Systems – Page 9 – John Vincent

Tragic VoePass ATR72 Crash

2024 was going so well. Looking at the indicator of worldwide fatalities in commercial aviation for the first six-months of this year, and it is exceptionally low. The time between major fatal accidents across the globe is another indicator that my team once looked at on a regular basis. Aviation is an extremely safe mode of transport but when accidents happen, they can be devastating.

Yesterday, the situation changed in Brazil. A VoePass ATR72-500 aircraft[1], registration PS-VPB, flight number PTB2283 crashed in the Brazilian state of São Paulo. The twin-engine aircraft crashed in a residential location.

Yet unknown events resulted in a loss of control in-flight. On-line videos of the aircraft flying show a dive and then a spiralling decent to the ground. The aircraft was destroyed on impact, and it is reported that all lives were lost.

The publicly available flight data shows a sudden decent from a stable altitude[2]. The aircraft was about and hour and twenty minutes into its flight.

Looking at the video information it might appear that local weather may not have been a factor in the accident. However, there was known to be severe icing conditions at the altitude that the aircraft was flying.

It’s speculation on my part but unrecognised severe icing is one of the conditions that can bring about a catastrophic outcome for such an aircraft. It is sad to have to say that there is a record of a major accident to an ATR-72 that has some of the characteristics of this new accident.

In fact, it is one fatal accident that is etched on my mind given that it happened in late 1994, when I was still fresh in my job with the UK Civil Aviation Authority as an airworthiness surveyor. It’s known as much by its location as by the name of the aircraft, namely Roselawn[3]. The accident was extremely controversial at the time.

Crews are told that they may be operating in severe icing conditions but there is no specific regulatory requirement for on-board advisory or warning system on this generation of turboprop aircraft. An ice detection system can serve as a final warning to alert a crew that ice protection is needed.

Work to update the technical document; In-Flight Ice Detection System (FIDS) Minimum Operational Specification EUROCAE ED-103 is completed. Issued in April 2022, ED-103B – MOPS for In-Flight Icing Detection Systems is available[4].

In the case of the current accident, it is a matter for Brazil’s highly capable independent accident investigators to determine what happened. Anything I have written here is purely speculative.

POST 1: Reports of statements made by Agência Nacional de Aviação Civil (Anac) say that the aircraft was in good condition.

POST 2: Accident flight recorders have been recovered from the accident site. Flight recorders retrieved from crashed Voepass ATR 72-500 | Flight Global

[1] https://asn.flightsafety.org/wikibase/409335

[2] https://www.flightaware.com/live/flight/PSVPB/history/20240809/1450Z/SBCA/SBGR/tracklog

[3] https://www.faa.gov/lessons_learned/transport_airplane/accidents/N401AM

[4] https://eshop.eurocae.net/eurocae-documents-and-reports/ed-103b/

Electric Aviation: The Promise of Clean Flight

Electric aviation is not new. Not new at all. The engineers of the past struggled with two factors. Power and weight. A French electrically powered airship was the first aircraft to make a controlled circuit. On 9 August 1884, it flew a circular course of 8 km at a max speed of 14.5 mph. Its electric motor weighed 100 kilograms and its battery weighed 263 kilograms.

It’s not a problem to be able to distribute or use electrical power on-board an aircraft. The problem come in generating enough of it from a reliable source. Today’s “conventional” civil aircraft generate and use large amounts of electrical power. For example, the Boeing 787 has two starter/generators per engine[1]. Electrical power from the generators goes to four alternating current (AC) electrical distribution buses, where it is either sent for use as is (235 V AC) or converted for use by the aircraft systems that need it.

A revolution is taking place in electric aviation. It offers the opportunity to fly cleanly. That said, the traditional technical challenges remain the same. Power and weight. In 140-years battery technology has advanced considerably. But is that enough?

A difficulty that battery powered flying is stuck with is that at the start and at the end of a flight the batteries weigh, more or less, the same as they did from the day of their manufacture. Today’s “conventional” civil aircraft consume fuel. Thus, they are significantly lighter at the end of a flight than they are at the start. Airframes can be designed to take advantage of this fact.

One of the up sides is that a good electric motor can get to an efficiency of 80% whereas a turbo fan engine comes in at around 35%. That sound great until we look at the amount of energy we can store within a given volume. Jet fuel packs a punch. To get the same punch from an electrical battery it would likely be 15 times the size. That’s not good for a practical design. The low battery energy density coupled with the high weight of batteries means that this strategy for large aircraft needs to be put to one side for now.

A modern aircraft engine like the CFM International LEAP, can develop a max take-off thrust of over 30,000 lbf. Two of those engines can safely accelerate a Boeing 737 or Airbus A320 with ease and cruise with good economy. Thus, electrification of the propulsion of this class of aircraft is a long way off. The nearest possible future for propulsion of a B737 and A320 sized aircraft may be hydrogen based.

This explains why the drawing boards are full of small electric aircraft designs where performance demands are more modest. There’s a hope that the continuous development of battery technology will provide year on year gains. Much more than aviation alone demands that battery technology advances.

Developments in hydrogen-electric aviation are catching the headlines. Much of what has been achieved is experimental. I look forward to the day when hydrogen is not used to fill airship gas bags but becomes the life blood of transport aviation. It’s conceivable that will happen in my lifetime.

[1] http://787updates.newairplane.com/787-Electrical-Systems/787-Electrical-System

Solar farms

New Government signs off solar farms. Not everyone happy.

It would be good if we could all agree that the UK needs to recognise the importance of locally produced food and drink. There’re large environmental gains to be made by reducing the distance between production and consumption. Thousands of heavy trucks thunder up and down the inadequate road infrastructure in the UK. Colossal amounts of food waste get thrown away from supermarkets. Questionable preservatives enable supply chains to grow longer and longer. There’s are bad trends.

On a related subject, I do have a problem with proposals for large solar arrays that will take out productive farmland. However, that is by no means an objection to large solar arrays, or onshore wind farms for that matter.

It’s not as if we have always been so precious about what we do with our glorious countryside. One observation I’d make is that there has been a huge increase in the urbanisation of the countryside in my lifetime. Areas that were either wild or exclusively used for agriculture are now pony paddocks, car parks, golf courses, housing estates, out-of-town shopping warehouse, fulfillment centres[1], and bypasses. In 50-years, there’s little that remains untouched.

I’d sing “They paved paradise and put up a parking lot” if I could. We really do need to think carefully about what we industrialise and what we preserve and protect.

For me large solar arrays are in the same category as acres of poly tunnels. Both serve a fundamental purpose, and both are structure that can be relatively easily removed. Keeping the lights on and eating fresh food are both part of society’s basic needs.

So, I’m not going to raise an eyebrow at new Minister Ed Miliband approving 3 large solar arrays[2]:No shock but no blank cheque either. No jumping on a political bandwagon to condemn the immediate decision.

It’s likely the decision was sitting on the former Conservative Minister’s desk. Is this a case of difficult decisions deliberately delayed because of an election? We may never know. It would be a bit disingenuous for such politicians to complain now. Wouldn’t it?

Let’s get it right. Failure to decarbonise our national energy system is a contribution to global warming we can’t afford to make. Long-term that global warming will impact food production.

In years to come it will be interesting to see what research flags up with respect to solar farms and biodiversity in an area. There’s some chance that the results will not be entirely negative. There’s all that sheltered and undisturbed soil under the array structures. A habitat for wildlife.

Choosing between what might seem as the lesser of two evils is often the situation a politician finds themselves in. Afterall, that’s the role they must play in a democracy. The outcome may not be popular in the short-term, but a balance must be struck.

Maybe we should reverse some of the urbanisation of the countryside. Return some little used roads to nature. Demolish unused industrial units. Put back the hedges that have been lost. Rewild one or two golf courses. It’s something to consider when building new infrastructure.

[1] Fulfillment centres enables outsourcing, warehousing and shipping. This is for online businesses to have the physical space to store stuff.

[2] https://www.bbc.co.uk/news/articles/c4ng6036vgqo

Rethinking the House of Lords: Toward a Balanced and Democratic Approach

Good to hear that there’s a prospect of House of Lords reform in next week’s Kings speech. Change is on the agenda.

It’s astonishing that “hereditary” is a valid qualification for the job as a legislator. I’ve nothing against the individuals involved. Especially those who try to do the best they can. Put all that to one side, there’s a huge gulf between what’s normal in normal life and what’s normal in the Place of Westminster. It’s time to consider merit as more important than who your parents were.

The removal of hereditary peers should be just a first step. One of the most egregious unfairnesses is that way the HoL gets topped-up with political cronies a regular basis. We’ve institutionalised political tribalism in the second chamber. Ennobling people for dubious reasons has become a habit of Prime Ministers. Making contributions to political Party funds should not be a ticket to the HoLs.

There’s the religious element too. Whereas there’s a lot to be said for a level or moral guidance to be given to Peers there’s little justification for them to have votes in the HoL. I’m not denying the important part region plays in many people’s lives. What I am saying is that the laws that affect every citizen shouldn’t be shaped by a small cohort of clerics. Two countries have religious clerics in places of legislative power, and they are UK and Iran. That doesn’t sit well with me, and no doubt most people.

One change maybe controversial given that it smacks of discrimination and that is the setting of an age threshold. If Peers are given a compulsory retirement at the age of 80, it may meet an objective of getting the overall number of Peers down. What disconcerting is the implication that beyond the age of 80 a Peer’s potential contribution is less valuable.

I don’t agree that the compulsory retirement age for the HoL should be set at the state pension age. For some people age does mark a dimming of their intellect but for others they can be as sharp as a pin. The only easy option is a fixed threshold, but it should be a temporary measure.

Ideally, the size of the HoL should be fixed. Ideally, the size of both chambers should be similar. Not just because that number line-up but because the political weight should be set closer to a balance. I do assume in this formula that every Peer is a working Peer.

It’s been pointed out that in its current state the HoL makes it the second largest political chamber in the world. It’s reached ridiculous proportions for a country of our size.

Modest changes can only be a start. There’s the real need for permanent restructuring. Parliament’s second chamber must be replaced with a democratic upper house. One model would be an elected upper house with two members elected per UK region based on current/proposed metro mayoral regions or former regions used for electing MEPs.

Even the chamber’s name must go. It’s not good that we have legislators lording over us. Those sitting on the red benches are not superior beings. They are privileged. One would hope for them to be humble given that great privilege. Afterall they should be there to serve us. To serve the country.

Just Culture

My thought is that we’ve forgotten the discussion of more than a decade ago. There was a time when the thoughtful reflections on responsibility and accountability were much discussed.

Without focusing on specific examples, there are plenty to choose from, there’s the propensity of our institutions and politicians to reach for “blame” as a first response. When situations go bad the instinctive inclination to hunt out someone to blame. This is an all too prevalent habit.

Naturally, in cases, there’s the strong need to identify who is accountable for bad decisions. Society does not like it when the powerful protect, cocoon themselves and grab for immunity. Certainly, some people and organisations are genuinely blameworthy. However, if we scrutinise and point the finger of blame, it doesn’t help if that finger is pointed at a person’s honest errors. There isn’t a human on this planet who hasn’t made an error.

The finger of blame is easily pointed. Judgment so often falls after an event. The time when more is known, and hindsight comes into play. This tips the balance. It’s so much easier to say: why on Earth did you do that? I would never have done that.

For people to come forward and be fairly heard in an open and fair inquiry or investigation they need to have the confidence that they are not stepping into a public blame-fest. Without trust between those on all sides of it’s less likely that the truth will come out.

“Just Culture” is a concept written into aviation legislation and followed by others. The overriding aim is to learn from mistakes. It’s the surest way of not repeating the same mistakes time and time again. It’s beneficial to have that long-term learning objective. Why suffer the pain of a bad event when the means to avoid it are known and understood?

Now, I’m going back 20-years. I remember being part of an international working group[1] called GAIN. The group compiled guidance about organisational culture. At the time, the group was considering the subject in the context of the air traffic profession. Guidance like the one referenced, emphasise that a Just Culture is not simply a no-blame culture. It’s not, and never has been a way of circumventing accountability.

Determining culpability can be complex. There’s often a test to consider the wilfulness of the participants in a bad event. In other words, did they carelessly, intentionally, maliciously or negligently make decisions that resulted in the bad event? In these cases, the “they” could be an individual or an organisation.

Gross negligence, wilful abuses and destructive acts should be addressed by the enforcement of laws. If we say the criminalisation of honest people involved in bad events has a negative impact. That is not to negate the need for enforcement. Regulators in all sorts of walks of life have a duty to apply enforcement where and when it’s appropriate. Maybe we ought to have applied that to the UK water industry.

My plea here is to first consider the nature of the events in question. Was there an element of genuine honest human error? Is the right balance being struck between the need to learn and the need to ensure accountability?

NOTE: Just Culture is defined in EU law as “A culture in which operational staff or others are not held accountable for actions, acts, omissions or decisions commensurate with their experience and training, but gross negligence, intentional violations and destructive actions are not tolerated” EC 376/2014 Art. 2 Para. 12.

[1] A Roadmap to a Just Culture https://flightsafety.org/files/just_culture.pdf

Rapid

Such a rapid change. In days we go from one governmental regium to another. The government of the UK has changed. It’s now dramatically different from what it was only a couple of days ago. It’s not overstating the case to say dramatic. On a relatively modest percentage of the overall national vote the Labour Party has been handed all the leavers of power.

The UK’s main electoral system is not proportional. It tends to exaggerate and distort performance. Lifting those who do well in the national vote numbers but suppressing those who are supported by smaller overall percentages. Interestingly, the Liberal Democrats, who have always been in favour of a proportional representation electoral system, have an approximate match between the number of seats won and the number of votes cast across the country.

Sticking with the positives, this rapid change does mean policy resets are possible. One significant example is the immediate scrapping of the policy mess that the previous government had got itself into over immigration.

Accepting a fresh start has a upside. However, the difficulty that can present itself is the challenge to continuity. Lots of new faces with new responsibilities. Lots of people learning the ropes. One answer to that challenge is to say that the civil service provides a seamless continuity. The mandarins in Whitehall guide the ship of State through the transition. Not only that but many of the people coming into power have been preparing for this opportunity for a long time.

The difficulty is that the mismatch between the national percentages of the General Election vote and the number of Westminster seats held is there for all to see. It’s a stark indicator of the reality of people’s wishes verses the outcome of a process.

I was a counting agent standing in a sports hall until the early morning totting-up an estimate of the vote for a political party. Pen in hand watching officers carefully unfold paper ballots. In a world of smart phones and tablets there’s something very retro about looking at piles of black and white paper for hours.

One aspect of First Past The Post (FPTP) is the theoretical simplicity of the counting process. Naturally, it’s far from simple. One cross, in one box is well within the capability of every kind of voter. However, it’s crude in terms of what it says about the voter’s views. It forces everyone to make stark choices. There’s no accommodation of preference. Say, you are a person who’s essentially conservative or socialist but can’t stand that Party in its current form, you are forced to leap to vote, if you vote at all, for a political candidate that may not be your natural choice.

So, society ought to ask itself, do we value the result of the electoral process most? Or do we value the expression of the individual preference the most? There’s an inevitability to the answer to that question, if the horizon set is a long one. Where so much of what we now do is addressed by algorithms designed to distil our individual preferences how can we stick with a paper based last century electoral system that ignores preference?

Change will come one day. The difficulty is that if the UK’s FPTP electoral system offers no incentive to the winning Party to change it, so we will be bound to stick with it. Well, at least for the next few years.

Turbulence

Turbulence is the result of atmospheric or environmental effects. Afterall, aircraft are craft that fly in the air. This is a hazard that is inherent in flying. Clear air turbulence (CAT) is common. However, extreme examples experienced in commercial aviation are rare. For one, aircraft operators and their crews do their best to avoid known potential atmospheric or environmental upsets, namely bad weather.

En-route turbulence accounts for a substantial number of cabin crew members injuries, and can occur at any time and at any altitude[1]. As far as I know, the UK Civil Aviation Authority (CAA) does not hold detailed data on turbulence injuries occurring on foreign registered aircraft. Numbers of injuries to passengers and flight crew on UK registered aircraft resulting from turbulence are recorded. However, it is not always known whether those injured in turbulence encounters were wearing seat belts.

Nevertheless, I can confidently say that the more passengers that are wearing seat belts during turbulence encounters the less the number of injuries. Deaths in these circumstances are rare. As might be expected fatalities are more likely to results from a combination of multiple causes and factors.

This subject is not immune from airline economics and competition. International flight routes can often be highly competitive. Fought over. So, the route taken, and associated fuel costs, can have an impact on the likelihood of a hazardous weather encounter. In fact, choosing to take routes for the benefit of picking-up specific winds is a common practice.

A high percentage of cases of turbulence events come about by flying too close to active storms[2]. Here there is often visual cues, reports, forecasts and feedback from turbulence encountered by other flights. This all helps crews avoid the worst weather encounters.

With very few exceptions, flight turbulence does not result in fatalities, permanent injure, or structurally damage commercial aircraft. However, turbulence is recognised as both an aviation safety and an economic issue, and it has been steadily increasing. Speculation and some research cites climate change as a reason for this increase. Also, there is the international growth in air traffic and development of new long-range routes.

One thing to say is that until recently, with INTERNET connections now in both in the cockpit and cabin, it could be the case that a passenger could access better real-time weather information than a flight crew. Now, SATCOM connections providing up-to-date weather information are more common on modern civil aircraft types.

There is still more that can be done to reduce crew and passenger injuries during turbulence encounters. There will inevitably happen despite any policy to avoid hazardous weather. The greatest threat to life exists to cabin crew. The cabin is their place of work.

There is potential to develop and employ better airborne detection systems to assist crews. That maybe by enhancing existing weather radar systems. It maybe by new means of turbulence detection using LIDAR, and possibly AI/ML. There is research and innovation that could be done to develop algorithms to better predict turbulence hazards.

Avoidance remains the best strategy.

[1] NASDAC Turbulence Study, August 2004

[2] US CAST briefing in 2004.

Challenger

It’s another phrase from HHGTTG. “Mostly harmless”. However, there are things that may seem mostly harmless that subsequently turn out to be far from harmless. It’s that law of unintended consequences playing out in real life.

In the UK, we are stuck with the First Past The Post (FPTP) electoral system. There is no good in pretending otherwise. Pretending that its perverse effects don’t exist is pure folly. Voting systems inevitably impact the results of elections.

What FPTP means is that the more parties, and their candidates that there are standing in an election, in each constituency, the more the votes cast can be spread. This reality often gives a big advantage to the incumbent. The one who came top of the poll last time votes were cast.

Thinking can go like this. The past winner always wins around here. So, my vote doesn’t count. If a past winner reinforces the impression that nothing has changed, then nothing will change. Because of this feeling of acquiescence, opposition voters may be more inclined to vote for a wide range of fringe candidates. Again, the thinking is that this doesn’t matter because the outcome of an election is a foregone conclusion.

In a lot of places up and down Britain this is how both Conservative and Labour politicians have stayed in power. It’s not because people think they are doing a good job. It’s more because their most immediate opposition struggles to marshal a concentration of votes for an alternative.

The conclusion from these facts is simple. If you are a voter who wants to see change then go for the opposition candidate likely to get the greatest number of votes. This is sometimes called tactical voting. It’s not so much tactical as realistic pragmatism aimed at bringing about real change. Look at the numbers. Unless the individuals concerned are one in a million, those formerly in 3^rd place, or further adrift are there to do their best but not to bring about change. A vote for a mostly harmless candidate, way down the order, just helps to keep the current Member of Parliament in place.

2024 is a year of great potential. If change were ever needed it ‘s now. I’m confident that the British electorate is savvy enough to choose the path to change. This may mean choosing differently. This may mean taking a close look at the local situation.

No doubt a succession of bar charts will highlight who’s up and who’s down. Take a close look at them. Make sure the challenger really is the challenger. If the numbers say so, and you want change – go for it.

Electrics & Mechanics

Yesterday, I wrote on LH2. The potential fuel for electric aircraft of any size. Yes, I’m not just talking about smaller commuter class transport aircraft.

Let me take some anecdotal evidence from the transition that is going on in road transport. Repairer turns up to fix an electric car that will not start. It’s a simple matter given that the car has been standing unused for a long time. The battery had discharged. A quick charge from another battery pack and all is well. Meantime in conversation it’s clear that the repairer hates working on electric cars. I could say, no surprise, they were trained on combustion engines and have been forced to make a transition in technology.

What’s evident here is the apprehension of a person who likely has a mechanical bias towards their work and the necessity to take on fixing powerful electrics. Mechanics, those who love working with moving parts, often have a dislike of electrics and electronics. It’s an engineer’s “feeling” expressed to me casually over the last 40-years.

In fact, it can be the reason that a design or maintenance engineer took the career path that they did. There is a dividing line between mechanical engineers and electrical engineers that is embedded in our institutional, educational, and training systems.

So, there’s two practical human issues to grapple with in a transition:

Propensity of one branch of technically capable people to find mechanical work less fearsome and more satisfying than electrics or electronics, and
Streaming that is embedded in our institutional, educational, and training systems. Qualifications and recognition are often not so multi-disciplinary focused.

I’m not for one single moment making a luddite argument that mechanical engineers[1] and electrical engineers[2] are two tribes that must be kept apart. Far from it. What’s more important is to recognise that transitions are hard.

New electric aircraft are going to demand technical people with a multiplicity of both mechanical and electrical knowledge. The way the engineering world has been divided up in the past doesn’t cut it. Some of our most cherished niches will need to be challenged.

Transitions of this nature always take much longer than is originally anticipated. In a way, that should be such a surprise. It’s a generational change for a community that can be conservative with a small “c”.

This is NOT business as usual. For example, handling powerful 1000-volt electric technology is not for everyone. Removing and replacing cryogenic plumbing is, again, not for everyone. The hazards are clear. The skills needed are clear.

Reorienting the aircraft maintenance engineering world is going to need new plans and programmes. Better start by enthusing people about the change rather than just forcing it.

[1] https://www.imeche.org/

[2] https://www.theiet.org/

Hydrogen in Aviation

The potential for LH2 (liquid hydrogen) is enormous. That’s matched by the logistical and technical difficulties in exploiting this gas’s great potential. It offers energy for a means of propulsion that is nowhere near as environmentally damaging as existing means.

Society already integrates hazardous liquids and gases into everyday life. Each one has been through several iterations. It has been a rollercoaster. Each one has been at the root of disasters, at one time or another.

We use gas for cooking and heating in domestic settings. Periodically explosions demolish buildings. Leaks cannot be ignored. Harm can be done.
We use light and heavy oils widely in transport systems. Periodically intense fires burn vehicles. Care in handling is essential. Harm can be done.

Without having to say it, both above harm the environment. The search for non-CO2 emitting ways of flying is urgent. Here, I’m writing about harm to people. Physical harm. The business of aviation safety.

Often the physical harm is not associated with the design of the systems used but to the maintenance of those systems. Naturally, there was a learning curve. If we look at early versions of those systems, fatal accidents and incidents were far more regular. So, here’s the challenge for aviation. How do we skip the dangers of the early learning phase? How do we embed rigorous maintenance practices from day one? Big questions.

On the first one of these, lots of fine minds are engaged in putting together standards and practices that will address good design. If this works, and it will be tested extensively, the chance opens for introduction to service with a great deal of confidence that the main risks will be managed.

On the second of these, there’s not much happening. You might say there’s an element of chicken and egg. The shape and form of future LH2 systems needs much more work before we can think deeply about how they will be maintained.

I think that’s wrong. It’s old-fashioned thinking. As the industry has often practiced, making the systems first and then devising ways of maintaining them while in-service. That’s yesterday’s reasoning.

Making aviation system maintenance the Cinderella in the LH2 world is to invite failure. This is a situation where advancing the consideration of how the in-service realm could work, day by day, is necessary. It’s advantageous.

Here’s my reasons.

There are generic approaches that can be tested without knowing the detailed design. That can take existing learning from other industries, like chemical and space industries, and consider their application in aviation.
Emerging technologies, like machine learning, coupled with large scale modelling can provide ways of simulating the operational environment before it exists. Thereby rapidly testing maintenance practices in a safe way.
It’s imperative to start early given the mountain that needs to be climbed. This is particularly true when it comes to education and training of engineers, flight crew, airport and logistics staff and even administrators.

Everyone wants to accelerate environmentally sustainable solutions. When they do get to be in-service, they will be there for decades. Thus, an investment, now, in study of maintenance systems will pay dividends in the longer term. Remember, early fatal accidents and incidents can kill otherwise sound projects or at least put them back on the drawing board for a long time.

NOTE 1: I didn’t mention Liquefied Petroleum Gas (LPG). It’s in the mix. Another CO2 contributor. LPG containers have pressure relief valves. LH2 containers will likely have pressure relief valves too. That said, venting LPG is a lot more environmentally damaging than LH2. From a safety perspective they can both create explosive conditions in confined spaces. Maintenance staff may not need to carry a canary in a cage, but they will certainly need to carry gas detectors when working on LH2 powered aircraft. Our noses will not do the job.

NOTE 2: Events on the subject: https://www.iata.org/en/events/all/iata-aviation-energy-forum/

https://events.farnboroughinternational.org/aerospace/sustainable-skies-world-summit-2024

2024 ICAO Symposium on Non-CO₂ Aviation Emissions