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Scientists comment on a London-bound Boeing 787-8 aircraft crashing shortly after take-off in India.
Dr Guy Gratton, Associate Professor of Aviation and the Environment, Cranfield University, said:
How rare is it for there to be a single survivor in a plane crash such as the Air India one and/or any plane crash in general?
“It’s very unusual. Modern airliners are designed to be crashworthy, which is to say they’re designed to provide the best possible chances of passengers and crew surviving any accident. The result of that is that most or all, or most of the passengers and crew survive, or that the impact was so high-energy that nobody survived. So this case of a single lucky survivor is rather unique.
What are the odds of there being only one survivor in a plane crash? How probable is it?
“Hard to put numbers on it, but very unusual, as I’ve described above.
The survivor of the Air India plane crash was in Seat 11A – was there anything about this seat that may have increased the odds of survival for this passenger?
“Yes, it was forward of the wings (where all the fuel is) and next to an emergency exit. So, I think that these probably led to the seat and/or some immediate structure around it being thrown clear of the main wreckage and the fuel explosion.
Are there any seats on a plane that come with a higher chance of survival during a plane crash than other seats? If so, how so/why?
“No, not really. It will all depend somewhat upon the nature and trajectory of the accident.
What may have been the biggest factors that helped this passenger survive the Air India plane crash?
“We just don’t know yet, but the issues of accident survivability will definitely be a major area of interest in the coming report. It’s worth remarking here that the most important part of air accident investigation reports is the recommendations, and those will be focussed on either preventing future accidents, or upon making any future accidents as survivable as possible. So the recommendations from the investigation, may well say some very significant things in this regard.
How do the electronic/power systems of a Dreamliner plane work? Are there any interconnected systems meaning that if something fails it could cause a knock on effect (i.e. an engine failure)?
“The power systems of the B787 are complex with a lot of duplication. Each engine has two generators, plus there are two “Auxiliary Power Units” which provide an additional emergency source of power, plus in flight when everything else has failed a “Ram Air Turbine” can extend under the rear fuselage to provide an additional source of electrical and hydraulic power, essentially a small high speed windmill. So even if both engines fail there should be power to the flight controls and cockpit electronics (which we call avionics). However, clearly if both engines fail, we still have the fundamental problem that there’s no thrust to keep the aeroplane flying. There is evidence suggesting that the RAT had deployed, and there’s no evidence at the moment suggesting a control systems or avionics failure prior to the crash.
The survivor reports witnessing green and white flickering lights during the crash, what could these have been and what could they have indicated?
“They *might* indicate that the power systems were switching from primary to backups, but I am conjecting here and don’t regard this statement as authoritative.
How would you expect the Aircraft Accident Investigation Bureau (AAIB)will carry out the investigation of the crash?
“AAIB India (the Aircraft Investigation Bureau) will be leading this, supported certainly by the American NTSB, the British AAIB (Air Accidents Investigation Branch), and teams from Boeing and General Electric. I’d expect them in the first instance to be collating and documenting wreckage, the two onboard recorders (the CVR or Cockpit Voice Recorder, and the FDR or Flight Data Recorder), and any external evidence, eyewitness accounts and so-on. They’ll also be securing the aeroplane’s maintenance records. Their initial task is to analyse all of this very large amount of data with a view to understanding the overall sequence of events, and all and any causal factors. This will take quite some time, but there is a likelihood of their producing interim reports given the massive public interest in the accident. Eventually I would expect a very thorough report, of which the most important component will be the last part – the recommendations aimed at preventing, or ameliorating, any future accidents.”
Prof Graham Braithwaite, Director of Aerospace and Aviation, Cranfield University, said:
How rare is it for there to be a single survivor in a plane crash such as the Air India one and/or any plane crash in general?
“Very rare – partly because aircraft accidents are very rare and partly because the majority of aircraft accidents are survivable. There have been cases in the past of one or a very small number of survivors in very serious accidents.
What are the odds of there being only one survivor in a plane crash? How probable is it?
“It is impossible to say, partly because that depends on which aircraft types you include and whether you include non-fatal accidents and incidents.
The survivor of the Air India plane crash was in Seat 11A – was there anything about this seat that may have increased the odds of survival for this passenger?
“Without evidence from the accident site, then this would be pure conjecture. Even when investigators examine the scene, they may not be able to answer that question as it will have changed as a result of the fire and rescue efforts. The survivor describes the doors have gone and that he crawl through a gap in the fuselage onto the first floor of a building – so it could even be that the thing that made all the difference was where it was relative to the wrecked building.
Are there any seats on a plane that come with a higher chance of survival during a plane crash than other seats? If so, how so/why?
“It’s such a hard question to answer.
“While it is of no consolation to those affected by the tragic accident which has occurred yesterday, the simple answer is that all seats on modern jet aircraft are incredibly safe. The accident record proves that, especially compared to other modes of transport like driving.
“Many things go into designing aircraft, airspace, airports, procedures and training. International standards and recommended practices shared through organisations like ICAO (international civil aviation organisation – a part of the UN) and the International Air Transport Association (IATA) have helped to reduce the likelihood of an aircraft being involved in an accident, and also increase the likelihood of survival.
“The design of the seat and even the fixtures around them must meet strict crashworthiness standards as well as flammability standards. The space around exits and the distance between a seat and an exit is also tightly controlled. We shouldn’t forget the role of the cabin crew too – essential in an emergency where we know their commands can make all the difference.
“Passengers can contribute to their own safety by listening to the safety briefing at the start of a flight reading the safety card and, in an evacuation, leaving their luggage behind. The cabin crew’s primary role is safety and they deserve to be respected when they give their briefing and ask people to stow luggage carefully or remove headphones. We know from passenger survival work conducted at Cranfield and Greenwich Universities that following the cabin crew’s instructions makes a huge difference.
“While scenes from yesterday’s accident made it look like no-one could survive, this is not a typical accident. The majority of aircraft accidents are survivable. This is partly because every time an accident happens, we take the time to investigate – not to apportion blame or liability but to learn lessons to prevent recurrence. This is cultural and something that continues to keep aviation safe.
What may have been the biggest factors that helped this passenger survive the Air India plane crash?
“On this occasion, while the design of the aircraft may have helped including the seatbelt, it may have been pure chance that dictated why it was him and not someone else.
How do the electronic systems of a Dreamliner plane work? Are there any interconnected electronic/power systems meaning that if something fails it could cause a knock on effect (i.e. an engine failure)?
Aircraft are designed to have multiple redundant systems – in other words, if a critical failure were to occur, then there is at least one if not two independent back-ups. This is how we achieve such a high level of engineering reliability and why an aircraft of this size could still fly on only one engine or with a failed hydraulic system.
In this case, the aircraft was at a critical stage of the flight as it continues to accelerate and climb away. While aircraft are designed to withstand an engine failure during take-off and the crew will have trained for it many times in the simulator, there have been very, very rare occasions where to engines have failed (such as with the A320 which ended up in Hudson River). While investigator will be looking in detail at what may have happened to the engines, they will also be looking at the parts of the aircraft that help to generate lift on take-off (flaps and slats) to see whether they functioned as expected. Until there is hard evidence such as from the flight data recorder, we don’t know what caused the aircraft to sink.
The survivor reports witnessing green and white flickering lights during the crash, what could these have been and what could they have indicated?
“I am really not sure. It could have been a warning from the flight deck to the cabin crew, but there are other explanations. For someone who has been through as traumatic an experience as the survivor has, while their witness testimony is really important, it would need checking. We know that recollections can be faulty or affected by what someone experienced. Our memory of timescales also can be affected.”
How would you expect the Aircraft Accident Investigation Bureau (AAIB)will carry out the investigation of the crash?
“The investigation will be led by the Indian Aircraft Accident Investigation Bureau under a set of international standards known as “ICAO Annex 13”. ICAO is the International Civil Aviation Organisation and is the bit of the UN where 193 member states agree on international standards and recommended practices for aviation. The investigation is NOT to allocate blame or liability ( that could come as a separate judicial inquiry), but rather to find opportunities to prevent future accidents. Annex 13 provides for other states to be involved – in this case the US National Transportation Safety Board (NTSB) because they represent the “State of Manufacture” and the UK because of the large number of people on board. Others may offer assistance with things like reading out data recorders.
“It is likely that international investigators were dispatched yesterday to help with evidence gathering. They will be looking at wreckage on the scene, the accident recorders and also interviewing witnesses and collecting picture and videos including CCTV from near the scene. At this stage it is about making sure they don’t lose evidence e.g. from the site during recovery efforts, or from the hangar, airport or training records. Witness testimony also risks changing as people talk to others and see things (such as photos or video) they didn’t see on the day. The multinational, multidisciplinary team will work together and can also involve specialists from the manufacturer or operator… but under very strict controls to ensure the independence of the investigation.
“The CVR and FDR will tell us a lot – assuming they are undamaged, but they tend to explain ‘what’ happened rather than ‘why’. Knowing what they say may at least help us to rule some theories out which will help the industry know how best to react in the short term. While the final report will take many months (and even years), if there are urgent safety concerns or lessons, they tend to be shared across the industry swiftly.”
Prof Paul Fromme, Chair of the Aerospace Division, Institution of Mechanical Engineers, said:
How engineering expertise will be used in the response and in the investigation to figure out what’s happened. What are the next steps in the investigation from an engineering perspective?
“The first step will be to recover and analyse the flight data and cockpit voice recorders (‘black box’). While it obviously was a catastrophic crash, it occurred in an accessible area and from low altitude, therefore there is a good likelihood that these will be retrieved soon and in reasonably good condition to facilitate a quick initial analysis. These will be evaluated by the Indian Aircraft Accident Investigation Bureau, with possible assistance from Boeing and US authorities. In addition to the voice record of any cockpit conversations, the flight data recorder has the information on engine and control settings. This should show quickly if there was a loss of engine power or lift after take-off and allow a preliminary determination of the likely cause for the crash.”
Dr Akhil Bhardwaj, Senior Lecturer and Researcher in Aviation Safety, University of Bath, said:
“The Dreamliner planes have an excellent track record for safety. However, one should be aware of the aeroplane’s history. It was only last year that whistleblower and quality engineer Sam Salehpour drew attention to assembly problems concerning Dreamliners during his senate hearing in April 2024 [1,2]. The Dreamliner has also had issues with batteries catching fire in 2013, which was subsequently investigated by the National Transportation Safety Board [3,4,5]. With regards to the Air India tragedy, it is too early to say what might have happened but it reminds us that safety requires constant vigilance.”
References:
1 – https://www.hsgac.senate.gov/wp-content/uploads/Salehpour-Testimony-24.04.17.pdf
3 – https://i2.cdn.turner.com/cnn/2014/images/12/10/air1401.pdf
4 – https://edition.cnn.com/travel/article/boeing-787-dreamliner-investigation-report
5 – https://www.aljazeera.com/economy/2014/9/10/boeings-787-battery-problems-from-the-start
Dr James Campbell, Reader in Structural Integrity, Brunel’s University of London, said:
“Fortunately it is unusual for a commercial passenger plane to crash at all. The take-off and approach and the landing phases of flight do represent a higher risk if a problem occurs, as the flight crew may have very little time because of the altitude to understand and manage the issue they are dealing with.
“I have seen no information relevant to the causes of the crash and it is anyway too early to speculate. The crash investigation will have access to records of the flight, the flight recorders and other information to investigate why the crash occurred. 787’s are modern and safe aircraft – I am not aware of any relevant issues with the safety record of the 787.”
Dr Simon Bennett, Director of the Civil Safety and Security Unit, University of Leicester, said:
“We are all saddened to learn about the loss of Air India Flight 171 shortly after departing Ahmedabad for London Gatwick. It is being reported that all but one passenger survived on board and several people on the ground were killed or injured”
“It is noted that there is already much speculation as to the cause of the accident. While the clamour to understand why the aircraft crashed is understandable, people should resist the urge to speculate, first, because it is disrespectful to the relatives and friends of the deceased, and secondly, because speculation may prejudice the official investigation, which will be led by India’s Aircraft Accident Investigation Bureau and supported by Boeing, the accident airplane’s manufacturer.
“The reason that formal investigations into aircraft accidents take anything up to two years is that, often, an accident is the result of multiple failures – technological and human.
“Identifying every failure such that the chances of a repeat are kept to an absolute minimum takes a significant amount of time and effort.”
Dr Jonny Williams, Researcher in Climate Impacts on Aviation, University of Reading, said:
“It is standard procedure for airlines to balance the payload on all flights, to take into account the length and angle of runways, and atmospheric conditions. This includes the weight of passengers and crew, baggage, freight and aviation fuel. It’s one of the reasons why airlines weigh your bags that go into the hold and operate limits on cabin baggage size.
“The runway at Ahmedabad is 3.5km, and airport runways are designed to have additional length to allow extra space for take-offs and landings to occur safely. If there is any danger that an aircraft can’t take off, due to load or atmospheric conditions, then they are not allowed to fly.
“Hot weather does increase the take-off distance required and therefore the amount of runway needed for take-off, and these calculations are considered as standard on every flight. The current temperature in Ahmedabad, of around 39 degrees C, is about average for this time of year in that region. Air India is a major international airline with a strong safety record and long experience of operating in these conditions.”
Richard Gordon, Director of the Disaster Management Centre, Bournemouth University, said:
“Any air accident is a tragedy. Decades of engineering excellence, and billions in investment, have sought to make air accidents rare events. Nevertheless, when air accidents occur, the focus of journalists must rightly change at the outset from discussion regarding the airworthiness of the ‘plane’ to addressing the needs of the ‘people’ affected. These will include passengers and crew, their families and friends, and supporting services that need to function quickly and effectively. How effective are the processes that are caring for the passengers, crew, their families and loved ones?
“Families and members of the public are asking: Who was on the plane? When will the passenger manifest be released? Where do I go for information?
“Airlines recognise the importance of providing a central point of contact and at the time of writing it is noted that Air India has already implemented their ‘dark site’. (This is a copy of their usual web site but with a more sombre look, as a mark of respect of families who are using the link to ask questions or provide information. It is noted that Air India launched this site quickly),
“In addition, a dedicated telephone number should be released to the public, by the affected airline, so that anyone thinking that a member of their family has been involved in the incident can get in contact. In the UK this is often referred to as the ‘Casualty Tracking’ number even though it is intended to reach out to families and friends of both the injured and the uninjured. Since the aircraft came down outside of the airport premises, the police will have cordoned off the immediate area to allow the emergency services to respond, making the scene safe, whilst evacuating and caring for the passengers and crew. We have yet to hear who has survived and who has not.
“Family Assistance Centres should be set up at the airport for relatives and friends to seek information about their loved ones, receive up to date information and confirm details about the passengers. Embassies representing the countries of the passengers and crew will wish to establish information desks at the airport to capture information on behalf of their governments and to provide a focus for affected families.
“Both the airport and the airline will have established a crisis management centre. How quickly are they able to track where everyone is (which hospital have they been taken to?) and provide updates to affected families of both passengers and crew.
“This is inevitably a time of media scrutiny, involving regular interviews with senior leadership teams representatives including the CEO of the Airline, the Minister of Aviation and the Director of the Airport Response. An investigation will take place, in time, to address questions such as ‘what was the cause of this tragedy, who is to blame, and how can we prevent this from happening again?’.
“The purpose of this piece is to focus right now on people and not the plane. Scrutiny should be restricted therefore to how quickly and effectively the passenger manifest was confirmed and released, a family assistance centre established, and a public telephone number released (and integrated with any additional tracking telephone number that the police may have established), so that families can be informed about their loved ones.”
Dr Jason Knight, Senior Lecturer in Fluid Mechanics, University of Portsmouth, said:
“It is very unlikely that the plane was overweight or carrying too much fuel. The aircraft is designed to be able to fly on 1 engine, so the most likely cause of the crash is a double engine failure. Because the altitude was so low, the pilot would have had very little time to do an emergency landing. The most likely cause of a double engine failure is a bird strike which would take out the engine.”
Dr David Birch, Associate Professor of Aerospace Engineering at the University of Surrey, said:
“Given the lack of publicly available information at this early stage, it would not be prudent to speculate what went wrong in this case. However, most air incidents happen around take-off and landing.”
Prof Paul Williams, Professor of Atmospheric Science, University of Reading, said:
“At the time of the departure, the weather conditions at the airport appear to have been very good. It was a dry and sunny day in Ahmedabad, with temperatures near 40°C. There was good visibility and light winds from the west. There was no bad weather in the vicinity.
“There is no indication at this stage that turbulence or other weather conditions were a factor in the crash.”
Prof John McDermid, Director of the Centre for Assuring Autonomy (CfAA), University of York, said:
“It is too early to say much about the cause of the crash in any detail – about the only observation one can make is about the timing. Take-off and landing are the most dangerous phases of flight – accidents from cruise are very unusual. However, that said, it’s surprising that the accident occurred before the aircraft had even got to 200metres altitude. Pilots can abort take-off until quite late in the take-off roll, so it seems like the problem occurred very suddenly in the final part of the take-off roll, or shortly after take-off, and was sufficiently serious to be unmanageable. Given the levels of redundancy in systems, the fact that aircraft are designed to climb out on only one engine, etc. on initial sight this seems a very surprising accident
“Based on data from the aviation safety network [1], it seems this was the first fatal accident of the aircraft type.
“It is very unlikely the plane was overweight or carrying too much fuel – there are careful checks on this.”
1 – https://asn.flightsafety.org/asndb/type/_B787
Prof Graham Braithwaite, Director of Aerospace and Aviation, Cranfield University, said:
What do we know about the situation so far?
“The aircraft involved is an 11-year-old Boeing 787-8 Dreamliner. This is the first major accident involving the 787.
“At this point we don’t know whether there are any survivors or whether there have been any casualties on the ground.
What don’t we know and are waiting to find out?
“At this stage the focus will be on search and rescue at the site. For the airline, they will be focused on caring for family members and friends at both the departure airport and destination. Until the manifest is confirmed, they will be dealing with a very high number of enquiries from concerned friends and families. Early information about the accident is unlikely to be accurate so even though people will look at tools like FlightRadar 24, it won’t tell us anything about the “why it happened”. We should be very careful not to speculate on cause when there is so little reliable information available.
Is it unusual for a plane crash to occur so soon after take-off?
“Yes. Although take off is a critical stage of flight, aircraft accidents are incredibly rare, especially involving modern aircraft types such as the Boeing 787. Take off is a critical stage because the aircraft is still accelerating and any problem-solving requires a rapid response.
Any other information you think is relevant for journalists to know.
“The accident will be investigated by the Indian Aircraft Accident Investigation Bureau – an organisation which is independent from the aviation regulator, and which is focused on ‘not for blame’ safety investigations. This is governed by an international standard known as ICAO Annex 13. Under that, participants will include the US National Transportation Safety Board as the State of Manufacturer. Stated with a significant number of people on board will also have a right to participate so I would expect the UK Air Accidents Investigation Branch to be involved.”
Declared interests
Dr Simon Bennett: No COIs
Prof Paul Williams: No conflicts
Prof John McDermid: No COIs
Richard Gordon: No COIs
For all other experts, no reply to our request for DOIs was received.