A technical failure occurred in the system, and Heathrow Airport in the UK implemented flow control.

On September 20th, local time, Total TV reporters at the UK's largest portal airport, Heathrow International Airport, saw that the departure hall of Terminal 2 was crowded. To avoid overcrowding and potential safety hazards, the airport has implemented crowd control measures for passengers entering the terminal. Airports in several European countries including the UK, Belgium, and Germany reported technical issues with their check-in and boarding systems on the 20th, affecting operations and potentially causing travel delays for passengers. Heathrow Airport in London, UK, issued a statement on social media saying that Collins Aerospace, a company providing check-in and boarding services for multiple airlines at airports in several countries, experienced technical issues leading to passenger boarding delays. The company is currently working to quickly resolve the issue. The airport has deployed additional staff in the check-in area to assist and minimize the impact on passengers' travel as much as possible. UK Transport Minister Heidi Alexander stated that she is aware of the situation and closely monitoring developments. According to European media reports, Collins Aerospace has stated that they are aware of network-related interruptions affecting their software at specific airports.