• Committee discussion paper of Jan 21 on screening noise abatement measures

• Extracts of Jan 13 consultant presentation on abatement measures, screening results, noise abatement strategies, and suggested noise mitigation measures and screening criteria

• Enlarged maps of current and projected noise exposure in the study area

• Reminder notice of Feb 3 Study Group meeting

Advanced Navigation Technology
The Study Group adopted measures aimed at assessing ground-based aids (markers, beacons, lasers, etc), and in turn airborne aids (GPS/FMS [current versus military-specification], MLS, etc). The consultants’ response was to offer investigation of fully mature technologies such as distance-measuring equipment and markers, and development of FMS/GPS procedures. Committee members noted that GPS procedures have already been developed and published for all active runways except 11, and that these would not in any case be helpful in judging the distribution of currently available equipment, nor the prospects for more accurate control if available military equipment is declassified. Members reiterated more broadly their interest in documentation of other emerging technologies and systems that may deserve monitoring and later reconsideration.

Airport Facilities
Several of the measures listed in this category could arguably qualify either as abatement or as mitigation measures – e.g. ‘hush houses’, counter-frequency generators, or sound absorption media. The committee accepted consultant recommendations to defer these to the mitigation assessment, with the stipulation that the assessment would in any case include state-of-the-art documentation for any measure not yet mature.

The principal measure recommended in this category would analyze the effect of displaced thresholds for arrivals on the longer west runway. The committee endorsed this recommendation, without prejudice to the complementary measure formulated under "Departure Procedures", that would in effect displace the threshold for departures as well, by taking advantage of any prospective runway extension or overrun rated for the purpose.

High-speed taxiways were dropped from further analysis, since they are already available; conversely, facility relocation was dropped for lack of practical concrete alternatives.

Airport Use Restrictions
Most measures that would have the effect of restricting users’ access to the airport were recommended against for their potential interference with interstate commerce. The committee proposed only to carry forward some modest prospects in areas like the use of event metrics to limit noise emissions that exceed some cumulative threshold over time, and potential restrictions on out-of-cycle arrivals and departures in conjunction with minimizing exceptions to contraflow operations. The remainder, members agreed, simply wouldn’t attract consensus in the Study Group.

Airport Regulations
Committee members agreed that measures proposed in this category were due little additional treatment, since they either (1) are already in place (noise compatibility briefings, run-up restrictions), (2) have little applicability to our case (flight training restrictions), or (3) were already addressed under other categories (landing fees).

Management Measures
Most of the measures in this category have to do with effective implementation and monitoring, rather than central formulation and analysis, of the noise compatibility program. The committee therefore found it easy to endorse recommendations favoring these measures, particularly those, like establishing an airport noise office and community noise forum, already adopted by the Study Group. Several other measures simply enlarged on the capabilities such bodies would incorporate.

Some disappointment was expressed in the evident inability of the consulting team to model the effect of full conformance with the current noise compatibility program. This measure was formulated to evaluate the implementation task, by comparing the actual current base case to a fully compliant one. The problem the proposed measure exposed was of clearly understanding, and accurately representing, the measures presumed to comprise the current program. Without this kind of clarity, modeling isn’t possible – but then neither is faithful implementation. While still inexecutable, therefore, this proposal served at least to underscore the need for precision in terms and in documentation of the new program. There can simply be no doubt of its particulars, and no difficulty in its interpretation and/or replication.

Strategies
The committee agreed that noise abatement strategies for detailed analysis need to be constructed with extreme care, and the analysis itself closely monitored in progress. Measures common to all strategies are as important to those distinguishing them, and rationale and documentation for each must be precise and complete. Emerging results, and any anomalies, must be conveyed to the Study Group and the appropriate committees in real time, for open-ended review and course correction when appropriate.

In proposing specific strategies to the Study Group, committee members wanted to avoid ill-defined or imprecise measures, but at the same time be sure nothing would be excluded prematurely or without clear justification. In the former case, measures like "daytime contraflow" and "I-65 corridor" had not achieved clarity, nor attracted support. In the latter, a number of operational measures and technology options were discounted in the screening process, as noted earlier, for reasons that were unclear or unpersuasive.

The committee ultimately determined that

• Common measures should concentrate on minimizing deviations from standard procedures, including contraflow, standard approach and departure routes, and required navigational performance

• Further common elements should be added that enhance fidelity and facilitate implementation and oversight.

• Measures that look promising, but for which technology or policy is not yet mature, should be fully documented for further study and monitoring.

• The original design of the analysis, showing the effects of key alternative runway preferences north of the airport, should be retained.

• Measures should be added to evaluate varying uses of runway divergence south of the airport, providing that alternatives take full account of the Fort Know restricted area.

• Results need to be disaggregated for each major lobe of the resulting noise contours, so effects can be fully and distinctly evaluated north and south, east and west.

Members arrived at a format for the committee’s presentation to the Study Group that would lay out the critical questions to be addressed in this phase of the study; express caution about precision of concepts, terminology and rationale; prescribe key elements of the process; and describe clearly the common and alternative measures comprising the major strategies recommended for analysis.

The committee concluded with a brief discussion of noise mitigation measures and screening criteria. While these measures were certainly of interest to individual members, they agreed their thrust – land use measures, or things done on the ground to remediate, compensate or prevent noise exposure – lay outside the specific focus of the Navigation Committee. Members committed themselves to providing input on these measures through the appropriate other committees.

The meeting adjourned at 9:45 PM, with the timing of the next meeting deferred pending the results of the February 3 Study Group meeting, and determination of necessary follow-up action.

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