Replacement Terminal Environmental Assessment
12. Can Mercer County and Trenton Mercer Airport request modified flight procedures?
Requests for noise abatement procedures can be voluntary. The four areas covered include preferential approaches and departures flight schedules, rotational use of the runways, flight operational procedures to reduce ground noise, and higher departure angles. The request for modifications to flight procedures as well as noise abatement procedures can be made by the public or an airport and the request would be outside any Part 150 Noise Study or the Terminal EA process. Any requests made do not presuppose an outcome and any changes in procedures may have a detrimental or beneficial impact to one community or another surrounding the airport.
The scheduled commercial airlines at Trenton Mercer Airport make up a small percentage of the overall jet aircraft. The schedule for commercial aircraft flights is based upon aircraft fleet, destinations and possible connecting flights, and economics of the airline serving Trenton and the destinations. The higher percentage of jet traffic is unscheduled or irregularly scheduled based on need by the larger private operators at the airport. Changes to the flight schedules can only be changed for a small number of operations.
The use of runways is entirely based upon the direction of predominant wind and the size of aircraft using the runway. Predominant winds are Southeast to Northeast. Runway 6-24 is 6,000 feet in length and Runway 16-34 is 4,800 feet in length. Runway 6-24 is aligned in the direction of predominant winds. Due to the length of the runways, most commercial and other jet aircraft using the airport will utilize departures from the RW 24 End (Northeast) to the RW 6 End (Southwest) to take off into the wind. Approaches to the airport are critical and more dependent on weather/wind conditions. The approach to Runway 6 has a precision approach that is utilized during poor weather or visibility conditions. Rotation of runway use is limited to smaller jet or turbo propeller aircraft which do not have a significant noise profile and can utilize a shorter runway.
Changes to flight operations to reduce ground noise would come in the ways departures leave the airport or arrivals approach the airport. Departing aircraft currently leave at angles appropriate for their type of aircraft and flight. Jet aircraft leave at a steep, but comfortable, angle to reach cruising altitude sooner to take advantage of upper level winds or to gain access to a preferred flight lane to their destination. Angles of departure are usually not able to change. Directions of approach and the angles or slope of approach to the runway is dependent upon the aircraft, flight course assigned by Air Traffic Control, other aircraft in the vicinity, wind speed and direction, and weather or daylight. For each runway, there is an approach plate or procedure to reach the end of the runway. These are governed by the FAA and take into account the terrain, predominant wind direction, weather conditions, navigational aids, and other variables. Aircraft on approach to any airport usually follow set alignments over markers as waypoints along their approach to ensure they are not in the way of other aircraft. The approach angle to the runway is determined by the weather and how the aircraft is operating – whether it is operating in a clear all weather condition or in a condition with reduced visibility due to weather or night time operations and variable winds or windy conditions.
Significant changes to the arrival or departure alignment or angle, use of different arrival or departures procedures, and use of different runways in many cases are not possible and will have an unknown impact on the communities surrounding the airport.