South Metro Airport Action Council
** S M A A C **


by James R. Spensley, President
November 15, 2004

On behalf of our Board and Membership. It is troubling that the Commission will vote to submit the Part 150 Noise Compatibility Program (NCP) Update in this form, at this time, having by other actions and pending actions invalidated the premises on which it is based.

The contour map was drawn for thousands fewer 2007 operations than are said to be needed and used to justify further-expansion plans now before the Commission (and likely to be adopted in some form). It is unclear in the Update if the NCP will be continued after 2007, and the Commission has not corrected past noise exposure maps – as common understandings of the FAR Part 150 require. It is NOT, as the Commission and staff have so often claimed, based on the Commission’s reasonable and best projections. It is NOT based on the facts in evidence, but was, as a matter of fact, developed months before review or comment by the public or even the Noise Oversight Committee. As we said at the September 7th session, the Update is not worthy of the Certification on Page 2.

Operations were increased over 2002 by 14.3 % for January 2003 to September 2004 (8% per year), but the for-2007 contour maps are based on 3% per year growth. These numbers were not reconciled with Metropolitan or State economic growth (need) projections. It is unknown if the numbers comport with previously projected economic growth needs, because the hubbing factor trend is unreported; and, because the percent Minnesotans, and economically significant to Minnesota visitors, are not well accounted for in the formulae anyway.

SMAAC challenged the passenger use projections and the derivation of operations projections throughout the process, but comments did not reach you until after you had voted to accept your consultant's limited-by-contract projections. We noted that significant differences in noise exposure can be computed from the same number of annual operations depending on peak rates and runway use, and we said the for-2007 map is based on an extremely unlikely case.

I met with HNTB to discuss how the contours were drawn (case details such as peak-rate and runway use, number of flight tracks). HNTB confirmed that:
1. 140 operations per hour using 3 active runways accounted for 90% of all modeled operations.
2. The number of tracks resulting from runway operations was determined from 10 days of runway data collected in 2002, which necessarily limits the accuracy of (creates errors in) "weighting" flight noise per track in the model. Note: Weighting normalizes off-track noise using 2002 data (patterns of use). Because use of 17-35 was made up, new flight tracks for existing-in-2002 runways are introduced. No Commissioner participated directly in developing the flight tracks and no questions were asked about this aspect or the resulting runway use plan when HNTB presented to NOC, to P&E, or to the Commission.

Our engineering analysis is that the INM averages event noise. If the INM were run with the only difference being the number of flights, and at least 100 operations were assigned to each flight track, there would be no difference in the plotted contours. Contours would be smaller for 1,000 CRJ flights than for 100 DC-9 flights.
The 1996 Legislature was wary that the SIP might be limited in spite of considerably more operations. They intended, as a condition of MSP expansion, a full 5 db insulation program out to then-projected for-2005 60 DNL (or actual 2004 runway use if that was the worst case under the parallels). The two-year 17-35 delay arguably converts 2005 to 2007. In 1996, MAC committed that these neighborhoods would be treated limited only by available contractors and the SIP implementation and contracting processes.

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