Missing: Mike Byrnes, Paul Brown.

Location. Aurora City Hall
Meeting called to order by Nick Kaiser at 7:05pm.

HMMH arriving Thursday, November 1, 2001 to install the noise monitors for the next (and final) monitoring session.  The 6 installations include Rwy 17, Rwy 35, Charbonneau, Deer Creek, Jake's house (Main Street), Nick's house (Off Airport Road).

Nick asked of there are any questions from the HMMH report.  There was a discussion about the flight paths.  Daren passed out an enlarged flight path map but it was difficult to decipher without clarification from HMMH.

The committee concluded that the HMMH report shows only preliminary information and it is hard to draw any conclusions from it without getting more complete and refined data when HMMH completes the study.  The model is supposed to be complete by the end of November or early December.

At 7:30 Daren placed the conference call to HMMH, Gene and Steve.

Memo of October 10th was discussed with the following questions and answers.

1. What is LMAX?
---It  is the maximum measured decibel level recorded by the microphone for an event.

2. What is SEL?
---The amount of time that the single event lasted.   Stands for Sound Exposure Level.

For example, over station # 4 (Nick's house) a single event jet noise level was 46 with an SEL of 60.  At this station, single event piston levels (LMAX) ranged between 44 - 73 with an SEL of 57- 82.  In the model, a lower decibel reading that lasts for a longer time can produce more negative noise impact that a louder, shorter duration noise event.

A discussion about various noise recordings in the HMMH report from noise monitoring session #1 were discussed.   Both intensity of noise as well as duration are used in the model to produce the noise contours. They normalize to one-second periods on a bar chart.

3. A question was asked, how many events make up the tables?  For example at site #1 southwest of the airport, 140 departures were counted but at site #4 (Nick's) there were 193 events.  Reason was that a takeoff, base leg and downwind leg in the traffic pattern may be recorded as two to three distinct noise events.  So, monitors # 4 and # 5 may show more events than there are airport operations.

4. Flight track map.  HMMH will add neighborhoods on the next map so we can relate the flight path to the populated areas below the aircraft.  An aerial photograph will be used and the results will be overlaid.

5. During monitoring phase # 1, Runway 17 (to the south) was in use for  83% of the operations and runway 35 (to the north) was in use 17% of the time.

6. Survey results from phase # 2 will be input into the model in late November and the model will be run by early December.  We requested that the results be completed by the November 28th meeting so we can get on with mitigation proposals. 

7. Three contours will be computed: a) Year 2001, b)  5 years out, c) Future projection

8. The committee said they had discussed 5 or 6 mitigation measures and wanted to see the results of each.  HMMH said that they had only 50 hours in the budget for mitigation study, that the main focus of the contract was to develop the noise model.  Mitigation measures that the committee has discussed were mentioned, including right Traffic 17, Calm wind runway 35, eliminate touch and goes on 17, climb to 1200 before turning, reduce power.

9. Bob Bahr and Eli Elizaga will be in Aurora to set up the noise monitoring equipment.  They will record take observations Friday, Sat and Sunday, Nov 2,3,4. (Jennifer, previous monitoring person is no longer with HMMH).  The equipment will continue to record until the morning of November 9th.  Daren will check on the equipment daily and will pick it up on 11/9/01 up for return to HMMH.

10.  Daren said by the end of December the mitigation measures can be plugged in to show results.  At the Decibel December 19, 2001 meeting, the committee will document the mitigation measures which they will propose to be modeled HMMH.

11. Daren asked if Decibel members can observe and make inputs during the second monitoring phase, HMMH said it is not required but that any input would be appreciated.

12. Jack Kahle was concerned that the budget did not include adequate mitigation measure modeling and that more money would have to be spent to arrive at satisfactory results.  HMMH said that they could look at several mitigation measures in the model collectively, but probably not individually within the present scope of the project.

Next meeting.  Aurora City Hall
Wednesday, November 28, 2001 7:00AM to 9:00PM

Meeting was adjourned at 8:40pm

Email any corrections to jake@infoviva.com