It is not all ‘sugar and spice and all that is nice’. Airline companies and aircraft manufacturers vie with each other to provide plush, quiet cabins, smart and soothing colour schemes reflecting an airline brand, ambient lighting that mimics the sky by night or day, luxury seats that effortlessly glide into flattest of beds, ergonomically superior economy class seats, streamlined storage and the best of entertainment on tap, and much more. Basically, every convenience that lets flyers arrive at their destinations, refreshed.
Yet, beneath all the cosmetics is a far serious concern at play – that of safety and survivability. It’s priority number one and will always remain of paramount importance. Designing cabin interiors is pure science with art infused. Cabin interiors are enhanced for comfort and importantly must be rendered safe to travel in. Here, there is an ongoing effort for increasing the chances of survival in case of an accident or incident during take-off or landing. This is made possible by using aviation complaint materials to make or fabricate, amongst other important areas of consideration. Cabin crew training and compliance with regulators’ mandates are equally important to make a cabin experience safe and as accident and incident free as possible. Passenger and crew safety is brought about by proactive safety management, timely hazard identification, risk management, and with prioritising survivability in an emergency situation.
Making airline operations safer
Learning from each other, based on research on past accidents and incidents, crunching tons of data, manufactures, carriers, regulators and airport operators across the globe, work closely to improve overall safety in airline operations. For this, modifications and innovative changes are carried out in the designing of aircraft and cabins, and as per regulator guidelines, newer operating laws are applied for operations to remain airworthy.
Aircraft cabins are fitted with emergency provisions that are life-saving like passenger oxygen supply, emergency equipment, seats, flammability, emergency exits, emergency lighting and escape path markings, and other safety enhancing systems.
Controlling cabin environment, cooling and ventilation requirements, and more recently making cabins safe from the spread of the covid infection, are important issues that are addressed in cabin maintenance and management.
Ensuring cabin safety behind the scenes, are a host of professionals and technical staff whose close cooperation and inputs contribute to achieving safety standards. These are engineering and certification managers, design engineers, airworthiness and certification engineers, program managers, consultants, agency representatives from Federal Aviation Administration, EASA and respective DGCAs who are responsible for airworthiness certification, and other technical and administrative personnel involved.
Survivability is key and cabin safety mandated standards if not adhered to, do not get the necessary certifications and that hampers airworthiness the main eligibility criteria for operating.
“Title 49 U.S.C. empowers FAA to prescribe regulations and minimum safety standards and requires air carriers to provide service with the highest possible degree of safety in the public interest. Air carriers, are responsible for safety management, quality assurance and quality control”, as is mentioned in the faa.gov website.
Likewise, the European Union Air Safety Agency (EASA) and the Director General of Civil Aviation (DGCA)s of various countries would have similar responsibilities and service objectives in place.
Some cases of safer air travel and survivability
Most incidents and accidents occur during take-off or landing, and some events listed below highlight how passenger jet interiors have been reinforced to avoid or contain fatalities: (reference Boeing Aero Magazine)
- In December 2008, an airplane crashed while taking off, ending up on fire in a 40-foot-deep ravine several hundred yards from the runway. There were no fatalities among the 115 passengers and crew, even though the metal fuselage had been breached by fire.
- In August 2010, an airplane crashed while attempting to land during poor weather, breaking into three pieces on impact. There were 125 survivors among the 127 passengers and crew aboard the flight.
The three areas that airplanes are worked upon for safety and survivability are: surviving impact, surviving a fire, and evacuation.
Surviving impact, where survivability is dependent on hugely by the seat design. By remaining in place, the seats are able to absorb energy during an impact. This allows greater chances of survival for the passenger. Again, in order to prevent head injury, the seat back designs protect passenger seated behind a seat from such an injury.
Safety Factor in Seat design
Seat designs have undergone a sea-change in terms of safety and airworthiness. In the 1930s, passenger airplane seats could withstand a static force six times the force of gravity (6g). Today’s seats are required to withstand a 16g dynamic force. A 16g seat is tested in a manner that simulates the loads that could be expected in an impact-survivable accident.
Head injury protection
There is a Head Injury Criterion (HIC) mandated by the U.S. regulator FAA must be adhered to, to provide maximum protection from head injuries which may happen during turbulence or accidents. The head impact with seats or other structures should not exceed this head injury criterion.
Protection from Cabin Fire and Flashovers
Over the years new testing methods are being developed by the FAA for fire proofing large surfaces in cabin interiors such as panels, ceilings, walls, overhead bins, and partitions. August 1988 onwards all commercial aircraft manufactured has had to use panels that display reduced heat and smoke emissions, delaying the onset of a flashover (i.e., the simultaneous or near-simultaneous ignition of all flammable material in an enclosed area). Furthermore, cabin / aircraft interiors are constantly updated with upgrades and refurbished several times, with safer materials in the event of cabin fire. Older aircraft too by default get the newer versions of refurbishment.
Effective August 1990 manufacturers are mandated to apply certain standards such as – maximum peak heat release, that is a limit of a maximum total heat release of 65 kilowatt minutes per square meter, and specific optical smoke density of 200 OSU 65/65/200 fire safety standard as defined by Ohio State University.
Throughout the passenger aircraft interior, manufacturers build in comprehensive fire protection systems, that use the use of fire-protective materials, smoke detection and fire extinguishing systems, and insulation blankets that are burn-through resistant from a fuel fire next to the bottom half of the fuselage.
Evacuating the airplane
The time limit set by the FAA is 90 seconds for evacuation of all passengers from an aircraft. A typical aircraft interior has several built-in features such as escape slides, floor proximity slides that allow rapid emergency handling essential for survivability.
Floor proximity lighting aids airplane evacuation under dark or smoky conditions that pervade an aircraft cabin in the event of a crash. The presence of hot smoke and gases filling up a cabin block out overhead lighting and hence floor lighting marking out an emergency path on the floor of an aircraft cabin assist evacuation very effectively. In fact, according to FAA, such a system betters the evacuation rate by twenty percent in some situations.
Escape slides/Chutes
Passenger airplanes are equipped with automatic, self-inflating slides that are made of fire-resistant materials and tested stringently to ensure 90 seconds limit of evacuation of passengers in an emergency. Safety regulations require 60 persons to be evacuated per sliding lane per minute. Such is the stringent nature of quality checks as the objective is about saving lives. New technologies and research data from past events have gone into developing the most advanced escape slides aiding survivability.
First put into service as the modern-day escape slide in 1971, superior fabrication and a host of tests for durability in tough situations such as burning resistant tests, latest radiant heat requirement tests, resistance to fluids, exposure to sun and many more. The door slides are mandated to inflate in 10 seconds of deployment, with off-wing slides given a 15 second limit. These escape slides are made for all types of aircraft sizes and tested to withstand multiple contingencies.
Testing, Training and more… extensive test programmes are carried out by both the escape slide manufacturer and the airframe manufacturer to ensure the escape slide system meets all performance requirements. And all other aspects of safety and survivability undergo the same regime.
Importantly, IATA’s Cabin Operations Safety Guide can be regarded as the bible for carriers. Best and recommended practices that are benchmarks, are imbibed by managements of airline companies. Regulations rolled out under ICAO’S Annex 6, ensure efficient cabin operations, cabin product and service design, and delivery of same in a safe manner. Cabin Safety is a vital part of any Safety Management System (SMS).
Attending IATA’s annual Cabin Operations Safety Conference (COSC) and similar such, are important events to attend for gaining valuable knowledge and insights, which adds to one’s expertise.
Safety compliance by Airline Manufacturers /Certification and airworthiness
Product certifications are provided by aviation authorities. Aircraft manufacturers ensure compliance through design and certification of products, maintenance and retrofits, flight and cabin crew training. Some examples are Airbus approaches EASA, for various approvals, including monitoring of in-service safety through approved EASA Part-M Continuing Airworthiness Management Organisations (CAMO). Similarly, American plane makers like Boeing will be under the purview of FAA for certification of transport category cabin interiors as enlisted in FAA’s Part 25 Transport Category, which explains aircraft cabin interior safety and crashworthiness regulations and compliance requirements.
Regardless of whether it is a simple modification, a customised business jet for a VIP, or airline passenger seating configuration, airworthiness personnel must understand and adhere to these requirements. While cabin interior emergency provisions are critical items to check off, equally important are environmental, cooling and ventilation standards and their maintenance, as per FAA’s CFR Part 25 Airworthiness Standards and similar.
Continuous audits by regulators, and additionally third-party audits are conducted for quality certifications.
Reference Credit
- Websites of Boeing, Airbus, IATA, ICAO
- mpofcinci.com
- sae.org
