More on Slots
RE:Slots are flexible & CAIR response.
In 1999-2001 the Sypher-Mueller report gave several "options" for the future of the airport.
When numbers for commercial flights were higher, there was usually a corresponding drop in "other" activities to compensate and keep the overall activity within the NEF contour.
I too was mystified that in this latest iteration, at a MAXIMUM of 212 slots, there was NOT a reduction in either flight training or helicopter activity.
As Kyle pointed out, and in my opinion, the approach angle would (should?) have an impact on the slots since it impacts the noise footprint. If an aircraft climbs out more quickly and approaches at a steeper angle, the noise "theoretically" stays closer to the airport. I haven't read anything about Porter adopting any revised procedures but I do know that the Q400 is capable and certified to fly these profiles.
I still believe that the airport is operating within the Tripartite Agreement mandate of "limited" commercial flights as there are limits on airport hours and NEF contours & slots - it is far from a free for all.
After looking over the FAA decibel ratings for all aircraft (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/aeab4e3e783d2b6086256e3700762a57/$FILE/AC36-3H.pdf )
I found that the Q400 is indeed quieter than the older Dash 8s that Air Ontario / JAZZ used at the airport.
On takeoff - the Dash 8-100 was rated at 65.7 db, the Dash 8-300 was 65.4 db, and the Q400 was 61.0 db. This would be a contributing factor the to higher proposed slot totals. The smallest Dash 8 is also the loudest (and least efficient) Dash 8.
On Approach to land, the Dash 8-100 was 81.2 db, the Dash 8-300 was 80.7 db, and the Q400 was 81.6. Specific flap settings were used to come up with the numbers. To illustrate the variation that flap settings can cause - Q400 on approach with 15 degrees of flap = 83.4 db compared to 35 degrees of flap = 81.6 db.
The FAA document is VERY long and I may have overlooked other settings with even lower decibels for each aircraft since I was getting bug eyed reading it.
Overall, although the Q400 appears to be .9 db louder on approach, it is also up to 4.7 db quieter on takeoff which equates to an overall reduction of 3.8 db when combined. This noise reduction in conjunction with a potential change in takeoff and approach "profiles" (i.e. steep climb and approach) might be enough to explain the proposed slot increase.
The fact that slot numbers have changed several times over the years needs to be viewed in consideration of "HOW" those numbers were obtained and "WHAT" aircraft were being used in the calculations. The combinations (see Sypher-Mueller) are as endless as the differing slot numbers we have seen. The Q400 is relatively new and was not likely part of older calculations. It is illogical that the TPA won't make these calculations public so that we can all understand and verify the process.
Take Care!
Joe
In 1999-2001 the Sypher-Mueller report gave several "options" for the future of the airport.
When numbers for commercial flights were higher, there was usually a corresponding drop in "other" activities to compensate and keep the overall activity within the NEF contour.
I too was mystified that in this latest iteration, at a MAXIMUM of 212 slots, there was NOT a reduction in either flight training or helicopter activity.
As Kyle pointed out, and in my opinion, the approach angle would (should?) have an impact on the slots since it impacts the noise footprint. If an aircraft climbs out more quickly and approaches at a steeper angle, the noise "theoretically" stays closer to the airport. I haven't read anything about Porter adopting any revised procedures but I do know that the Q400 is capable and certified to fly these profiles.
I still believe that the airport is operating within the Tripartite Agreement mandate of "limited" commercial flights as there are limits on airport hours and NEF contours & slots - it is far from a free for all.
After looking over the FAA decibel ratings for all aircraft (http://www.airweb.faa.gov/
I found that the Q400 is indeed quieter than the older Dash 8s that Air Ontario / JAZZ used at the airport.
On takeoff - the Dash 8-100 was rated at 65.7 db, the Dash 8-300 was 65.4 db, and the Q400 was 61.0 db. This would be a contributing factor the to higher proposed slot totals. The smallest Dash 8 is also the loudest (and least efficient) Dash 8.
On Approach to land, the Dash 8-100 was 81.2 db, the Dash 8-300 was 80.7 db, and the Q400 was 81.6. Specific flap settings were used to come up with the numbers. To illustrate the variation that flap settings can cause - Q400 on approach with 15 degrees of flap = 83.4 db compared to 35 degrees of flap = 81.6 db.
The FAA document is VERY long and I may have overlooked other settings with even lower decibels for each aircraft since I was getting bug eyed reading it.
Overall, although the Q400 appears to be .9 db louder on approach, it is also up to 4.7 db quieter on takeoff which equates to an overall reduction of 3.8 db when combined. This noise reduction in conjunction with a potential change in takeoff and approach "profiles" (i.e. steep climb and approach) might be enough to explain the proposed slot increase.
The fact that slot numbers have changed several times over the years needs to be viewed in consideration of "HOW" those numbers were obtained and "WHAT" aircraft were being used in the calculations. The combinations (see Sypher-Mueller) are as endless as the differing slot numbers we have seen. The Q400 is relatively new and was not likely part of older calculations. It is illogical that the TPA won't make these calculations public so that we can all understand and verify the process.
Take Care!
Joe
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