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.
Meeting Notes
July 31, 2001
Attendees: Bob Adelberg, Robert Barker, Terry Borne, Dorn Crawford, Teresa Cusick, Emily Evans, Mary Rose Evans, Greg Gapsis, George Hudson, Tony Copeland-Parker, John Sistarenik, Bob Slattery, and Dannie Weber.
The committee meeting was called to order at 7:00 PM. Its purpose was to preview noise contour maps to be presented in Study Group Meeting #5; make comparisons with preliminary model runs conducted last fall; and discuss proposed model excursions. The committee was also introduced to the RAA Noise Officer, Bob Slattery, who made a presentation on his activities, and flight track monitoring equipment under evaluation.
The committee first approved notes of its previous meetings, then heard from Bob Slattery, whose new staff position was the first concrete result of the Study Group’s work. Bob discussed his assumption of handling noise complaints (formerly done by airport public relations), and gave switchboard (368-6524, x112) and direct (375-4546) phone numbers to contact him.
He then distributed a handout describing PASSUR, a commercial flight track monitoring system the airport is testing. To illustrate its capabilities, he continued with a presentation on nighttime contraflow operations recorded during the week of July 16-20, including patterns of arrivals and departures, flight tracks in the airport vicinity, and specific listed flights operating as exceptions to contraflow.
He described the PASSUR system as a hardware and software combination for collecting radar signals, and then managing the resulting data. He said the airport is also evaluating enhanced software packages that would more powerfully manipulate the data, and provide various display and analysis capabilities. He agreed to return to the committee with further details as he compiles them.
The committee then turned to an examination of the noise contours resulting from recent consultant model runs, and scheduled for presentation at Study Group Meeting #5. After reviewing main elements of the three noise abatement strategies modeled, members examined
• preliminary noise contour maps for each alternative, and a map depicting the 2005 base case
• new contour maps for each alternative, overlaid for comparison with the 2005 base case contours
• a chair’s discussion paper laying out key considerations, including
• chronology
• measures varied between the alternatives
• refinements anticipated for the final model runs
• an illustrative review of the several runs of Alternative 3, and implications
The review compared contour lobes for the east and west runways that, in different runs, had exceptions to contraflow either preferred or not preferred; then graphically combined the two non-preferred lobes. This was to get an idea what a contour might look like with these operations reduced overall. The graphics also estimated a corrected offset path for the west runway.
The paper then compared this estimate with the latest actual model run for this alternative, intended to correct the offset and reduce contraflow exceptions by half. The modeled contour follows about the same offset path as the estimate, but the northern lobes both remain much larger – in the northeast, even larger than in the preliminary run. The committee resolved to take up this anomaly with the consultants.
The committee moved on to a direct review of all three new contour maps, in comparison to the preliminary runs. The other two alternatives, 1 and 2, did show improvement over the preliminary results that looked like reasonable effects of the reduced exceptions to contraflow. Members then examined results south of the airport, where varying divergence procedures were tried. With larger contours, this also seemed the best place to look for effects of improved fidelity to flight tracks. Consultants had been provided refined figures from a separate analysis for how much dispersion should be modeled for the forecast fleet, depending on available navigation equipment. The entire UPS fleet, for example, was upgraded from within ±10,000 feet to within ±45 feet of the prescribed flight track.
But the contour lobes south of the airport appeared virtually unchanged from the preliminary runs. This reinforced the observation that the divergence options didn’t have much effect. Apparently the south contours are dominated by contraflow operations, which occur in heavy enough volume that most departures are simultaneous, so divergence would be mandatory.
More troubling was the nil effect of the improved dispersion parameters. Compared to the base case, all the alternatives had considerably longer and narrower south lobes in the preliminary runs, just from extending the flight tracks’ turning points further away from the airport. But fidelity to the tracks, improved as much as 500 times, had no further effect. The committee resolved to seek potential explanations for this result.
The chair undertook a brief discussion of model excursions consultants had proposed on flight tracks, divergence options and contraflow exceptions, comparing those with modeling questions brought into focus by the new runs: an imbalance in the volume of traffic north and south of the airport; examining the anomalies noted; and assessing untested measures like a displaced arrival threshold. A final case set is to be presented at the Study Group meeting August 23.
The chair also summarized the revised study timeline proposed by the consultants, which would complete at least the public portion of the program by the end of the year. He pointed out that this still leaves final report drafting, RAA approval, publication and forwarding to FAA for final action into next year. FAA regulations allow the agency six months to review proposed programs, and an indefinite period to act on "operational" measures that would change flight procedures at the airport. The Study Group, or its successor, will of course follow this process actively.
Between now and then, members recalled many measures adopted in the Study Group’s common program that remain to be treated beyond the modeling effort. These include such steps as formulating and prescribing standard approaches and departures (STARs and SIDs). Existing procedures provide ample room for refining approach and departure paths, waypoints and maneuvering altitudes, within existing FAA guidelines. Such measures could greatly relieve noise impacts beyond the Federal threshold contours, especially in elevated areas, and in areas that might otherwise have increased overflights. The committee anticipates focusing close attention on these measures once the modeling is done.
The committee agreed to keep in close contact after the new results are presented to the Study Group, to share impressions and develop inputs for the preferred alternative to be decided at Meeting #5A. A committee meeting will be scheduled shortly before that to consolidate its report. The meeting adjourned at 9:20 PM.