Passengers on an IndiGo flight to Varanasi were immediately evacuated minutes before the take-off from the Indira Gandhi International Airport in Delhi on May 28 after a note that mentioned “bomb” on it was found in the plane’s lavatory. The threat was declared as a hoax at 11 am, and the flight departed after that.
What is interesting about the incident is how it caught the attention of the people when visuals of evacuation appeared on the Internet. In one of the videos, the pilot was seen sliding out of the aircraft on the emergency slide. In another video, passengers were seen using the emergency slide at the rear-end of the plane.
A third video showed an elderly woman was being helped by the cabin crew out of the emergency exit of the plane on to the wing in order to use the emergency slide.
What is an Evacuation Slide?
An evacuation slide is an inflatable aircraft escape used to evacuate passengers safely during an emergency like fire or water that make exits unsafe. There are four types of slides: land slides, rafts, off-wing exit ramps and combination exit ramps and slides.
The inflatable slide helps passengers descend to the ground from an aircraft exit door. In case they cannot use the doors, they can try to reach either of the aircraft wings. From there, they can use the slide to reach the ground.
The raft slide does the same job, but it used when the aircraft has to land on water.
The exit ramps are used to help passengers move from certain overwing exits to the wings, if that path looks better for reaching the ground. The inflatable exit ramp/slide is there to assist in descending from an overwing exit or aeroplane wing to the ground. It is a combination ramp and wing-to-ground device.
What are They Made Of?
The escape slides are made from carbon fibres and a nylon material coated in urethane and sprayed with gray aluminized paint for fire resistance. Manufacturers use strong fibers to ensure passengers cannot tear the slides and remain safe during evacuation.
Emergency escape slides are located inside cabin doors or in external fuselage compartments. They are light and compact for easy storage and quick deployment. High-pressure gas carbon dioxide or nitrogen gas containers rapidly inflate plane evacuation slides after a crew member opens the aircraft door during flight, as the slide connects to the door with an interior lever called the girt. An emergency escape slide will pop out horizontally when fully inflated before lowering to stand at 25 feet.
Emergency escape slides typically last 15 years with proper maintenance.
How to Deploy Evacuation Slides?
According to the US’ Federal Aviation Administration (FAA), escape slides should be deployed with the ability for all passengers and crew members to exit the plane in a maximum of 90 seconds.
An evacuation slide must be deployed when the distance between the ground and the flight exit door is six feet or more. The European Union Aviation Safety Agency’s guidelines say a slide should be automatically deployed, once the door is opened. The slide must be inflated between six and 10 seconds, depending on its location.
As per the FAA, the escape slides should be deployed in all weather conditions from -40 degree Celsius to as hot as 70 degree Celsius. The slide should be able to sustain a rainfall of up to one inch an hour and winds up to 46 km per hour.
Previous Incidents
In June 2016, the engine and right-wing of a Singapore Airlines Boeing 777-300 caught fire. Rather than using the evacuation slides, crews decided to evacuate guests with a set of mobile stairs. When using the stairs, it took 40 minutes for the crew to make a decision, the stairs to be positioned and all crew and passengers to safely evacuate, according to a blog post by California-based HDR Aero Systems.
In another incident, an Asiana Airlines Boeing 777-200 crashed and caught fire on its descent to San Francisco. After 93 seconds, crew members deployed the first two emergency slides. While the evacuation wasn’t flawless and the crash was so severe it resulted in three fatalities, crew members and passengers evacuated the aircraft in a fraction of the time it took to evacuate with stairs.
In August 2016, the engine of an Emirates Boeing 777-300 in Dubai detached from the wing, causing a large fire and requiring evacuation. While the slide deployed, the wind blew it back up against the fuselage, blocking the exit. Internal baffles and half-tie restraints prevent similar incidents. Further, passengers tried to take baggage with them during evacuation.
In January, 2024, a Japan Airlines flight successfully evacuated all 379 passengers even as the plane caught fire after colliding with a Coast Guard plane during its descent at Tokyo’s Haneda airport. All slid down the escape chutes within 20 minutes of the landing as smoke filled the cabin of the burning aircraft. The Japan Airlines crew faced various obstacles during the evacuation, including limited usable exits, high passenger density, poor visibility due to smoke, and technical difficulties with the aircraft and communication systems.