Regulation – Page 2 – John Vincent

Shifting Perspectives

Daily writing prompt

What’s a topic or issue about which you’ve changed your mind?

If you write the perfect rule, you will get the desired outcome. Authoring a specification that is robust and watertight will assure success. Having the best possible plan will deliver the best possible results. All sounds reasonable – doesn’t it? It’s not surprising that someone like me, having been schooled in project management, and working in engineering, would have a rational and systematic approach to problem solving. A proven highly successful way of implementing complex technical projects and delivering successful outcomes.

As an analogy I’ll start with mathematics. Nature is a curious beast. What we lean about complex systems is that what happens is highly dependent upon a start point. The initial conditions. Graduate level mathematics about control systems with feedback show that their behaviour changes a lot with a change of initial conditions. So, it’s reasonable to extend that to a systematic approach to just about anything. It’s often true.

Fail to plan – plan to fail. That idiom is a simple few words to sum up this cause and effect. Used by famous names and often quoted. Management training books are littered with this notion.

20-years ago, my team introduced the first European Aviation Safety Plan[1]. This initiative was built around the idea that to achieve a common objective a plan is the best and quickest way to get there. A roadmap, a pathway, a strategy, call it what you will.

Start by identifying problems and then propose a fix for each one. Not all problems but the ones that fit that awkward Americanism – the low hanging fruit. Namely, the biggest problems (fruit) that can be solved with the least effort (easily picked).

Here’s where I’ve changed your mind. Maybe not changed in a dramatic sense but shifted perspective. It’s essential to have a plan, even if it’s just in my head, but it can be overstated as the most important part of a process of change.

The Plan, Do, Check, and Act (PDCA) cycle, starts with a plan. It must start that way. However, each of the four steps is equally important. Seems obvious to say. Even so, it’s often the case that a press release, or alike, will state – we have a plan, roadmap, pathway, strategy, as if that’s the job done.

Management teams will smile with a sense of achievement and show off their plans. A decade down the line that celebration might seem less momentous as the “do” part of the process turns out to be harder than anticipated.

This basic model for systematic change is a good one. Where I’ve changed my emphasis is in the distribution of effort. Don’t put all available energies into constructing the perfect plan. Yes, the initial conditions are important but they are not everything. The key part of the process is the cycle. Going around it with regularity is a way of delivering continuous improvement. Afterall, when it comes to a subject like aviation safety, that’s what’s needed.

[1] 2005 – DECISION OF THE MANAGEMENT BOARD ADOPTING THE 2006 WORK PROGRAMME OF THE EUROPEAN AVIATION SAFETY AGENCY

Unintended Consequences

There’s a list that must exist somewhere in the bowels of Government which describes the dumbest things that have ever been done. The law of unintended consequences. Where an aim may have been honest, but the reality was a deep dive in embarrassment and failure.

If this list doesn’t exist it dam well should. It’s a sort of lessons learned for civil servants, politicians and think tanks. Don’t propose anything X because the last time someone did that they crashed and burned. Or more subtly it was years later that people cursed the day that such a dumb idea was advanced.

I’m not going to argue against market forces. How could I. From an early age markets were part of my life. That’s local agricultural markets. My father bought and sold livestock. The bread and butter of livestock farming is to buy at one price, add value and then, hopefully, sell at a better price. Markets rise and fall in ways that are often mystical.

The UK imports approximately 46% of the food it consumes. Even that figure is 5 years old. I suspect that food imports have increased in the meantime. That’s in a country that is richly blessed with quality agricultural land. Fine, we (UK) are none too good at growing olives or avocados but the range of produce that it is possible to grow is huge.

Grassland is our greatest asset. Every time I flew back from an overseas trip, just looking down from the aeroplane remined me just how the UK is a carpet of green. Field systems that have ancient origins still dominate the landscape.

Livestock farming has changed radically since my father’s time. Fortunately, we have avoided, in most cases, the levels of intensification and factory methods that others have adopted. Hormone injected beef comes from cattle that live sad lives. People know this and have hands down rejected industrial farming to that level of intensity.

Domestic food production has changed because of Brexit and not for the better. One threat to domestic food production has been some of the ridiculous trade deals that have been struck by this Government and its predecessors. Making it harder for exporters and easier for importers.

Political policy towards the countryside has rightfully taken up the need to restore biodiversity and preserve some of our most precious landscapes. Trouble is that at the same time, little or no thought has been given to the need to support domestic food production. It’s like a policy desert. It’s one thing to talk about food security. It’s another to do anything about it.

With the Labour Government threatening to take large amounts of capital out of UK farming with their inheritance tax plans, they will be making family farming a thing of the past. It’s one of the dumbest things that have ever been done.

There’s general agreement that we shouldn’t encourage wealthy people to use land as a repository for their wealth. However, tax advisors have been telling them to do that for decades. Buy land and pay less tax. Reversing that long standing trend needs an intelligent policy not a crude sledgehammer to crack a nut. Even if it’s impossible to ween Labour politicians off their ideas on inheritance tax, there ought to be a way of doing it without penalising the innocent. Letting off those non-farming interests that politicians were aiming at originally. Dogma makes bad policy. It’s time to reemphasise the place family farming has in food production.

Regulatory Insights

I can’t remember if my teacher was talking about maths or physics. His scholarly advice has stuck with me. When things get complex, they can seem overwhelming. Problems seem insolvable. So, it’s good to take a deep breath, step back and see if it’s possible to reduce the problem to its most basic elements. Do what could be called helicopter behaviour. Try to look at the problem top-down, in its simplest form. Break it into parts to see if each part is more easily comprehended.

Today’s international aviation regulatory structure, for design and production, follows the arrow of time. From birth to death. Every commercial aircraft that there ever was started as a set of ideas, progressed to a prototype and, if successful, entered service to have a life in the air.

This elementary aircraft life cycle is embedded in standards as well as aviation rules. Documents like, ARP4754(), Aerospace Recommended Practice (ARP) Guidelines for Development of Civil Aircraft and Systems are constructed in this manner. There are as many graphs and curves that represent the aircraft life cycle as there are views on the subject, but they all have common themes.

That said, the end-of-life scenarios for aircraft of all kinds is often haphazard. Those like the Douglas DC-3 go on almost without end. Fascinatingly, this week, I read of an Airbus A321neo being scrapped after only 6-years of operations. Parts being more valuable than the aircraft.

Generally, flight-time lives in operational service are getting shorter. The pace of technology is such that advances offer commercial and environmental advantages that cannot be resisted. Operating conditions change, business models change and innovation speeds forward.

My earlier proposition was that our traditional aviation regulatory structure is out of date. Well, the detail is ever evolving – it’s true. Some of the fundamentals remain. The arrow of time, however fast the wheels spin, mixing my metaphors, remains an immobile reality.

In airworthiness terms an aircraft life cycle is divided into two halves. Initial airworthiness and continuing airworthiness. This provides for a gate keeper. A design does not advance into operational service, along the aircraft life cycle, until specified standards have been demonstrated as met. An authority has deemed that acceptable standards are met.

I’m arguing, this part of the aviation regulatory structure is far from out of date. However much there’s talk of so called “self-regulation” by industry it has not come into being for commercial aviation. I think there’s good reason for retaining the role that a capable independent authority plays in the system. A gate keeper is there to ensure that the public interest is served. That means safety, security and environmental considerations are given appropriate priority.

To fulfil these basic objectives there’s a need for oversight. That is the transparency needed to ensure confidence is maintained not just for a day but for the whole aircraft life cycle. And so, the case for both design and production approvals remain solid. The devil being in the detail.

Aviation Regulations Outdated?

Machines, like aircraft started life in craft workshops. Fabric and wood put together by skilful artisans. Experimentation being a key part of early aviation. It’s easy to see that development by touring a museum that I’d recommend a visit. At Patchway in Bristol there’s a corner of what was once a huge factory. In fact, somewhere where I worked in the early 1980s. Aerospace Bristol[1] is a story of heritage. A testament to the thousands who have worked there over decades.

Fabric and wood played part in the early days. The factory at Filton in Bristol started life making trams. An integral part of turn of the century city life. Carriage work brought together skilled workers in wood, metal and fabrics. It was soon recognised that these were just the skills needed for the new and emerging aircraft industry. The Bristol Aeroplane Company (BAC) was born.

It’s war that industrialised aviation. Demonstration of the value of air power led to ever more technical developments. Lots of the lessons of Henry Ford were applied to aircraft production. Factories grew in importance, employing a large workforce.

My time at the Filton site was in a building next to a hanger where the Bristol Bulldog[2] was originally produced. This was a single engine fighter, designed in the 1920s, in-service with the Royal Air Force (RAF).

Right from the start orderly processes and regulatory oversight formed part of aircraft design and production. The management of production quality started as a highly prescriptive process. As aviation grew into a global industry, the risks associated with poor design or faulty production became all too apparent.

In the civil industry, regulatory systems developed to address the control of design and production as two different worlds. Airworthiness, or fitness to fly, depended on having a good design that was produced in a consistent and reliable manner. So, now we have a regulatory framework with two pivotal concepts: DOA (Design Organisation Approval) and POA (Production Organisation Approval). It took about a century to get here. Now, these concepts are codified within EASA Part 21, FAA regulations, and other national aviation authorities’ frameworks.

Here’s my more controversial point. Is this internationally accepted regulatory model, that has evolved, conditioned by circumstances, the right one for the future? Are the airworthiness concepts of DOA and POA out of date?

This is a question that nobody wants to hear. Evolution has proved to be a successful strategy. At least, to date. What I’m wondering is, now the world of traditional factories and large administrative workforces is passing, how will regulation adjust to meet future needs?

Maybe I’ll explore that subject next.

[1] https://aerospacebristol.org/

[2] https://en.wikipedia.org/wiki/Bristol_Bulldog

Data Interpretation

More on that subject of number crunching. I’m not so much concerned about the numerous ways and means to produce reliable statistics as the ethical factors involved in their production.

Two things. One is the importance of saying truth to power and the other the importance of seeing things as they really are rather than how you or I would like them to be.

Starting with the first. If ever it was a hard day to say this but asserting truth is not one of several options, it’s the best option.

Whatever any short-term gains there are in distorting a description of a current situation, in the longer term the truth will out. Now, that may not have always been so. It’s often said that the victors write history. That famous view had some validity when literacy was not universal or when texts were chained in church libraries. Now, information speeds through the INTERNET (and whatever its successor will be). Controlling or supressing information has become like trying to build a castle out of sugar on a rainy day.

The second factor is more troublesome and, for that matter, more difficult. It could be the tug of war between subjectivity and objectivity. What we see is so much dependent upon the observer. What we hear is conditioned by what we’ve heard in the past.

I saw this often in the interpretation of a written narrative. Aviation accidents and incidents are reported. Databases full of multivarious reports of different origins siting there waiting to be read. This is a good thing.

It’s the choice of language that shapes our understanding of past events. That can be voluminous and contradictory. It can be minimalist and ambiguous. It can have peculiar expressions or fuzzy translations. Even if reporters are asked to codify their observations, with a tick box, there remains wide margins.

The writer of a story often knows what they want to say. It might be obvious to them what happened at the time of writing. Then it’s the reader who takes that up. A text could be read years later. Read by many others. Similar stories may exist, all written up differently. Hopefully, slight variations.

Seeing things as they really are, rather than how you would like them to be, without bias, requires more than a degree of care. A great deal of care.

It’s hard enough for an enlightened and skilled analysist to take a sentence and say “yes” I know exactly what happened. Not just what but all six of these – who, what, were, when, how and why. In future, the artificial intelligence tools that get used by authorities will have the same challenge.

For all our technological wonders, it’s the writers of reports that shapes our understanding. From a couple of sentences to a massive dissertation.

Try telling that to a maintenance engineer whose last job of the day, before going home, is to file an occurrence report after a terrible day at work. In a damp hanger with a job only half done. Tomorrow’s troubles looming.

POST: Rt Rev Nick Baines and his Thought for the Day on BBC Radio 4 is thinking the same this morning. Truth is truth. In his case it’s Christian truth that he has in mind. There lies another discussion.

Why 12,500 Pounds?

Regulation is a strange business. It often means drawing lines between A and B. Bit like map making. Those lines on a map that mark out where you are and the features of the landscape. You could say that’s when all our troubles start but it’s been proven unavoidable. As soon as our vocabulary extends to words like “big” and “small” someone somewhere is going to ask for a definition. What do you mean? Explain.

For a while you may be able to get away with saying; well, it’s obvious. That works when it is obvious for all to see. An alpine mountain is bigger than a molehill. When you get to the region where it’s not clear if a large hill is a small mountain, or not then discussion gets interesting. Some say 1000 ft (about 300 m) others say much more. There’s no one universal definition.

[This week, I drove through the Brecon Beacons. Not big mountains but treeless mountains, nevertheless. Fine on a clear day but when it rains that’s a different story. This week Wales looked at its best].

Aviation progressed by both evolution and revolution. Undeniably because of the risks involved it’s a highly regulated sector of activity. Not only that but people are rightly sensitive about objects flying over their heads.

For reasons that I will not go into, I’ve been looking at one of these lines on a regulatory map. One that’s been around for a long time.

I cannot tell you how many discussions about what’s “minor” and what’s “major” that have taken place. That’s in terms of an aircraft modification. However, these terms are well documented. Digging out and crewing over the background material and rationale is not too difficult, if you are deeply interested in the subject.

The subject I’m thinking about is that difference between what is considered in the rules to be a “large” aeroplane and a “small” aeroplane. Or for any American readers – airplane. So, I set off to do some quick research about where the figure of weight limit: maximum take-off weight of 12,500 pounds or less originated for small airplanes (aeroplanes).

I expected someone to comment; that’s obvious. The figure came from this or that historic document and has stuck ever since. It seems to work, most of the time. A confirmation or dismissal that I wanted addressed the question, is the longstanding folklore story is true. That the airplane weight limit was chosen in the early 1950s because it’s half the weight of one of the most popular commercial transport aircraft of that time.

There is no doubt that the Douglas DC-3[1] is an astonishing airplane. It started flying in 1935 and there are versions of it still flying. Rugged and reliable, this elegant metal monoplane is the star of Hollywood movies as well as having been the mainstay of the early air transport system is the US. Celebrations are in order. This year is the 90th anniversary of the Douglas DC-3[2].

What I’ve discovered, so far, is that the simple story may be true. Interestingly the rational for the weight figure has more to do with economic regulation than it has with airplane airworthiness. The early commercial air transport system was highly regulated by the State in matters both economic and safety. Managing competition was a bureaucratic process. Routes needed approval. Thus, a distinction established between what was commercial air transport and what was not.

POST 1: There is no mention of 12,500 pounds in the excellent reference on the early days of civil aviation in the US. Commercial Air Transportation. John H. Frederick PhD. 1947 Revised Edition. Published by Richard D. Irwin Inc. Chicago.

POST 2: The small aircraft definition of 12,500 pounds max certificated take-off weight first appears in US CAB SPECIAL CIVIL AIR REGULATION. Effective February 20, 1952. AUTHORIZATION FOR AIR TAXI OPERATORS TO CONDUCT OPERATIONS UNDER THE PROVISIONS OF PART 42 OF THE CIVIL AIR REGULATIONS. This was a subject of economic regulation in the creation of the air taxi class of operations.

[1] https://airandspace.si.edu/collection-objects/douglas-dc-3/nasm_A19530075000

[2] https://www.eaa.org/airventure/eaa-airventure-news-and-multimedia/eaa-airventure-news/2025-07-17_dc3_society_celebrate_90_years_douglas_dc3_airventure25

Aircraft Safety and Fuel Starvation

Unsafe. In common language it’s the opposite to being safe. So, take a definition of “safe” and reverse it. Let’s say to be safe is to be free from harm (not a good definition). That would lead to “unsafe” being subject to harm or potentially being subject to harm. The probabilistic element always creeps in since it’s the future that is of concern. Absolute safety is as mercurial or unreal as absolute certainty.

Let’s apply this to an aircraft. The ultimate harm is that of a catastrophic event from which there is no escape. Surprisingly, taking a high-level view, there are few of these situations that can occur.

Flying, and continuing to fly, involves four forces. Lift, Weight, Thrust and Drag. It’s that simple. An aircraft moves through the air with these in balance. Flying straight and level, lift opposes weight and thrust opposes drag.

Yes, there are other safety considerations. If there are people on-board. For example, it’s important to maintain a habitable environment. At higher altitudes that requirement can be demanding. Structural integrity is important too. Otherwise flying is a short-lived experience.

In the recent Air India fatal accident, the four forces of flight were not maintained so as to make a continued safe flight possible. The wings provided lift but the force that was deficient was thrust.

Two large powerful engines, either of which could have provided enough thrust, were unable to do so. The trouble being fuel starvation. Fuel starvation occurs when the fuel supply to the engine(s) is interrupted. This can happen even when there is useable fuel on board an aircraft[1].

Sadly, in the records there are numerous aircraft incidents and accidents where this has happened. Quite a few fuel starvation incidents and accidents occur because of fuel mismanagement. This can result from a pilot selecting an incorrect, or empty, fuel tank during a flight.

Now and then, it is the aircraft systems that are at fault. The pilot(s) can be misled by a faulty fuel indication system[2]. In one notable case, a major fuel leak drained the aircraft’s fuel supply[3].

When there is useable fuel on-board an aircraft, the imperative is to restart and recover. It is not uncommon or unreasonable for there to be a delay in restarting engine(s), especially when a fuel starvation event is entirely unexpected. Diagnosis takes time given the numerous potential causes of a starvation event.

In cruise flight there is time available to perform a diagnosis and take appropriate corrective action. Both take-off and landing have their hazards. Both are busy times in the cockpit. When looking at the worldwide safety numbers, less fatal accidents occur on take-off than landing. The numbers Boeing provide put take-off at 6% and landing at 24% of fatal accidents. Each one only occupies about 1% of the total flight time.

Although these are the numbers, my view is that, even though take-offs are optional and landings are mandatory, the requirements for adequate thrust are most critical during take-off. This is arguable and it reminds me that safety assessment is never simple.

[1] https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM

[2] https://asn.flightsafety.org/asndb/322358

[3] https://asn.flightsafety.org/asndb/323244

Understanding Boeing 787 Avionics

In what I’ve written so far, I’ve taken the humancentric view much as most commentators. The focus of interest being on what the two Air India crew members were doing during the critical moments of this tragic flight. Let’s shift perspective. It’s time to take an aircraft level view.

On the Boeing 787-8 “Dreamliner”, the flight deck has two crew seats and two observer seats. One observer seat is directly behind and between the two crew seats. Since these observer seats are not mentioned in the preliminary report, it’s responsible to assume that they were unoccupied.

In my days working on civil aircraft certification, it was often as a part of a multidisciplinary team. I suppose one of the privileges of working on aircraft avionic systems is that they touch every part of a modern civil aircraft. That meant working with highly experienced specialist in every technical field, including flight test pilots and engineers.

When it came to reviewing aircraft system safety assessments, we’d often put it like this, you look at the aircraft from the inside out and well look at the aircraft from the outside in. Meaning that the flight test team looked at how the aircraft flew and performed. Systems engineering specialists focused on how the aircraft functioned. What was the detailed design, the means and mechanisms. It was by putting these differing perspectives together that a comprehensive review of an aircraft could be established.

Here’s where I need to be careful. Although, I worked on the technical standards¹ for complex aircraft systems, I did not work on the Boeing 787 at initial certification.

If I go back 25-years, a major change that was happening with respect to aircraft systems. It was the move to apply Integrated Modular Avionics (IMA). This was a move away from federated systems, where just about every aircraft function had its own box (autopilot, autothrottles, instruments, etc.) There was a fundamental architectural difference between federated and IMA systems.

The Boeing 787 has what is called a Common Core System (CCS). As an analogy let’s think of a time before the smart phone became universal. I had a Nokia mobile phone, a Canon camera, a HP calculator, a Dell lap-top, lots of connectors and pen and paper. Now, the only one that has survived the passage of time is the pen and paper.

So, it is with modern civil aircraft. An Integrated Modular Avionics (IMA) hosts the applications that are necessary for safe flight and landing. The IMA hosts functions that provide, Environmental Control, Electrical, Mechanical, Hydraulic, Auxiliary Power Unit (APU), Cabin Services, Flight Controls, Health Management, Fuel, Payloads, and Propulsion systems.

Information is digitised (sensors, switches and alike), processed and then acted upon. General Processing Modules (GPM) inside the aircraft CCS perform the functions needed. There’s an array of these GPMs and redundancy to provide a high integrity aircraft system.

An aircraft’s Fuel Shutoff Valve Actuator depend on the above working as intended in all foreseeable circumstances. No doubt the accident investigators are undertaking an analysis of the Boeing 787 avionics architecture to gain assurance that it worked as intended.

Standards: EUROCAE started a working group (Number 60) in September 2001, which was tasked to define guidance. Later, in November 2002, there was a merge with an RTCA steering committee (Number 200). ↩︎

Fuel Control Switches

I’ll not go any further than the investigation report that’s in the public domain. The Air India AI171 Boeing 787-800 Preliminary Report is published for all to read. The aircraft’s Enhanced Airborne Flight Recorder (EAFR) has been replayed. Sadly, this report raised questions as much as it closes down erroneous theories.

It warrants saying again, and again. My thoughts are with the friends and families of those affected. They deserve to know exactly what happened and as far as is possible, why. Not only that but the global travelling public need to be confident that any necessary corrective action is being taken to prevent a recurrence of such a rare fatal accident.

What requires a one or two words is one of the commonest ways we interact with electrical and electronic systems. The humble switch. In fact, they are far from humble and come in lots of shapes and sizes. The general idea is that a mechanical device, that can be manipulated with a purpose in mind, is used to control the flow of electrical current. There are non-mechanical switches, but I’ll not go there for the moment.

I remember conversations with my aircraft electrical engineering colleagues. It goes like this – you deal with the small currents (avionic systems), and we will deal with the big ones (power systems). Also, a mantra was that all electrical systems are, in part, mechanical systems. Switches, cables, generators, control valves, relays, bonding, you name it, they are in part, mechanical systems. In the past traditional electrical engineers got a but jittery when faced with “solid state” controls (semiconductors).

Switches. I’ve seen the words “cognitive engagement” used. In simpler terms, by design, pilots interact with switches with a purpose in mind. Equally, as in the world of human factors, unprotected switches can be operated in error, unintentionally or by physical force.

So, what are the chances of two protected Fuel Control Switches moving, within seconds of each other, at the most critical phase of an aircraft’s flight?

[There is a discussion to be had in respect of timing. Remember the record from the flight recorders is a sampling of events. The sampling rate maybe as low as one per second. Note: EASA AMC2 CAT.IDE.A.190.]

These cockpit switches are designed and certificated to perform as intended under specified operating and environmental conditions. That’s a wide range of vibration and temperature (shake and bake).

Switch operation is indicated by their physical position[1]. In addition, operation of these switches will be evident by cockpit indications. The concept being that a flight crew can confirm that the Fuel Control Switches have moved by their effect on the engines. If a crew need to take corrective action it is in relation to the information presented to them by the engine instrument system.

The report makes it clear that both mechanical switches transitioned from ‘RUN’ to ‘CUT-OFF’ almost immediately as the aircraft became airborne. That is a worst-case scenario. The time available to recognise and understand the situation, for training to kick-in, and then to take appropriate corrective action was insufficient.

This leads me to think that there may be a case for disabling the Fuel Control Switch function up until at least an altitude where aircraft recovery is possible. Now, these switches need to be available up until the V1 speed is achieved (Example: aborting a take-off with an engine fire). After that an aircraft is committed to becoming airborne.

I suspect the reason there is no inhibit function is the possibility of adding another potential failure condition. Inadvertent and unrecoverable disabling of ‘CUT-OFF’ are scenarios that would need to be considered. No doubt a reasonableness argument was used. No crew would shut-down both engines down immediately an aircraft became airborne, would they?

POST: I hope I haven’t given the impression that this is a case of simple switches and wires. The Boeing 787 is a digital aircraft. Mechanical fuel technology plays its part but control functions are digital.

[1] Designs that offer switch illumination are not used in this case.

Causal Chains in Accidents

It becomes apparent to me that there’s much commonplace thinking about accidents. What I mean by this is that there’s simple mental models of how events happen that we all share. These simple models are often not all that helpful. Commonplace in that journalists and commentators use them as a default. It’s a way of communicating.

Don’t worry I’m not going on a tirade of how complex the world happens to be, with a dig in the ribs for anyone who tries to oversimplify it. We need simple mental models. Answering questions and explaining as if everything is an academic paper doesn’t help most of us.

I talk of no less than the causal chain. That’s a love of putting the details of events into a chronological sequence. For an aviation accident it might go like this – fuel gets contaminated, fuel is loaded onto aircraft, engine stops, pilot makes an emergency landing, aircraft ends up in a field and an investigation starts. The headline is dominated by the scariest part of the sequence of events. Key words like “emergency” are going to command the readers attention.

In my example above it’s reasonable to assume that there’s a relationship between each link in the chain. The sequence seems obvious. It’s easy to assume that’s the way the situation developed and thus made the accident or incident. However, it doesn’t have to be so. Let’s say there was contaminated fuel but not sufficient to stop an engine. Let’s say for entirely unrelated reasons (past events) the spluttering of the engine led the pilot to think that there was a fire on-board. Fuel was shut down. Thus, events took a different sequence.

Anyway, my point is an ancient maximum. Question what you first hear (or see). The recent tragic fatal accident in India is an example of much speculation often based on a proposed orderly sequence of events. Many commentators have lined them up as, this happened, and then that happened and then something else happened. QED.

What I’ve learned from reading and analysing accident reports over the years is that such major accidents are rarely, if ever, a simple sequence or only a couple of factors combined.

Yes, adding circumstantial factors to a causal chain adds realism. Even that is not so easy given that each factor has a different potential influence on the outcome. Atypical circumstantial factors are time of day or night, weather, atmosphere conditions and the human and organisational cultural ones.

To make sense of the need to put events in an order a more sophisticated model is the fishbone diagram[1]. The basic theme is the same. A core causal chain. What’s better is the injection of multiple factors to make a more authentic accident model.

Although, we do think in a cause-and-effect way about the world, if there are more than 4 or 5 factors combined in a random manner these models are far from authentic. My message is not so sophisticated, beware of simple sequences as being definitive.

[1] https://asq.org/quality-resources/fishbone