Missing flights - Piaware vs airport stats?

[nospamprl]

I live very close to Mexico City’s airport (MEX) , about 10 miles away and right below it’s approach route. Every plane above my home is displayed in Piaware and viceversa. I get at least a 100NM range, with peaks at around 210NM

I’ve been using Piaware for about 2 years now. My stats page shows about 450-550 daily flights seen by my receiver which is consistent with other receivers in the city, obviously not all seen aircraft are headed to or departed MEX, so I would guess the actual daily operations in MEX should be below that daily average.

Today I heard in the news that airport officials said that during the holiday season they average 1,000 daily flights, so I investigated and found the official airport monthly report in which apparently there are about 30,000-40,000 monthly flights (pages 6 & 9 https://www.aicm.com.mx/acercadelaicm/archivos/files/Estadisticas/EstadisticasNov2021.pdf)
.

What do airports report as an “operation”? I would say either an arrival or a departure, but maybe thay are reporting something else or with a different methodology. One possibility is that they are providing false information, but I don’t think so.

I’m preety sure I’m seeing all incoming and outgoing flights in my receiver (as it is consistent with other receivers in the city), but can’t explain the differences.

[jonhawkes2030]

Flight aware only counts an aircraft once per UTC day. An aircraft could takeoff and land a dozen times and it would only count as one on the stats page.

[foxhunter]

FA counts unique aircraft per day only. That means an cannot appear twice, even if different flights were operated with it on that day.

I am counting seperately the number of flights per day on my device. That covers the same aircraft, but with different flights.

[fhmiii]

@jonhawkes2030

Flight aware only counts an aircraft once per UTC day. An aircraft could takeoff and land a dozen times and it would only count as one on the stats page.

So what you’re saying is, if you live near a major airport hub then you’re probably counting a lot more flights and positions, but since it only counts an aircraft once per day then you won’t see a corresponding increase in the number of aircraft?

[foxhunter]

@fhmiii

but since it only counts an aircraft once per day then you won’t see a corresponding increase in the number of aircraft?

That’s exactly how it works.

I am feeding several sites and i also log the flights in a local database by using the export functionality of ModesMixer2
Comparing the two numbers shows a difference of around 30% and in this database aircraft can show up more than once per day, but with different flight numbers.