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.
October 2, 2001
Attendees: Bob Adelberg, Robert Barker, Terry Borne, Dorn Crawford, Teresa Cusick, Mary Rose Evans, Ron Haga, George Hudson, Tony Copeland-Parker, John Sistarenik, Bob Slattery, Mike Zanone
The committee was called to order at 6:05 PM. The purpose of its meeting was to conduct a second review of noise contour maps presented in Study Group Meeting #5; consider concerns raised by consultants about proposed operational measures; and begin formulating its abatement strategy recommendations for Study Group Meeting #5A.
The committee first approved notes of its last meeting, then studied questions put to consultants by the Study Group chair based on its and other committees’ inputs. Their object was both to resolve questions raised about the Meeting #5 presentation, and to clarify issues the consulting team had raised about key elements of the Study Group’s proposed abatement measures. The Study Group chair had forwarded the following questions, and received the responses indicated:
Q: Please explain why there is no visible change in the Alternative 3 contours between the corrected preliminary run and the latest corrected run, with 50% contraflow exceptions removed. The difference is clear in Alternatives 1 and 2.
A: Consultants had not applied the change in runway preference between the alternatives to these specific operations, which occur during contraflow periods. A subsequent run with these changes applied produced consistent results.
Q: Has LFA changed its mind about the importance of weather minima, so that it makes a difference in the contours? If so, why? Why didn't LFA use the parameters specified last fall, if it makes a difference now?
A: This question arose from consultant concerns about availability of a proposed non-precision approach in bad weather, which attracted citations of previous Study Group correspondence laying out specific weather parameters for the approach. After affirming that the minima derived from local simulations would make the offset approach available more than 90% of the time, the question was judged moot.
Q: How often will aircraft be able to use the offset approach? What percent of the time will the weather minima be met?
A: This question was answered in the course of resolving the preceding one.
Q: The offset flight path, including release point, was specified last fall. Didn't LFA assume, as the study group did, that arrivals 'breaking left' and those 'breaking right' to reach the centerline would roughly balance out? If so, why change now?
A: After some discussion, there seemed to be general agreement that deviation from the approach path should be about the same to either side, as the question suggests.
Q: Please explain the grid maps you presented at Meeting #5, highlighting changes in contours below 60 DNL, considering FICON guidelines.
A: This question addresses lingering uncertainties about (1) whether Federal guidelines address noise impacts below 60 DNL; (2) whether available simulations give accurate results below 60 DNL; and (3) whether sources other than aircraft tend to dominate ambient urban noise levels below 60 DNL. Consultants could only affirm that the model produces accurate results based on the data and parameters available to it.
Q: Will the study group still be getting grid maps oriented on single-event metrics from LFA?
A: Yes. Consultants promised to produce grid maps of peak noise levels in the study area, as required by an overlooked study task.
Q: When viewing the noise impact data south of Louisville International Airport, does this data include both Bullitt and Jefferson Counties or only Jefferson County before the county line?
A: Data are compiled and presented for the whole study area, regardless of political boundaries.
With these responses in hand, the committee again reviewed the main results of the Meeting #5 presentation, with subsequent refinements. It’s clear that a reversal of the airport’s current runway preference, with an offset approach to runway 17R and the other operational measures adopted by the Study Group, produces by far the best results north of the airport, in terms of reducing the number of people exposed to noise above 65, and even 60, DNL.
In the south, the dominance of peak operations that demand both runways and divergent departures, especially during contraflow, frankly prevents the Study Group’s alternative measures from having much effect. Significant relief is provided there, however, by measures common to all alternatives, like extended turning points, tighter flight tracks, and higher maneuvering altitudes, all expected components of standardized arrival and departure procedures to be implemented with an approved Louisville program.
Concerns persist about the effects of these alternatives beyond the noise contours, especially in elevated areas, and those likely to have increased overflights. These concerns are sharpened by the continued need for development of proposed measures not directly represented in the model, or implicitly assumed by it: standardized flight paths and procedures, strict adherence to glide slopes, restriction of visual approaches, etc.
The chair undertook to prepare a draft presentation of the committee’s recommendations and concerns for use at Meeting #5A, now scheduled for October 18th. The committee will meet again shortly before that to review the draft ands make final refinements. The meeting adjourned at 9:10 PM.