In some cases there can be a discrepancy between the number of complaints that Airnoise users have created and the number of complaints reported by the airport or airport authority. Sometimes the airport will report more, but most often they will report fewer complaints than Airnoise shows.
Regardless of whether a complaint is submitted to the airport's official complaint system, we believe that any complaint generated by an Airnoise user is a legitimate complaint, even when we can't positively identify an aircraft. If someone indicates that they suffered intrusive aircraft noise at a specific time, in a specific place, that's sufficient to create a complaint. For this reason, we report the counts of all complaints generated by Airnoise users.
When Airports Report More Complaints than Airnoise
In the case of the airport authority reporting more complaints, realize that any complaint submitted directly to an airport and not via Airnoise will not show up as a complaint in Airnoise. Airports usually offer several ways to file complaints, for example, via their web form, via email, or with a phone call. If someone files a complaint using one of those methods there's no way for Airnoise to know about it. We only report the count of complaints generated in our system. Also, some airports don't differentiate between complaints filed through Airnoise and those that are, so all complaints get lumped together.
When Airports Report Fewer Complaints than Airnoise
More often, though, when the airport does group complaints by their source, including complaints from Airnoise, the count of complaints they've received from Airnoise can be lower than the number of complaints shown on your Stats page in Airnoise. There are a couple of reasons why this discrepancy exists:
For some airports, Airnoise will not submit a complaint if our system can't positively identify an aircraft.
Airnoise users can choose whether or not to automatically submit their complaints to the airport. If a user chooses not to submit a complaint, even if an aircraft is identified in it, that complaint will not show up in the airport's tally.
Occasionally a technical issue will occur in an airport authority's system that prevents a complaint from being submitted by Airnoise. Our system makes multiple, best-effort attempts for up to two weeks to submit every complaint, but sometimes an issue isn't resolved within two weeks and a complaint won't be submitted. This happens very rarely.
Some airport noise complaint systems require users to create a separate login in their system before they will accept complaints for that person. If a user doesn't create that account, or doesn't properly add their credentials to Airnoise, our system can't submit the complaint into the airport's system.
Airports also sometimes will only accept recent complaints (say, within the last 30 days), so if a user doesn't submit complaints or setup their credentials for us to submit complaints to airports that require it within that window, we may not be able to submit those complaints.
Some airports use commercially-provided systems to track airport noise and noise complaints. Those systems have access to the FAA's full aircraft tracking data, so they can usually correlate air traffic near a person's house when a complaint is filed, even if Airnoise was unable to positively identify an aircraft at the time the complaint was generated. For those airports, Airnoise will still submit the complaint even if we can't identify the suspected aircraft.