A still from a passenger video taken during the evacuation of the Emirates aircraft showing passengers opening overhead lockers rather than exiting the aircraft. A safety expert might also query the wisdom of passengers stopping to film the evacuation (WhatsApp).

During the recent emergency evacuation of the Emirates 777 which caught fire in Dubai, a number of passengers endangered their safety and those of others by stopping to collect their luggage. BILL READ FRAeS looks at some of the ideas being proposed to prevent such actions reoccurring and how it may be time for a rethink of the regulations governing aircraft emergency evacuations.

“We noticed something wasn’t right when the landing started taking place."
"People were screaming and we had a very hard landing."
“The engine blew away right after landing. As soon as everyone got out, the plane blew up.”
“In no time the cabin was filled with smoke. The emergency door was forced open."
"We left by going down the emergency slides and as we were leaving on the runway we could see the whole plane catch fire. It was horrifying.”

The above comments come from interviews with passengers in the news reports of the recent accident on 3 August in which an Emirates Airlines Boeing 777-300 caught fire after crash landing at Dubai Airport. The 300 passengers and crew aboard the aircraft were fortunate in that they were able to evacuate the aircraft with no casualties - but the aircraft was almost completely destroyed in the subsequent fire and an airport firefighter was killed from an explosion during the rescue efforts.

However, the accident created a storm of controversy on social media after it was revealed that a number of passengers had stopped to collect their hand luggage before leaving the aircraft - despite pleas from the cabin crews to exit as quickly as possible. Incidents of passengers delaying emergency evacuations to collect their luggage have also occurred in previous aircraft emergency evacuations. Recent incidents include an Air France A340 which overshot the runway at Toronto in 2005, an Asiana 777 which crashed on final approach to San Francisco, a Delta Air Lines MD-88 which veered off the runway at New York LaGuardia airport in March 2015 and a British Airways 777-200ER which experienced an engine failure at Las Vegas airport in September 2015. There have also been many incidents before these. A survey conducted in 2000 by the US National Transportation Safety Board (NTSB) of passengers and flight attendants involved in 46 different aircraft evacuations (http://www.ntsb.gov/safety/safety-studies/Documents/SS0001.pdf) found that almost 50% of people in an evacuation had tried to take a bag. Those surveyed said that passengers retrieving bags caused the most delays to evacuation while flight attendants reported arguments with passengers over baggage and cases of having to move baggage out of the way or throwing bags out of the exit. There was even one incidence of a passenger trying to exit with a guitar.

Why take your luggage?

Is your life really worth risking for this? (Mattes)

The argument against passengers stopping to collect luggage is a simple one. Not only does it delay everyone from leaving an aircraft when seconds may count between life and death but loose luggage can also cause obstructions within the cabin and may damage the emergency slides as well as injuring people using them. This is particularly dangerous in the event of a fire where seconds are precious. Post-crash fires are one of the most critical threats to surviving an accident, as they can cause not only thermal injuries but also death from smoke inhalation, as well as leading to a deterioration in environmental conditions within the cabin which could limit passengers’ ability to exit the aircraft.

So, why do passengers stop to get their luggage? That there is a natural human temptation to collect belongings can easily be demonstrated by anyone who has participated in a practice fire drill when many people stop to put on coats or collect their bags. But why does it happen in situations that are obviously real emergencies and lives are at risk if you hesitate?

One factor might be a lack of perceived threat. If there is no panic and the inside of the aircraft cabin appears to be under no immediate threat (even if it isn’t in reality), then there is less incentive for passengers to get out quickly. It passengers are queuing in the aisles to get off the aircraft, the incentive to take their belongings with them is greater.

Another factor is what is actually inside the hand luggage. While some passengers like to take most of their belongings on board the aircraft with them to save on additional charges for hold baggage or queuing at baggage reclaim, others will restrict their carry-on luggage to items which might be needed during the flight. These items may also include identity documents - everyone is likely to have a coat or bag with their passport inside it - laptops with business files, essential medication, money or papers relating to their holiday or business. When an emergency occurs, some people may also be concerned about what happens to them after they leave the aircraft if they have no money or identity documents. Passengers consulted in the NTSB survey stated that their primary reason for grabbing bags was for money, wallet, or credit cards (111 passengers) while other reasons included job items (65), keys (61), and medicines (51).

Preventative measures

The new Irkhut MC-21 aircraft can be fitted with central locking for luggage bins. (Irkhut)

What can be done to prevent passengers from risking the lives of themselves and others by delaying evacuations? Various suggestions have been proposed to try and deal with the problem. One is that there should be a ‘central locking’ system on the overhead luggage bins which is activated during take-off and landing. The Russian designers of the new Irkhut MC-21 airliner have even included such an automatic locking system for overhead bins as an option for potential purchasers. However, there was a recently reported incident aboard a Cathay Pacific aircraft in which a passenger ripped off a ceiling panel thinking it was a luggage bins which suggests that, even if the bins were locked, some passengers would still try to get into them. There are also potential safety issues in situations where the lockers suddenly need to be opened, such as cabin crew needing to access equipment or a lithium battery fire in a computer laptop.

Another suggestion is to penalise passengers who take their luggage with them - although how this could be enforced during an emergency situation is not clear. However, stopping passengers once they have collected their luggage is acting too late. One conclusion reached by the 2000 NTSB safety study was that trying to part passengers from their luggage once they had reached the exits caused further delays and advised cabin crew to ensure that passengers are prevented from taking luggage before the start of an evacuation.

Teague's Poppi future aircraft interior concept proposes greatly reducing the size of luggage bins. (Teague)

There is also been an idea to ban passengers from taking hand luggage onto an aircraft altogether. Design studio Teague recently came up with a future cabin interior concept which had very small luggage bins for personal belongings only - although these would still be items which passengers might try to retrieve in an emergency. However, the idea of restricting or prohibiting hand luggage is not likely to find favour with passengers who do not want to be parted from their belongings for fear it will be lost, sent to the wrong destination or pilfered. Current rules from certain carriers to charge extra for hold baggage also does not help. Possible solutions put forward to encourage passengers to put their bags in the hold include attaching smart tags to luggage so that passengers can use their smart phones to see that it is with them aboard the aircraft.

Emirates' 777 safety instructions includes a reference to no bags to be taken during evacuations. (Emirates)

Another area of debate has been over the content of the pre-flight safety briefing to passengers and that they should include more emphasis on not taking luggage in an emergency situation. One idea proposed on social media was to depict simulations of two contrasting scenarios, one in which everyone leaves the aircraft in a quick and organised manner and the other in which people stop to get their luggage and people die. However, while the use of such ‘shock tactics’ might well get the safety message across, it is also likely that airlines would get into trouble for alarming passengers. There is also the problem that many passengers do not pay attention to the pre-flight briefing - statistics from the 2000 NTSB survey showed that 50% of passengers did not pay attention to safety information.

An alternative idea is to make it more obvious that an emergency situation is in progress with a pre-recorded alarm which goes off in the cabin during an evacuation - including instructions on not stopping to take luggage. However, this could also run the risk of creating panic when it is not needed and could interfere with evacuation instructions from the cabin crew - which may have to vary depending on the nature of the situation.

Evacuation tests

The trial evacuation of the Airbus A380 resulted in 33 injuries from jumping down the inflatable slides. (Airbus).

Current rules for emergency evacuation demonstrations require aircraft manufacturers to conduct full-scale evacuation demonstrations for new or modified aircraft within a time limit of 90 seconds (the time taken for fire to engulf an aircraft) using 50% of the exits. The purpose of the demonstration is to validate crewmembers' abilities to execute the established emergency evacuation procedures and to ensure realistic assignment of functions to the crew.

The regulations for evacuation trials require that the maximum number of passengers for the aircraft present with a representative sample of different ages and sex. The cabin and the surrounding area must be in ‘dark of night” conditions with the only illumination coming from emergency lighting. Carry-on baggage, blankets and other passenger belongings equivalent to half the actual capacity for the aircraft is placed in the cabin aisles and exit access as minor obstructions.

However, some commentators have argued that such tests are unrealistic because they do not include all the factors that would be present in a real emergency. Participants in evacuation trials are not representative of typical passengers in that they are all physically fit, ready to co-operate and mentally prepared for the incident. While it might be possible to exit an aircraft in under 90 seconds in test situations, it might be a very different experience with smoke or flames in the cabin, no lights to see by and panicking passengers.

Some practical trials have been carried out to try and make trial evacuations more realistic. In 1985 there was an accident at Manchester Airport in which 55 people were killed trying to evacuate a British Airtours 737 which caught fire while preparing to take-off. Air accident investigators discovered that many passengers had died because they had become wedged into a gap near one of the exits. Following this incident, the UK Civil Aviation Authority (CAA) commissioned Cranfield University in 1987 to conduct a number of experimental research studies on issues of cabin safety. Prof Helen Muir from Cranfield organised a series of evacuation simulations in which volunteers were paid money for the speed in which they left the aircraft. Following these tests, aircraft doors were redesigned to make them easier both to reach and to open.

Such tests are not without risk. During the Cranfield trials people became wedged together in the over-wing exit and two simulations had to be halted after a volunteer fell over and was in danger of being trampled. When Airbus conducted the passenger-evacuation test on the A380, although all 873 passengers and crew exited the aircraft in under 90 seconds, 33 participants required medical attention from friction burns while jumping down the inflatable slides.

There is, therefore, a limit on how realistic live tests can be - such as simulating smoke or fumes - without running the risk of injuries. There is also the difficulty of modelling human behaviour. In an emergency situation, people will react in different ways. According to Airbus’ Flight Operation Briefing Notes for unplanned ground evacuation, common passenger reactions include panicking, freezing up, not being aware that danger exists, pushing and exiting with carry-on baggage. A study published by J Leach in 2004 (Why people 'freeze' in an emergency: temporal and cognitive constraints on survival responses) which analysed 11 marine and aviation accidents suggests that passenger behavioural responses can be separated into one of three categories: those who keep calm and can react rationally (10-15%), those who are ‘stunned and bewildered’ (75%) and people who display ‘counterproductive behaviour’.

If it were possible, it might be informative to conduct evacuation trials in which participants are given instructions to behave in particular ways. These could include those who stay calm, those who panic or stay still and different language speakers who do not understand instructions from cabin crew. Participants could also roleplay family groups who stay together, passengers with disabilities and those individuals who stay to collect their hand luggage and use their phones to film each other.

The virtual option

airEXODUS passenger evacuation software can simulate passenger behaviour. (FSEG)

An alternative solution is to conduct computer-simulated ‘virtual evacuations’ which would not be restricted by safety issues. Computer modelling can include algorithms to simulate individual passenger characteristics such as age, mobility, gender and personality which affect their movement within the cabin. Programs can also include physical attributes of the cabin, such as seat pitch, aisle width, exit size and availability, smoke, fire, and other characteristics that influence the passengers’ movements. These simulations can be run multiple times through a number of different accident scenarios in which different emergency exits were available or movement was slowed due to poor visibility, smoke toxic fumes or fire conditions.

Professor Ed Galea from the Fire Safety Engineering Group (FSEG) at the University of Greenwich specialises in modelling human behaviour in evacuation situations. FSEG has developed the EXODUS emergency evacuation software, one variant of which is the airEXODUS simulation for aircraft evacuations which includes such human elements as ‘negative panic’ in which passengers fail to move or ‘exit hesitation’ in which passengers hesitate before jumping onto an emergency slide or the inclusion of people with disabilities. The airEXODUS software include variables for movement, individual behaviour, personal characteristics and atmospheric and physical environment, such as available exits, heat and toxic products in the cabin. In a simulated EXODUS evacuation of a wide-bodied aircraft carrying 112 passengers with a toxic gas environment, there were 41 fatalities, despite an average evacuation time of just 17 seconds. The software has also been used to simulate evacuations from aircraft which do not yet exist, such as a passenger-carrying blended wing body.

However, computer modelling is not currently recognised by the regulatory authorities to demonstrate the evacuation capability of aircraft. Perhaps the best conclusion comes from a final comment from a passenger aboard the Emirates 777. “I think we have lost all other belongings. They would have been completely burnt. But that’s not important. We can always replenish these things. But a life lost can never be replaced.”

12 August 2016