Located in the Paris suburbs, Paris Orly Airport (LFPO) is the second busiest airport in France. Surprisingly, its weather system is still running on Windows 3.1, software from over 20 years ago!

Orly Airport’s weather reporting system is called DECOR. On November 7th last month at 09:30, this system malfunctioned, preventing controllers from obtaining Runway Visual Range (RVR) data for pilots. At the time, there was dense fog surrounding the airport. Without RVR data, it is impossible to determine if takeoffs and landings are safe. Consequently, from 09:30 to 10:30, the airport was forced to close its runways, and 10 flights had to divert to Charles de Gaulle International Airport.

Windows 3.1 was released in 1992; I suppose there aren’t many people who have used it. It is quite unexpected that such an antiquated system is still performing such a critical role at an airport today. After all, if it breaks, finding spare parts for repairs is not easy. It is said that there are only 3 engineers left capable of maintaining the DECOR system, and one of them is retiring at the end of this year, so finding personnel to repair it in the future will be a major issue. Even more surprisingly, Charles de Gaulle International Airport also uses the same DECOR system. If that were to fail as well, the impact on airlines and passengers would be much greater.

Speaking of which, I first used Windows 3.1 myself around 1993, and I probably stopped using it after Windows 95 was released. Back then, there were very few applications for Windows; perhaps the most frequently used one was Microsoft Word. But most applications were still DOS-based. For some memory-intensive games, we had to switch autoexec.bat and config.sys and restart. Although it was troublesome, looking back now, it was actually quite fun.

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