The controversy over new overflight paths is a distraction, and noise and pollution impacts are unknown. State, Metro, and city offcials should be looking for safe, sufficient, and affordable air service, without more noise and pollution.
In spite of a decrease in daily flights and passenger capacity (down steeply 2005-2007, and still below 2004 levels), there are more flights at peak hours at MSP than ever before.
Two years ago (September 16, 2010) two planes taking off at the same time from MSP nearly collided over Highways 77 and 62. As a result, FAA and airlines made a series of changes in departures and runway use. This resulted in more overflights north of MSP and thousands of complaints.
To avoid reducing runway use per hour (high rates support the Delta-Sky Team hub), FAA and airlines are flying at near minimum safe separations as a consequence of national FAA policy. FAA airport towers are directed to allow approaches and departures guided by "performance-based navigation (PBN)."
The South Metro Airport Action Council notes that noise exposure would be lessened if operations per hour were limited, but more importantly, it would be safer and less costly. MAC only postponed its approval of the PBN routes, but FAA claims it has the need and authority to implement the "RNAV/PBN" routes.
Limited flight paths will increase noise intensity both along and across the repeated tracks, especially as average attained altitude will be lower near the airport. Sound intensity "spreads out" on both sides of a route in proportion to the height, and noise from adjacent tracks will overlap at a distance from the runways. The incomplete and misleading idea that changing to PBN routes will reduce airplane noise for some at the expense of others was introduced by MAC staff. Noise impacts were inappropriately analyzed by modeling using incomplete parameters, old data, questionable statistics, and airline projections.