Why is aviation safety under scrutiny? | Explained

The story so far: The issue of air safety played out under intense media scrutiny following two aviation incidents. In the first instance, on January 2, 2024, at around 5.45 p.m., a Japan Airlines (JAL) Airbus A350-900 collided with a Japan Coast Guard De Havilland Canada Dash 8 after its landing, with both aircraft catching fire. While all 367 passengers and 12 crew on the JAL aircraft escaped, there were five fatalities (of a total of six passengers) on the Coast Guard plane that was waiting to depart for the Niigata base with relief supplies following an earthquake in Japan. In the second instance, on January 5, an Alaska Airlines Boeing 737 MAX 9 with 171 passengers and six crew, was departing from Portland, U.S., when a window panel ‘door plug’ blew out mid-air causing depressurisation. The crew put the aircraft into an emergency descent and returned to base. No major passenger injuries were reported.

What are the new developments in the Boeing case?

The incident has brought back renewed attention to the Boeing 737 MAX’s troubled flight safety record, with concerns being raised about quality control and the aircraft’s manufacturing processes. On January 12, the Federal Aviation Administration in the United States announced more “oversight on Boeing” which will be in addition to its probe into the incident. The FAA is to “evaluate Boeing’s compliance with its approved quality procedures”, apart from an “an assessment of safety risks and quality oversight”.

The FAA could even be “exploring the need for an independent third party to oversee inspections and quality in Boeing”.

The National Transportation Safety Board (NTSB) too is probing the incident, with its focus on the cabin pressure control system. Boeing CEO Dave Calhoun had told Boeing employees earlier in a meeting at the company’s factory in Renton, Washington, where the 737s are assembled, “We’re going to approach this – number one – acknowledging our mistake.”

The FAA has added that every Boeing 737 MAX 9 with a plug door would remain grounded till there was a thorough review to ensure its safe return to operation. Under the FAA’s Emergency Airworthiness Directive, which affects about 171 jets across the world, airlines will be required to inspect aircraft (up to eight hours a plane).

The door plug is a space in the fuselage that allows for an additional emergency exit door to be installed. In the Alaska incident, parts of the seat next to the door plug were damaged, while some seat frames were found twisted. The door plug was found later in a neighbourhood in Portland. A few mobile phones of passengers were sucked out.

Alaska Airlines, and later United Airlines, reported their aircraft technicians finding “loose hardware” on some aircraft.

India’s Directorate General of Civil Aviation also reported an unidentified Indian operator of the Boeing 737 MAX finding a missing washer during a maintenance inspection. Three airlines in India, i.e., Air India Express, Akasa and Spicejet, operate the 737 MAX 8. This follows a Boeing directive in December 2023 asking 737 MAX operators across the world to carry out checks after a loose bolt was found in the rudder control system of a 737 MAX (the airline has not been named).

What did the Airbus incident show about safety?

The JAL Airbus was flying from Sapporo New Chitose to Tokyo Haneda, which is the world’s third busiest domestic airline route (according to aviation data). This is also the first complete hull loss of an A350.

However, it was the survival of all the passengers on a new technology aircraft that drew attention, in turn highlighting the importance of crew training, the critical response time of fire and rescue teams and the advances in aircraft manufacturing technology. In the JAL incident, as the aircraft’s public announcement system malfunctioned, the cabin crew had to conduct the evacuation using megaphones and voice commands. All passengers were evacuated through three emergency exits.

What about newer aircraft technology? What are the insights that the JAL incident can offer?

Aviation commentators and experts have highlighted a series of factors in the aviation industry today that ensured the survivability of passengers. These include stringent crew training in emergency procedures to the characteristics of materials now being used in aircraft architecture, and even the response time of ground fire and rescue teams.

There is increasing use of composite materials in newer aircraft being made by Airbus (A350) and Boeing (787 and 777), which ensure a combination of durability, strength and low weight. In the A350, for example, more than half the plane’s structure is composite, with the use of advanced materials such as carbon-fibre reinforced plastic (CFRP). The JAL fire was a real world test for such an aircraft, and the forensic analysis will offer valuable technical insights to investigators and manufacturers.

In the Boeing 787 programme, for instance, there have been computer simulation models of the behaviour of composite materials in extreme situations such as a fire or crash, but which have left structural experts divided. But in fire tests conducted by the FAA in November 2007, plastic composites were shown to withstand fire much better than metal. Boeing also issued official guidelines to airport firefighting departments on the use of standard techniques to put out an 787 fire, which even included aspects such as the “toxicity perspective”. An aviation expert says the JAL fire will provide insights into this as well.

Professor Graham Braithwaite, Director of Transport Systems, Cranfield University, U.K. told The Hindu that there are many things that have changed over the years to try and ensure that aircraft can be successfully evacuated, especially when a fire occurs. In the U.K., the most significant accident involved a British Airtours Boeing 737 at Manchester airport in August 1985. Despite fire fighters responding quickly, passengers panicked in the resultant fire and smoke, and were stuck around the exits. Many recommendations came from this investigation on how an aircraft cabin should be designed. These included increased space for the overwing exit rows, clearer signage for exits, and even changes to cabin materials to reduce the likelihood of poisonous fumes.

The accident also led to a series of research studies by Professor Helen Muir into the behaviour of passengers, which in turn was used by the major aircraft manufacturers to help them understand the best configurations to ensure a rapid evacuation.

In today’s world, says Prof. Braithwaite, aviation safety regulators require new aircraft types to meet a standard whereby all passengers can be successfully evacuated in 90 seconds or less, and with only half of the exits in use. The role of the cabin crew is very important with research showing that clear commands make a big difference. Passengers can easily become shocked, panicked, and confused. The aim is always to maximise the speed at which people get off the aircraft.

It must also be remembered, says Prof. Braithwaite, how important the airport rescue and firefighting team is — it is expected to reach anywhere on the airport within two minutes in order to clear and protect the exits, and fight the fire.

“The JAL fire and evacuation benefited from all of these lessons, but there are a few more factors. Japan Airlines is globally renowned for its approach to safety and the crew at Haneda did a fantastic job of managing this emergency. They were perhaps helped in part by how compliant the passengers were with their instructions, for example, in not bringing their luggage with them during the evacuation.”

The aircraft also seems to have performed very well, says Prof. Braithwaite. Although the composite body eventually burned quite fiercely, this was only after it had successfully done its job in protecting those on board. The composite structure seems to withstand ‘burn through’ and the interior did not generate poisonous fumes, when compared with the Manchester fire.

What about crew training?

An official spokesperson for Japan Airlines told The Hindu that crew training (as in any airline) is of vital importance, with emergency training for cabin crew covering written confirmation of knowledge regarding emergency measures, daily safety tasks, emergency equipment, and various equipment. Crew also go through case studies where there is door training for each type of equipment (land and at sea scenarios), and comprehensive exercises that cover the occurrence of an emergency to evacuation, where operating crew members undergo joint training. Cabin crew undergo training once a year in regular rescue training.

There is also emergency evacuation training for flight deck crew (pilots) which covers general rescue procedures, aviation security, instructions for door and emergency equipment usage for each aircraft type, and emergency evacuation methods.

Further to this, there is aircraft type transition training as well as regular rescue training that is conducted jointly with cabin crew. These involve a few case studies using an emergency situation based on past incidents (learning from accident examples and conducting discussions), and a series of case studies (sudden, on-land, sea, and anticipated scenarios) which goes through the complete process, from the occurrence of an emergency to evacuation/resolution.

The spokesperson added that all operating crew had to attend co-pilot promotion training, type transition training, and regular rescue training. In addition to this, after attending the initial co-pilot promotion training, each individual is assigned a reference month, where it was mandatory to attend the annual regular rescue training programme.

What are the key safety improvements?

In his comments to The Hindu, Dr. Hassan Shahidi, president and CEO, Flight Safety Foundation, Washington DC-Baltimore Area, U.S., said the incident validates the requirement of flight and cabin crew members completing intensive training and checking on their capability to handle emergencies, including emergency evacuations. Each year, crew members also receive recurrent training and testing in emergency evacuation procedures, which are increasingly being done in cabin simulators that can replicate the conditions that a crew member may encounter during an evacuation including limited visibility due to smoke, and unusual attitudes an aircraft may be in after an incident. The simulators allow the airlines to replicate the various scenarios that crew members may face.

It is also important for passengers to realise that they play an important and active role in their own safety, says Dr. Hassan Shahidi, as this incident has demonstrated that not all exits are always going to be safe to use.

The Flight Safety Foundation also shared Federal Aviation Administration directives, on changes made in cabin materials and structures over the years. The first is improved flammability of seat cushions, with a FAA rule (1984) requiring that cushions installed on seats comply with a more stringent flammability test standard using a ‘2 gallon per hour’ kerosene burner. The rule applied to all new transport aircraft certification programmes, which was later extended to aircraft manufactured on or after November 26, 1987. The new material was found to provide up to a minute more of additional time for evacuation when compared to earlier. All existing aircraft seats in the U.S. meet the improved standards. And the international aviation community too has followed these standards, the Flight Safety Foundation says.

The second is floor proximity emergency escape path marking. The FAA found that this could improve the evacuation rate by 20% in a situation where there is much smoke in the cabin.

The third and fourth are lavatory smoke detectors and lavatory fire extinguishers, introduced in 1986 and 1987, respectively. These are automatic devices.

The fifth is the use of halon fire extinguishers (since 1986), where the FAA requirement is of having halon extinguishers on board in addition to the other required extinguishers.

The sixth is cargo compartment liners which test the burn through resistance fire test criteria for compartment ceiling and wall liners.

The seventh is the use of improved interior materials for large surface area panels such as the walls and even overhead bins. The aim was to delay a flash fire, thus giving passengers and crew more time to evacuate. The standard was that after the year 1990, all panels would pass the standard for reduced heat release as well as a smoke emissions test standard.

The eighth area of improvement was the use of better seats. Under FAA regulations, seats were to comply with the 16g dynamic standard (from the year 2009).

The ninth is improved access to exits, especially Type III (over wing), where there were specific minimum standards for the passageway from the aisle to the exit. As a result, tests showed a better evacuation rate — almost 14% faster than earlier.

The tenth area is cargo compartment fire detection/suppression which was made mandatory in passenger aircraft since 2001.

Finally, there were changes to thermal/acoustic insulation in order to meet to meet a new flame propagation standard (from 1999). There was also another test standard for the resistance of the insulation to burn through from an external fire made mandatory for aircraft being flown in the U.S.

Thus, FAA research and upgrades to aircraft have had a role to play in better passenger survivability.

According to a senior Airbus official, aircraft certification requirements and processes are among the toughest in any industry, and it is up to the aircraft manufacturer to demonstrate that all safety requirements are met. He said the 90-second (evacuation) rule applies to all aircraft no matter what material the fuselage is made from. The evacuation test was indeed part of the A350’s certification, he told The Hindu. (Air India received its first Airbus A350-900 recently.)

“In aviation, safety and the safe operation of aircraft are paramount. This is why the aircraft certification requirements and processes are among the toughest in any industry. The certification of an aircraft spans several years with every step of the process overseen by the certification authorities.”

A senior airline commander (close to 20,000 hours of flying and 5,500 hours on the Airbus A320 simulator as trainer/examiner) says that the 18 minute event — it took the JAL crew 18 minutes to get every passenger off the aircraft — points to the design aspect linked to delaying the effects of a fire.

He says that for a given aircraft type, and its age, the nature of the impact decides how much damage is caused. The spread of a fire also depends on the fuselage, the remaining aircraft fuel, the wind/external environment and firefighting response.

His final word is that while no aircraft can be made 100% fire proof or collision proof, it is a series of factors that could aid better passenger survivability.