The main sources of noise at airfields are flight operations or pre‐flight and maintenance run‐ups . Computer models are used to develop noise contours based on information about these operations including : type of operation ( arrival , departure , and pattern ); number of operations per day ; time of operation ; flight track ; aircraft power settings , speeds , and altitudes ; number and duration of maintenance run‐ups ; terrain ; surface type ; and environmental data ( temperature and humidity ).
The Air Force considers how its operations impact the local community by calculating the day‐night average sound level ( DNL ). The DNL averages the noise levels of all aircraft operations that occur with a 24‐hour period . To assist the communities in land use decisions , the DOD uses decibel noise contours to illustrate the exposure to noise associated with aviation activities . For land‐use planning purposes , DNL noise zones are provided in increments of 5 dB between 65 dB and 85 dB .
Noise contours associated with the Seymour Johnson AFB were developed in 2011 based on existing and projected aircraft and are illustrated on Figure 3‐14 . The relatively high noise levels near the runway ( greater than a DNL of 85 dB ) result from departure operations .
In total there is approximately 18,777 acres in a noise zone associated with Seymour Johnson AFB operations . Of this land , 15,955 acres is located offinstallation :
• 8,175 acres of land in the 65‐69 DNL Noise Contour
• 4,622 acres in the 70‐74 DNL Noise Contour
• 2,316 acres in the 70‐74 DNL Noise Contour
• 680 acres in the 80‐84 DNL Noise Contour
• 162 acres in the 85 + DNL Noise Contour
Explosive Safety Quantity Distance Arcs The Explosive Safety Quantity Distance ( ESQD ) a has been assessed based on the impacts of the t stored . These arcs represent the setback distan or handling where inhabited facilities cannot be distances are based on the quantity and type of distance from the ordnance facility from which t damage is greatly reduced . Though the ESQD arc installation perimeter , the ESQD arc areas are un agreement between the Air Force and property development and habitable structures in this are Seymour Johnson AFB are illustrated on Figure 3
Seymour Johnson AFB has established ESQD arcs of the installation as shown in Figure 3‐15 . In ge beyond the installation boundary , easements are residential development . At the installation , the buildings within the ESQD arcs must be limited t effective mission accomplishment .
Bird / Wildlife Aircraft Strike Hazard Airports , due to the nature of their operations , t grassy areas where wildlife congregates . Additio golf courses , are often situated near airports bec the height and density restrictions imposed by a golf courses also have large , open , grassy areas a water – another wildlife attractant . Given the fat occur as a result of a bird and / or wildlife strike , recommendations for managing these types and wildlife attractants near airports .
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