increased elevation of selected areas Steeper glide slopes and two-stage approach procedures, as required to compensate for increased elevation of selected areas Use prospective runway extension for takeoffs (2005 case) • Facilities, use restrictions, and regulatory measures. Specific measures endorsed by the Study Group include Postulate placement and use of whatever navigational aids are necessary to support arrival and departure tracks (STARs, SIDs) developed above Assign displaced arrival thresholds where runway length exceeds that required for safe operations, including prospective runway extension Require conformance with noise compatibility program by all aircraft unless specifically excepted (advise recommended exceptions) Define and apply feasible limits based on event metrics (e.g., so many operations permitted to exceed an SEL of X dB in a given period) (advise specific recommendations) Continue, and propose means to expand, restrictions on engine run-ups • Management measures. Establish airport noise office Form community noise forum Maintain and expand study Web site and public information centers Conduct selective ongoing noise monitoring Collect and analyze ongoing flight track data Conduct periodic in-house modeling to estimate current noise exposure • Document knowledge of ‘emerging’ measures. Education of all affected constituencies, and a robust implementation program poised to take advantage of new developments, are central goals of the study effort. It’s therefore important that study reporting include all available information on any measures deferred in the present program because of practical or technological developments that are not yet mature. This knowledge base will permit orderly revisitation and further consideration of these measures as their maturation warrants. Specific measures endorsed by the Study Group that preliminary assessment places in this category include: Advanced navigation aids (laser homing, microwave landing systems, military-specification GPS equipment, "ADS-B") Counter-frequency generators On-site exterior sound absorption media Next-stage engine technology Principal alternatives • Limit east runway preference to daytime only. For modeling, retain current runway use frequencies during the day (7AM–10PM), but change nighttime frequencies to approximate equal use of both runways. Make initial array based on destination; advise if further steps necessary to achieve parity. Manipulate STARs and SIDs to minimize noise exposure of affected populations. Apply southbound divergence according to destination (as currently). Assign eastbound flights on runway 17R a SID based on runway heading, and further plotted to minimize exposure of affected populations. Report implications for avoidance of Fort Knox restricted area. Assign westbound flights on 17R a SID based on a westward divergence of at least 15&Mac251; from runway heading, and further plotted to minimize noise exposure of affected populations. • Eliminate runway preference entirely. For modeling, change frequencies to approximate equal use of both runways. Advise operational steps needed to achieve parity, if any, beyond runway assignment by destination. Manipulate STARs and SIDs to minimize noise exposure of affected populations. Apply southbound divergence to all departures on 17R, using a SID achieving at least 15&Mac251; west of runway heading, and further plotted to minimize noise exposure of affected populations. • Reverse runway preference. For modeling, reverse current runway use frequencies. Manipulate STARs and SIDs to minimize noise exposure of affected populations. Apply no divergence on 17R, except during simultaneous operations. Assign flights on runway 17R a SID based on runway heading, and further plotted to minimize exposure of affected populations. Report implications for avoidance of Fort Knox restricted area. Report incidence of simultaneous operations, and for those cases assign flights on 17R a SID based on a westward divergence of at least 15&Mac251; from runway heading, and further plotted to minimize noise exposure of affected populations. Measures deferred or dropped • Many of the measures previously endorsed by the Study Group in the categories of flight tracks, approach and departure procedures are now embedded in the central aim of determining and applying optimal flight tracks. These would therefore no longer need separate treatment: Uniform turning criteria Specific angle of divergence Uniform divergence of all departures Maximum use of ILS corridors VFR restrictions • Selected measures characterized as "voluntary" should be carried forward, but not represented in modeling, since their effects can’t be forecast with confidence: Delayed flap and gear extensions Close-in and distant thrust procedures Reduced-thrust departures Fleet mix goals • Measures already applied, and requiring no apparent further action: High-speed exit taxiways Prohibit substandard aircraft Noise compatibility briefings for pilots and controllers • Measures for which the Study Group accepted consultant recommendations against, or could not achieve consensus to pursue, and which are therefore excluded from the strategies outlined above: Reverse thrust restrictions Facility relocation Capacity limitations Partial or complete curfews, except as necessary to minimize exceptions to contraflow operations Noise budget Operational quotas Flight training restrictions Noise-based variable landing fees • Measures appearing to lie beyond the capacity of model-supported analysis, omitted from strategies outlined here but reserved for further treatment elsewhere in the study: Show effect of full conformance to current noise compatibility program Raise tailwind threshold for runway use The preceding is intended to represent a complete account of the measures put forward by the Study Group in its 10 December 1999 consolidation. Please advise of any apparent lapse, or other suggestions.
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