Meeting Notes : Navigation Committee
Committee notes reflect the views and opinions of the committee members and not necessarily those of the Noise Compatibility Study Group, Coordinating Council, Regional Airport Authority of Louisville and Jefferson County, or the Consultant Team.
Attendees: Dorn Crawford, Mike Clancey, Teresa Cusick, Mary Rose Evans, Ron Haga, George Hudson, Aaron Lucas, Bob Slattery
The committee meeting was called to order at 7:10 PM. Having heard consultants’ presentation of noise contour maps in Study Group Meeting #5, members aimed to review the effects of the main noise abatement alternatives and model excursions, study impact statistics, and evaluate remaining questions. The original goal of the meeting, to develop final committee recommendations for a Louisville noise abatement strategy, was deferred, along with the full Study Group meeting scheduled for September 20 for the same purpose. New analytical concerns raised by the consultants could not be promptly addressed by the airport staff in the wake of the September 11 terrorist attacks and their impact on airport operations, so the Study Group meeting was rescheduled for October 18.
The committee approved notes of its July 30 meeting, then began by reviewing a graphic showing the disparity between the noise exposure map approved under the previous noise study for 1997 with the actual exposure for 1998, as assessed by the current study. This graphic, whose noise contours appeared originally at Study Group Meeting #3, serves a number of key purposes in guiding current and future study efforts. In particular, it underscores the importance of:
• documenting noise abatement measures carefully, so that what’s modeled is what’s actually implemented
• maintaining a healthy skepticism about the power of ‘professional judgment’ to forecast future airport noise exposure
• monitoring and overseeing implementation, and providing authoritative feedback to operators on performance against program standards
The committee then turned to a review of the noise contours presented at Study Group Meeting #5. The discussion was guided by a series of ‘food-for-thought’ papers circulated before the meeting. The first paper, a discussion of the contour maps, compares refinements expected in the final runs with results actually observed. The paper then summarizes what the runs seem to be showing about the effects of alternative measures north and south of the airport. It then discusses additional runs presented by the consultants that attempt to isolate the effects of some of the core individual measures proposed. Finally, it reprises key questions still unaddressed in the modeling effort.
The second paper is a discussion of noise impacts under the three abatement alternatives, compared to the base case. This paper includes a table adapted from the impact data presented by the consultants, showing the numbers of people, houses, sensitive facilities, and historic properties and districts remaining within the DNL 60, 65, and 70 contours in each case. These figures show some remarkable potential for achieving reductions of up to three-quarters of population exposed over DNL 65, with similar benefits in the other categories noted.
Despite these potential gains, committee members remain concerned about collateral effects of air traffic along flight tracks extended beyond the range of the noise contours. Preserving consensus for choices among the three alternatives, north and south, will clearly depend on firm commitments to complete development of other measures that address these issues, e.g:
• plotting extended recommended flight tracks to guide air traffic for minimal impact throughout the Louisville airspace
• proposing navigational fixes to canalize traffic into predictable corridors
• marking up, and/or redrafting, approach and departure procedures to enhance noise abatement
• collecting and studying additional demographic data on areas below noise contours that still experience significant changes in overflights
The third paper is a discussion of grid/point maps representing preliminary work on the last point above. Committee members briefly acknowledged the need for additional work, as outlined in the paper, to:
• acquire specific demographics for affected areas
• balance portrayal of increases and decreases in overflights
• portray the comparable impact of current deviations from approved noise exposure
• measure ambient noise levels to establish a baseline for evaluation
Finally, the committee needed to take account of uncertainties raised by the consultants about the model runs on the abatement alternatives. These included questions about
• weather minima that should apply to the offset approach
• specific maneuvers aircraft are assumed to use to acquire the runway centerline
• whether carriers would agree in advance to use the proposed approach
• and if not, whether compensating departure traffic could be added to the west runway, even when it’s already preferred, to make up the shortfall in runway use
While noting that these appeared to be questions to resolve in the initial formulation of such a measure, rather than after record model runs, committee members agreed that they needed closure before proceeding to a final recommendation on the preferred abatement alternative. The chair therefore proposed to call another meeting once the situation could be clarified and appropriate options developed. The meeting adjourned at 9:10 PM.