You may have seen cabin crew pull a metal lever at the doors and attach a small red ribbon to the exits during the final stages of a plane’s preparation for takeoff. Although this ribbon seems to be of little use, it is actually a critical piece of equipment that can save someone’s life…
This ribbon is used to inform emergency services, especially those trying to enter from outside the aircraft, that a door is “loaded” and opening it could pose a serious danger. A “loaded” door indicates that the aircraft’s evacuation slide is engaged and ready to open. In this case, opening the door will cause the slide to burst out and inflate rapidly, creating a serious crushing hazard for anyone standing in front of the door.
All commercial passenger aircraft must have equipment that allows everyone on board to be evacuated in less than 90 seconds. The evacuation slides developed for this purpose must be able to operate at temperatures between -54 and +71 degrees Celsius and even against winds of up to 46.3 kilometers per hour, inflating to be ready for use in six seconds.
The installation process carried out by the cabin crew by pulling the bolts on the doors ensures that the slide system is activated as soon as the door is opened. However, when an undesirable situation occurs and external emergency services need to enter the plane after the plane lands, this little red ribbon is the only information tool they can use to understand at which doors the slide is installed or loaded and ready to be opened.
When a door is opened, compressed carbon dioxide and nitrogen gas create a powerful explosion, and a series of aspirators inside the slide also cause the slide to instantly inflate by up to a third. Additionally, this process creates a vacuum that draws surrounding air into the extractors through the louvers, which close after a few seconds when the slide is fully inflated.
Fortunately, the vast majority of flights arrive and land at their destination without any problems, so this little ribbon’s duty is rarely needed. Removing the ribbon is also part of the protocol followed by the cabin crew after landing, disabling the slide system.
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