FlyerTalk Forums - View Single Post - DCA perimeter exemptions [additional slots at DCA ]
Old May 11, 2024 | 11:06 am
  #52  
Section 107
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Join Date: Nov 2007
Location: WAS
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Originally Posted by TGarza
Does DCA have a hard curfew for flights or a suggested curfew? DAL has a suggested curfew which hasn’t been approved by the FAA.
Originally Posted by BOS TO DCA
Not really. It has a unique "DCA Nighttime Noise Rule" between the hours of 10p and 7a, but it's not even a suggested curfew. I'm not entirely clear on how they measure it, but they do (at least in theory) issue fines to aircraft operators that exceed the noise limit in those hours.
No curfew, the airfield is open 24 hours, the tower is manned 24 hours, and ground operations are 24 hours. There are currently 15 noise monitoring stations (NMS) distributed primarily along the river approach/departure paths.

Curiously, (or maybe because of, you know, Congress) the data from the NMS cannot be used to determine if a particular aircraft violated the noise rule.

In 2000 the FAA established "Stage 3" noise limits. Aircraft are assigned a noise rating during the FAA Noise Certification process for the aircraft type. But the DCA Noise Rule limits are more restrictive than the stage 3 limits and the DCA noise rule was authorized to remain in effect after FAA transferred the airport to the Airports Authority (MWAA - not to be confused with Metro/WMATA). So, a violation will occur if any aircraft of a certain type arrives/departs during the restricted time period regardless of the actual noise created by the specific aircraft itself.

Put another way, the NMS are used to monitor noise from the airport but not used for enforcement. Enforcement is conducted by simply determining if a specific type of aircraft arrived/departed during the restricted hours.
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