If you've been keeping an eye on FlightRadar24.com in the run-up to the 2023 Paris Air Show, you may have seen that aircraft have been undertaking validation flights over the past few days. If you've been looking really closely, you may have noticed that these aircraft appear not to leave the ground.If you're wondering what on Earth is going on, then you're not alone. Thankfully, the folks over at FlightRadar24.com know the answer, and it's all to do with how close Le Bourget's is to Paris' busiest airport, Charles De Gaulle (CDG), which is just six miles away.
Avoiding chaos
If you look at the Boeing 777X's validation flight track earlier today, you'll see that it seemingly never left the ground. However, its vertical airspeed tells a different story, drastically fluctuating between positive and negative figures.
According to FlightRadar24.com, the reason for this is that aircraft performing at Le Bourget intentionally set their transponders to "ALT RPTG OFF," or altitude reporting off. According to the flight tracking experts, this is done so that aircraft flying into Charles De Gaulle do not get continuous traffic alerts on their approach.
What's actually going on?
Of course, the aircraft doesn't remain on the ground and does take to the skies. While each flight will be slightly different, we can gauge a rough picture of what is going on with the Boeing 777X thanks to a different air show.
The Farnborough Airshow is not particularly close to any major airport approach corridors, and thus aircraft are free to broadcast their altitude without any impact on commercial traffic. The Boeing 777-9's performance last year was no exception, with the aircraft recorded as reaching a maximum height of 1,500 feet on the show's first day. You can see its altitude graph above and how it looked in the image below.
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What are validation flights?
Validation flights occur ahead of air shows when relatively few people are around the location. It allows those performing at the air show to prove to organizers that their display fits the routine described and won't cause an unnecessary risk when the ground nearby is packed with hundreds of thousands of airshow visitors.
Did you know why Le Bourget display aircraft aren't broadcasting their altitude? Let us know in the comments below!
Sources: FlightRadar24.com, FlightGlobal