Category: Flying

From Prescription to Performance-Based Regulation

One regulatory development that has stuck since the start of the new century is the idea that we need to transition from prescriptive requirements to performance-based requirements. It’s not too hard to understand where the motivation to change has come from but there are several strands to the path. Here’s three that come to mind.

For one, the intense dislike of overbearing governmental regulators who adopt an almost parental attitude towards industry. It’s true that safety regulatory bodies have a duty to serve the public interest. The difficulty arises in interpreting that brief. Not as police officers sometimes did, imagining everyone as a potential miscreant.

My experience as a regulator started at a time when traditional institutional approach was quite common. There was a respectful distance between the airworthiness surveyor or operations inspector and the aviation industry that they oversaw. I think, even the term “surveyor” was one inherited from the insurance industry at the birth of flying.

A wave of liberalisation swept into the 1980s. It was an anathema to those who started their careers as men from the Ministry. The idea that regulators should be in a partnership with industry to meet common goals was not easily accepted. Undoubtably a change was necessary and, naturally, easier for an up-and-coming generation.

The next move away from regulatory prescription came as its value declined. That is, not that there will not always be an element of prescription by matter of the written law. However, for detailed technical considerations it became less and less practical to say, this is the way it must be. The minute decision-makers were faced with the complexity of a microprocessor it become clear that it’s not effective to simply prescribe solutions.

Much of the changes that took place can be traced to the evolution of system safety assessment and the use of probabilistic methods in aviation. In mechanics, prescribing a safety guard for a chain drive is straightforward. For complex electronics saying when a flight system is safe enough requires a different approach. Regulators are now driven to set objective rather than dictate solutions.

My third point is a future looking one. Whatever the history and heritage of aeronautical innovation, it’s true that a “conservative” but rapid adoption of new technology continues to be a source of success. Great safety success as well as commercial success.

Hidden amongst the successes are products, and ways of working that don’t meet the grade. The joke goes something like this: “How can I make a fortune in aviation?” Answer: “Just start with a big one.” Implicit in this observation is a wiliness to innovate at risk. That means, amongst many things, having confidence, adaptability and not be so constrained as to be assured failure. An objective or performance-based approach to safety regulation opens opportunity to innovate more freely whilst still protecting the public interest in safety.

There’s no fixed destination for regulatory development.

1985 to 2025 Trends

On reading J. C. Chaplin’s paper on the first 100-years of aviation safety regulation in the UK[1], it struck me that the journey from the 1910s to the 2010s was one of constant change. That change has not slowed down. In fact, the last 40-years of my aviation career have seen dramatic technological changes that have demanded ever new regulatory methods and practices.  

Overwhelmingly aviation history writings obsess about the early days of flying or the start of the jet age. It’s as if those periods were so dominated by great pioneers that nothing worthy has happened since. I exaggerate for effect, but I think you get the meaning of my comment.

So, what of the race from the 1985 to the 2025? I think that is useful period to look at. One of the reasons is that those years are mark the transition from an analogue era to a digital one.

The early 1980s saw experimentation with the potential for digital technologies, most particularly fly-by-wire systems. Quickly the military understood the increase in aircraft performance that could be gained by use of such technologies. Groundbreaking was Concorde in that it demonstrated that critical electronic control systems could safely go into everyday operation. That project drove the development of new regulatory methods and practices. 

A turning point occurred in the mid-1980s. That silicon revolution that impacted so much of life was dramatically put to use in civil aviation. Computing power had so miniaturised and become affordable so that past theoretical possibilities could now be practically realised.

The Airbus A320 aircraft first flew in 1987. It was a shaky start. Not everyone was convinced that safety critical systems were indeed safe. The not so obvious discovery that the human factor was even more important for a computerised aircraft. Learning to adapt and adjust ways of operating didn’t happen overnight.

The lesson is that learning lessons must be part of the process. Through applying continuous improvement, the Airbus A320 family has grown ever since.

Maybe there needs to be a short paper to cover civil aviation safety regulation from 1985 to 2025. It’s needed now. It’s needed because the next 40-years are going to see equally dramatic changes. In the time to come the main driver will be the environment.

[1] https://www.aerosociety.com/media/4858/safety-regulation-the-first-100-years.pdf

The Revolutionary Role of Hydrogen

Hydrogen has a history with aviation. What could be better. A gas that is so light. So easily produced and with no need heat it up. With a lightweight gas-tight bag and a fair amount of rope, balloon construction took-off. Literally. The proof that hydrogen gas could lift a balloon goes back to the 1780s in France.

Sadly, the downside of this gaseous element is its propensity to combine with other elements. In fact, where would we be without liquid water. On this planet, that most basic and prolific combination of hydrogen and oxygen. Not so much sadly but more luckily.

Step forward about 250 years and we have a different vision for hydrogen in aviation. If it’s combined with the oxygen in the air that we breath, we get nothing more noxious than water. Since, the other forms of combustion, that populate our everyday lives, is distinctly noxious, surely hydrogen has a lot to offer. Talk about downsides. Burning fossil fuels is distinctly unsustainable. Polluting the atmosphere.

This week, I was looking out to sea. At the English Channel (No name changes there, I see). Standing on the pebble beach at Budleigh Salterton. They ought to have an award just for that name. It’s a small seaside town in Devon. The towns cliffs are part of a World Heritage Site, namely The Jurassic Coast[1]. 

Forget the 250 years of humans flying, cited above. About 185 million years of the Earth’s history is for all to see on the Devon and Dorset coast. When we say “fossil fuels” what we mean is that we are living off the back of Earth’s history. Society powers modern life on dinosaur juice. Well, not exactly but plant and animal life from hundreds of millions of years ago. How crazy is that?

Hydrogen, on the other hand, is one of the most abundant elements. It’s everywhere.

Modern day dinosaurs (politicians and pundits) insist that we continue to exploit dinosaur juice until it’s all gone. That’s putting aside any concerns about returning all that carbon to the Earth’s atmosphere. Carbon accumulated over millions of years.

Hydrogen can be a clean fuel. The problem is that saying that and then doing it are two different things. There are complexities that come with using Hydrogen as a fuel. It might be reasonably easy to produce, in multiple different ways, but it’s not so easy to transport.

Producing leak proof systems for transport and storage requires innovative thinking. We can’t just treat it with the familiarity of conventional fuels. Whole new regimes are going to be needed to get Hydrogen from where it’s produced to where it’s needed.

Producing leak proof systems for aircraft is a challenge. Given the odourless and invisible nature of this light gas, accurate and extensive detection systems are going to be needed. If the gas is to be consumed by fuel cells to produce electricity, then there’s going to be a constant struggle against complexity and significant expenditures.

What is reassuring is that none of the above is insolvable. At this time in history, we have the materials technology and control systems that make Hydrogen a viable clean fuel.

[1] https://jurassiccoast.org/

Understanding Aviation Safety

The recent dramatic events in Toronto brought to mind the equally dramatic event of Air France Flight 358 back at the latter half of 2005. Then a large aircraft was destroyed but the crew and passengers got away without fatalities. The combination of bad weather and poor decision-making led to a catastrophic runway excursion.

I remember that the year 2005 shook the aviation community. There was a whole succession of fatal aircraft accidents across the globe. In Europe, Helios Airways Flight 522 was particularly tragic. Errors led to the crew suffering hypoxia and as a result the aircraft and everyone onboard was lost. In Italy, lives were lost as an ATR72 aircraft ran out of fuel and plunged into the Mediterranean Sea near Palermo.

West Caribbean Airways Flight 708 fell from the sky killing all on-board. Kam Air Flight 904 hit a mountain killing all on-board. In Indonesian, Mandala Airlines Flight 091 crashed. A few passengers survived but many people were killed on the ground.

I sincerely hope that 2025 is not going to turn into another 2005. However, I do take the view that there is a cyclic element to the occurrence of fatal accidents. We are often proud to be able to say that the time (number of years) between one cluster of aviation accidents and another grows as overall safety improves but we are a long way from zero-accidents.

The global aviation industry is an incredibly safe industry when considering how many passengers are carried every year. However, zero-accidents remain an illusion however it might be touted as the ultimate goal.

As safety practitioners try to be ever more pro-active in our safety regimes there’s inevitably a reactive element to aviation safety. The aftermath of the 2005 experiences led to ICAO holding its first high-level safety conference in 2010 in Montréal. There have been two more such conferences since. One in 2015 and one in 2011.

The results have been to push the aviation industry towards a more pro-active management of safety. It’s not just the industry. In cases, the regulatory weaknesses that exist in individual States has needed to be given attention.

Add all this up over the last 20-years and you would expect everyone to be pro-actively managing aviation safety. Sadly, that’s not the case as some States and organisations are still managing the transition to a more pro-active approach. Some are so resource constrained that they are more inclined to talk about aviation safety than to act upon it.

Regulatory weaknesses exist in some unlikely places. Additionally, with the fashion of the time being to cut “red tape” at every opportunity, more troubles might be just over the horizon.

I’d like to see a break between the association of what is regulatory and what is considered bureaucracy. The two are not necessarily the same. Regulation and standards are synonymous. And what we know is that there is no successful complex industry without standards.

Please let’s not wait for the next accident report to tell us what to do.

The Evolution of Air Traffic Control

Until civil air traffic started to grow the need for its control wasn’t the number one consideration. The pilot was the master of the skies. A basic “see and avoid” approach was taken. See another aircraft and avoid it at all costs. Note, I am talking about the early 1920s.

If you want a nice exploration of how it all started keep an eye on the site of the Croydon Airport Visitor Centre[1]. The first London airport was not Heathrow or Gatwick. No, there’s a stretch of grass, a hotel, industrial units and out of town shopping standing on the site in Croydon of the first London airport. 

Firstly, we can thank Marconi for the first radiotelephony. Providing a means for pilots to speak to airports enabled the development of Air Traffic Control (ATC)[2]. It got going out of necessity because there was limited space on the ground and many aircraft wanted to take-off and land.

Aerial navigation took off in the 1920s. A hundred years ago. WWII drove advancement in every aspect of technology. After WWII, the basic having been established, an international body was established to set standards for international flying. That’s where today’s ICAO originated.

Radar and VHF radio transmissions were the cutting-edge technology that enabled air traffic to grow. Radio navigation aids developed as did automatic landing systems. So, by the time the jet-age started there was a whole selection of technology available to manage air traffic. Not only that but the standards required for these systems to interoperate around the globe were put down on paper.

That legacy has served aviation remarkably well. Incremental changes have been made as new capabilities have been developed. Most notable of that evolution is to return elements of control to the cockpit. A traffic alert and collision avoidance system (TCAS) does just that. It provides a safety net.

What we have available to manage dense airspace and busy airports is a complex, highly interconnected, interdependent set of systems of systems and procedures that is not easy to unravel. Each part, in each phase of flight, plays its role in assuring safe operations.

News and rumours are that quick fixes are being demanded in the US. Responding to recent accidents and a perception that all the above in antiquated, a well know tech guru has been thrown at the “problem”. I shouldn’t be a cynic, as having a fresh pair of eyes looking at the next steps in the development of air traffic management should be good – shouldn’t it?

It’s my observation, as an engineer who knows a thing or two about these things, is that any simple solution means that the parties have not thought long enough about the problem. In this case there are no quick fixes. However, there’s likely to be incremental improvements and they will not come cheap. 

[1] https://www.historiccroydonairport.org.uk/opening-hours/

[2] https://www.historiccroydonairport.org.uk/interesting-topics/air-traffic-control/

Challenges Facing Supersonic Flight

Congratulations go to “Boom” for their supersonic jet flight[1]. Civil aerospace hasn’t ventured into this space for some time. Breaking the sound barrier is not an everyday occurrence in the civil world. There may be an international market for such new aircraft as much as there’s a market for fast cars and expensive boats.

However, I do not think a supersonic flight is the future of civil aerospace. It’s not mainstream. The environmental objectives for the future of aviation are ambitious. Generally, that means getting people from A to B in as clean and efficient a manner as is feasible. That does not include going ever faster and faster.

This new aircraft type is likely to be solely made in America. So, it does fit with the current political direction of the administration in the US. A triumph of technology. President Trump’s instinct to get rid of rules and regulations may work in the favour of Boom. However, in the end, the deciding factor will be – will the international marketplace want such a new aircraft type?

I certainly recall amazing ambition of the people who brought us the Eclipse aircraft[2]. Small light jets were going to be everywhere. Like a Silicon Valley revolution for the aerospace industries. That didn’t happen as predicted because the economics didn’t stack up. I don’t recall rules and regulations being the problem.

Even so, BOOM technology will have a hard job meeting international safety and environmental standards. I seem to remember that’s not new for supersonic flight. Even if the advancements made improve noise performance, there’s emissions and contrails to ponder.

There is another consideration too. It’s the problem Advanced Air Mobility (AAM) is facing now. To capitalise on their capabilities, these aircraft technologies require the reorganisation (modernisation) of national airspace. Plus, agreement at international level[3].

Supersonic flight over the world’s oceans may get agreement. Supersonic flight over national territory is a much harder sell. Some fliers may pay to slashing their travel times on-route. Going round and round in a stack, waiting to land, with conventional aircraft all around, will soon dispel any excitement.

Good luck to Boom. If civil use is minimal, no doubt defence applications will be numerous.

[1] https://boomsupersonic.com/

[2] https://www.eclipse.aero/about/

[3] https://www.icao.int/environmental-protection/Pages/default.aspx

About Animals and Flying

Pigs do fly[1]. But only the more privileged ones. Yes, animals that fly are not restricted to those with their own wings. It’s true that the animal kingdom has been showing us how to fly long before powered flight took-off. Nothing more graceful than a bird of pray swooping and diving. We (humans) can’t match much of what they do with our flying machines however hard we try.

Birds long inspired great thinkers. They opened the prospect of human flight. If they can do it – why can’t we? Surely the right combination of aerodynamic structures and a source of power would solve the problem. Shocking, in a way, that it wasn’t until a couple of keen bicycle repair men and a smart mechanic persisted until they had a working machine. That was only just over a hundred years back.

So, today’s novelty News item[2] of a cat that didn’t want to leave an aircraft puts a smile on my morning face. For all the farm cats I have known, the story doesn’t surprise me at all. It’s the sort of situation where humans are almost powerless in the face of the preferences of a feline.

Naturally, the engineering staff of an airline will have a good look at where the cat has been in its wanderings. There’s always the remote chance for a rogue moggy to play with something they shouldn’t ought to play with. Even on a modern Boeing 737.

I used the word “remote” but there are definite cases of loose animals causing air safety hazards. Looking this one up, because it sits vaguely in my memory, I do recall a dog that crewed through electrical cables after it got free in a cargo hold. Now, however lovable and cuddly a dog maybe that’s a place that no one wants to be in.

Back in 2002, American Airlines Flight 282 approached New York’s JFK. It was a Boeing 757 that landed with chewed-up electrical cables. Crew members heard noises coming from the cargo hold and found that some aircraft radio and navigational equipment wasn’t working. A dog had chewed its way through a cargo bulkhead and attacked wires in an electronics compartment. 

A quick search reveals that there are more cases of incidents caused by loose animals than might first be thought. Animals are potentially hazardous cargo. Sadly, often these flight incidents are not good for the animals concerned.

One thing to remember is that a large aircraft, at flight altitude, is pressurised. That’s not at the air pressure on the ground (unless an airport is a long way up a mountain range). A dog with breathing difficulties is going to find an aircraft environment distressing. Dogs can be skillful escape artists. Myself, I’m not keen to share a flight with them.

[1] https://intradco-global.com/livestock-transport/

[2] https://www.thesun.co.uk/news/33273791/cat-causes-chaos-ryanair-plane-rome/

The Swiss Cheese Model in Aviation Safety

Models in safety thinking take different shapes and forms. A conversation might start – what’s a model? Why are they useful?

Here’s a go at an answer. It’s always risky to explain why something works. It can be like a dry analysis of the particulars of a good joke. That kills the essence. As the words attributed to Albert Einstein say: if you can’t explain it simply then you don’t understand it well enough. Even if that’s not literally a quote it sums-up the need for simplicity.

Aviation is a highly complex, interconnected, socio-technical system with a legacy that coexists with rapid advancement. There are few parts of the globe that are not touched by aviation in some way or another. Getting to and from Arctic wastes, commuting between vast cities or traversing the widest oceans. Aviation touches all of them every day.

There is no piece of paper big enough to write a detailed description of every part of the worldwide aviation system. Even the most extensive computer simulations just take on a small part of the whole. I often use this phrase – “it’s more than a head full”. What I mean is that however smart we might think we are, the normal person can only comprehend a slice of what’s happening. A slice frozen in time.

We get over our limitations in perception and understanding but approximating. That is to carve out a “model” of what’s happening and how parts of a complex system interact. That sounds easy enough to construct. It’s a lot harder than first might be thought.

For one, a model needs to be sufficiently universal to capture an underlying reality or theme.

Next, a model needs to be useful. It has utility. It’s proven to work. To produce useful outcomes.

Thirdly, a model needs to communicate a message across cultures, beliefs and disciplines.

A model that meets all the needs described above can be as big an advancement as any hard technology. I guess it’s not surprising that a professor of psychology comes up with one that has been used and reused successfully over decades.

This week has seen the passing of Professor James T. Reason. He’s left us with a legacy that’s almost incomparable. His Swiss cheese model[1] has become a basic part of every aviation safety professional’s training.

I’ve debated and discussed accident causation a lot. The Swiss cheese model[2] is not the only way of thinking about how accidents happen, but it is an extremely good one. It promotes a way of thinking about how to defend against accidents. That’s powerful.

Like all models it’s a simplification of a highly complex system. Its great strength is that this model allows us to see through the mist. To see part of what is obscured by complexity. That is immensely valuable.

Thank you, Professor Reason. 

NOTE: An IFA Video with Professor Reason Every Day – 20 min film – International Federation of Airworthiness.

[1] https://en.wikipedia.org/wiki/Swiss_cheese_model

[2] https://www.eurocontrol.int/sites/default/files/library/017_Swiss_Cheese_Model.pdf

Future of Single Pilot Operations in Aviation

Flying embraces automation. Now, there’s a statement that didn’t ought to be controversial, but it can be. Even before we became engulfed by the modern digital age, analogue autopilots could assist in the task of flying. Some early ones were mechanical.

The need for full-time hands-on piloting of the physical controls that linked a human and an aircraft’s control surfaces is not fundamental. Large transport aircraft have stepped further, somewhat mimicking what their military counterparts did, and fly-by-wire systems have become commonplace.

As far as technological evolution is concerned, we remain in a transitionary phase. Commercial aircraft that fly overhead are a mixed community. Some, like the Boeing 737 series continue to have cables and pulleys that link aircraft systems and controls. Others, like the Airbus A320 series are the fly-by-wire digital aircraft types in regular service.

Between the pilots in the cockpit and the motion of an aircraft there is a computer. In fact, several computers arranged in a manner so that they continue to work even when subject to failures. A great deal of thought and effort has gone into designing aircraft systems that will be reliable in-service.

Looking at the safety numbers, starting in the 1980s when fly-by-wire was introduced, the overall service experience is extremely good. The practice of system safety assessment has delivered dependable and robust aircraft. Rigorous certification processes are applied. 

Through the technical developments that marched on from the 1980s one requirement has remained. That is that two pilots are needed in the aircraft cockpit. Granted there are exceptions to this rule for smaller transport aircraft. Single pilot operations are not new. For example, in many countries, the Cessna Caravan[1] is approved for a single pilot.

It’s 2025. It’s difficult not to notice the debate around Single Pilot Operations (SPO). That is to open large transport aircraft operations to a new rule. Lower operating costs may be achievable by making a change. It’s even said that this move is a way of continuing aviation’s growth as it becomes more and more difficult worldwide to increase the number of qualified pilots.

It’s good to see this subject being taken up in a forthcoming conference.

RAeS Flight Operations Conference 2025: Single Pilot Operations – Logical Progression or a Step Too Far?[2] 19 March 2025 – 20 March 2025. Royal Aeronautical Society Headquarters in London.

SPO may be enabled by use of complex systems to help make mission-critical decisions. The next step maybe with real-time “artificial” copilots and intelligent monitoring. Will this move the aviation industry toward safer and more efficient aircraft operations? That is the question.

[1] https://cessna.txtav.com/en/turboprop/caravan

[2] https://www.aerosociety.com/events-calendar/raes-flight-operations-conference-2025-single-pilot-operations-logical-progression-or-a-step-too-far

Advancements in Flight Recorder Technology and Regulations

My last posting addressed accident flight recorders and airworthiness requirements. That’s not enough. It’s important to note that aircraft equipage standards are addressed in operational rules. So, the airworthiness requirements define what an acceptable installation looks like but as to whether an operator needs to have specific equipage or not, that’s down to the operational rules in each country.

Internationally, the standards and recommended practices of ICAO Annex 6 are applicable. These cover the operation of aircraft. Flight recorders are addressed in para 6.3.1. and Appendix 8. Let’s note that ICAO is not a regulator. There are international standards but operational rules in each country apply to each country’s aircraft.

One of the major advances in accident flight recorders technology is the capability to record more data than was formerly practical. This has led to standards for Cockpit Voice Recorders (CVRs) advancing from 2-hour recording duration to 25-hours.

Proposed rule changes have been hampered by the impact of the global pandemic. Some new operational rules apply only to newly built aircraft. That means some existing aircraft can retain their 2-hour CVRs.

Another technology advance is what’s known as Recorder Independent Power Supply (RIPS). RIPS can provided power to the CVR for at least 10 minutes after aircraft electrical power is lost. The RIPS is often offered as a relatively straightforward aircraft modification.

I do not know if the South Korea Boeing 737-800 was required to have accident recorders with the capabilities listed above. If they were not, then there’s a good basis for recommending that changes be made to existing aircraft.