Category: Safety

Fatal Aircraft Accident Investigation – Update

Given the tragic nature of VoePass Linhas Aéreas flight PTB2283, it is a fatal aircraft accident investigation of global importance. The Brazilian Aeronautical Accidents Investigation and Prevention Center (CENIPA) is investigating. CENIPA investigations are based on the international standard, namely ICAO Annex 13.

Both the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR) of the civil aircraft, registered PS-VPB, have been successfully replayed[1]. This is a task that required great care and diligence. The replay data now available to the investigators for detailed analysis, is of the utmost significance.

From the pictures available the external impact damage to the flight recorders is evident. What is important is that the crash protected memory module works as intended. This is solid-state digital memory that is packaged in a way that protects it from extreme conditions.

Finding from this accident investigation could have implications for the whole ATR aircraft fleet worldwide. It’s certain the authorities in Brazil will notify the aviation community if findings indicate corrective action that needs to be immediately taken.

Reports in the public domain indicate that the ATR aircraft had an ice detection system and that alerts could be heard in the cockpit during the flight[2]. Additionally, there is the indication that the crew acted in relation to those cockpit alerts.

[My apologies for a post where I suggested that there may not have been an ice detection sensor and alert on this class of turboprop aircraft. I was in error.].

This chain of events may suggest a simple set of explanations for the loss of control of the aircraft as it approached its destination. However, these matters are never simple, as most catastrophic aviation accidents are a combination of factors.

Even though the crew noted that there was icing, there is, as yet, no indication that the atmospheric conditions experienced by the aircraft in-flight were of a truly exceptional nature. The ATR aircraft is certified for specific icing conditions. There is training and procedures for the encounter of icing conditions.

It is pure speculation on my part, but I am reminded of an aviation accident of more than 40-years ago[3]. The conditions of the accident are different, but a factor may link the two. The last line of the NTSB report abstract says: “and the limited experience of the flight crew in jet transport winter conditions.” A small amount of ice contamination in the wrong place at the wrong time can have much more impact that might be immediately assumed.

[1] https://www2.fab.mil.br/cenipa/index.php/ultimas-noticias/1766-cenipa-extrai-com-exito-dados-dos-gravadores-de-voo-da-aeronave-ps-vpb

[2] https://www.flightglobal.com/safety/voepass-atr-crash-probe-analyses-crews-response-to-ice-alerts-before-fatal-flat-spin/159888.article

[3] https://www.ntsb.gov/news/press-releases/Pages/mr20220112b.aspx

Brazilian Air Crash

Two weeks have elapsed since the tragic loss of VoePass Linhas Aéreas flight PTB2283[1].

Reports are that the Brazilian air accident investigators[2] have successfully downloaded recordings from the aircraft Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR).

A detailed analysis of both recordings should provide a replay of the flight events on the fateful day. This means that any flight anomalies can be interpreted. Both actions of the crew and the response of the aircraft can be used to understand the sequence of events.

Those conducting the analysis will need to verify the past serviceability[3] of both recorders. It’s easy to assume that what’s presented in the recovered replay is what happened. However, that depends on the calibration of sensors and the correct functioning of the aircraft’s audio system.

CVRs and FDRs are primarily tools for the investigation of accidents and serious incidents by investigating authorities. Accident recordings can be a rich source of information. It’s not just the obvious contribution technical records make to an investigation. The CVR, via a cockpit area microphone picks up much more than just the speech of the crew and their communications with air traffic. Engines, propellers, aircraft warning systems, aerodynamic noise and the impact of structural failures all produce audio signatures.

I assume that the aircraft operator has a Flight Data Monitoring Program. Such a program can support continuing airworthiness and operational safety of an aircraft. It can be a vital part of a Safety Management System (SMS). Also, the regular analysis of flight data is one way of ensuring that the serviceability of the data acquisition system for an FDR is known.

A preliminary report on this fatal accident is expected in early September. It is up to CENIPA if the publish any transcript of the accident recordings.

VoePass, the airline in question, operates a regional network in Brazil. Not surprisingly it has now come under greater scrutiny by the Brazilian aviation regulator, Agência Nacional de Aviação Civil (ANAC).

It’s worth noting that the Brazilian civil aircraft fleet is one of the largest in the world. It’s a sizable country. Both ANAC and CENIPA are well experienced in addressing the aftermath of a major aviation accident. Expectations are high that the causes of this fatal accident will be fully understood. Appropriately then corrective action will be taken.

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

[2] Brazilian Aeronautical Accidents Investigation and Prevention Center (CENIPA)

[3] https://www.caa.co.uk/publication/download/12811

Navigating Speculation in the Age of Abundant Information

Speculation is a natural human response. When faced with a paucity of information we often put together what we know and then make a best guess as to what happened or what might happen. However, wise or unwise it’s not possible to stop speculation. Well, that is assuming that autocratic power doesn’t use force to crush the free exchange of ideas.

Since the rise of the INTERNET, with a proliferation of all kinds of material, it becomes less and less possible to quell speculation. A sprinkling of information can grow into a monstrous conspiracy but equally it can grow into a stepping stone to greater understanding. Living with this two-edged sword is our modern dilemma.

In a more deferential society, that we may have been immediately post WWII, officialdom was accustomed to restricting information. The principal of “need to know” and statements like – wait for the official report – were enough to quell Press intrusion and intense public curiosity. On occasions this deference turned out to be tragic and been an enabler for authorities to cover up dreadful errors and failings. My mind goes to the Hillsborough disaster[1] when I think of tragedies made worse by the manipulation of information.

What’s all this about – you might say. I’m giving a thought to the post- accident scenarios that become more common. When major fatal transport accidents happen to planes, boats and trains there’s an instant demand for detailed information.

This is happening in relation to the recent Brazilian ATR aircraft accident and, this morning, to the sinking of a large modern yacht off the coast of Sicily. Both tragedies seem astonishing in their own way. So much of our technological world works so perfectly, a great deal of the time, that we get accustomed to reliability, safety and security. Almost taking it for granted.

Basic technical information, like registration numbers, type and age of the vehicle all surface quickly after an event. Even numbers of fatalities are verified within a couple of days. What gets the speculators going is the answers to the question – why?

A list of circumstantial factors can soon emerge. The time, the weather, the location and the organisations involved. All of this creates a mix that feeds both intelligent and unintelligent speculation. I’m not saying this is de-facto bad. It’s reality.

What’s all this about? There are reports across the media of the “last words of Brazil plane crash pilots.” This speculation surrounds the words spoken in the cockpit and seem to come from someone’s knowledge of a transcript. How can that be? Through international agreement the independent aviation investigation organisations across the globe are committed to a protection of this type of recorded information (Cockpit Voice Reporter (CVR)[2]). Accident flight recorders are there for the purposes of the investigation of an accident or incident.

Back to our modern dilemma. Is it good or bad that sensitive protected information leaks into the public domain before it’s been thoroughly analysed and properly understood? There is a cost to a dilution of the protection of information. For one, it may discourage the voluntary application of safety enhancements, like fitting a recorder to a plane, boat or train.

[1] https://www.bbc.co.uk/news/topics/c8m8v3p0yygt

[2] https://skybrary.aero/articles/cockpit-voice-recorder-cvr

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

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.

Mars steps

It’s strange what thoughts circulate in my head. If I was to say what kicked this off it was probably the story of the Preet Chandi[1]. It’s inspiring how some people see a challenge and just get up and throw themselves into overcoming it. Her commitment and determination are impressive. She was recounting the how and why of her striking endeavours on the radio. What’s much less inspiring are a some of the moronic comments that the web throws-up about her achievements. I hope she continues to take on great challenges and sweeps them aside.

Exploring and going that extra mile is built into the fabric of being human. Fine, it’s not for everyone but that’s no surprise given that there are 8 billion of us on this planet. A magazine popped through my letterbox this week speculating on what Earth will be like when that number gets to 10 billion people. Don’t worry it’s not all doom and gloom. It’s just that the world will be a very different place by the time we get to 2050. Wow, if I stay healthy, I might still be around.

A lot of public policy of the moment seems to be resisting this reality. Honestly building barriers and walls will do nothing whatsoever to build a better world. Cultivating political anxiety and fears about the future is the maddest short-termism that can be imagined. But sadly, there’s a lot of it about. It’s fashionable in the mature democracies around the globe.

Humanity has an endless list of “challenges” and opportunities ahead. Now, I don’t what to sound too much like the Musk man but we’ve a great deal to do off the planet. What we’ve achieved so far is chicken feed in respect of what we have the potential to achieve.

The big one, that taxes the imagination of writers and futurologists is what do we do about our sister planet: Mars. It’s impossible to ignore. It’s not that far away when compared with other distances in space. It’s intriguing in that it was once a water world. Like Earth.

Today, it’s a planet inhabited by robots. The only one we know that is so populated. Rovers drive around sending pictures back of a desolate barren landscape that has an eery beauty. So much of what we know about the place has only been discovered in the last decade.

Human exploration is natural and normal. Do we leave it to robots? Afterall they are becoming ever more sophisticated. Or do we plant boots on the ground and go there to explore in the way we have throughout the Earth. Well, except for parts of the deep ocean.

Here’s what crossed my mind. Just as Polar Preet, broke two Guinness World Records on her journey, so the incentive to be the first person on Mars is something that will land in the history books. The name of the person who makes those steps will echo through the centuries ahead. So, the trip to Mars will not need an incentive. The drive to do it, at almost any cost is already hanging in the air. What’s more complicated is the journey back to Earth. Going on an expedition has a clear goal. Getting back from an expedition has a different goal.

Being someone who recognises the benefits in the reliability of redundant systems it occurs to me that a mission to Mars needs two ships and not one. Both traveling together to the planet. One can be simple and utilitarian. That’s the one crewed as the outward-bound ship. The other, the homeward ship needs to be autonomous, secure and even luxurious. That way the hardest part of the journey, coming back, can be made easier and more likely to succeed.

[1] https://www.independent.co.uk/news/uk/home-news/preet-chandi-sikh-south-pole-b1987047.html

Harmonisation

There’s an example in of itself. I’ve used the British English spelling. Perhaps I should have standardised on the American spelling, namely Harmonization. Or does it matter at all given that the definition of the word remains the same, whatever. Oh, I can’t resist the temptation to say; you say Tomato, I say Tomato.

“You say tomato, I say tomato.

You eat potato and I eat potato,

Tomato, tomato, potato, potato,

Let’s call the whole thing off.”

Naturally, in the voice of Fred Astaire[1]. Nice though this is, my subject is not pronunciation.

Aviation is a highly regulated business. It’s been that since its potential for transporting huge numbers of people around the globe was recognised. Safety must be number one. Although, it’s not if you read the first few words of the all-important Chicago convention.

Article 1: Every state has complete and exclusive sovereignty over airspace above its territory.

In the minds of those who signed the convention it was sovereignty that took first place. That didn’t mean abusing the word “sovereignty” as has to often been done. Afterall, the whole basis of the Convention on International Civil Aviation was international cooperation. It still is.

Let’s put that to one side for a moment. One of the challenges of international aviation has been the different rules and regulations in place in each country. There’s a level of harmony in the standards of the International Civil Aviation Organization (ICAO). But ICAO is not a regulator and it’s for each country to interpret agreed standards within their domestic law.

Europe, or at least the European Union (EU) is different in this respect. Since there’s European law and an active European regulator then there’s common rules and regulation set for a regional grouping of countries. So far, Europe is the only region to go this far.

When it comes to aircraft airworthiness this has been a topic of a lot of discussion in the last four decades. In the 1990s, that discussion centred around the idea that a single worldwide code was a desirable achievement. That the time the two major entities engaged in the business of aviation rulemaking, and the maintenance of rules were the FAA (US) and the JAA (Europe).

A single worldwide code could greatly facilitate the movement of aviation produces around the globe. That done to ensure that common safety standards were maintained on every occasion. It proved hard to get to this utopian condition. That said, a great deal was achieved in the harmonisation of existing civil aviation codes. Today, we benefit from that work. I’d say we even take it for granted.

In around 2000, after much study, countries concluded that it was fine to seek some form of equivalence between respective rules rather than having to write done one single set of rules. Mutual recognition has flourished in the form of agreements between countries that has smoothed the path for the aviation industries.

That last major study of the pros and cons of harmonisation is now nearly a generation old. A lot has moved on. For one, in Europe the JAA transition to the EASA.

At the same time the manufacturing countries worked closely together to agree on measures to ensure that there was no great divergence in rules and regulations. Now subjects, like Safety Management Systems (SMS) became codified. However, sovereign countries continued to develop and maintain their own aviation rules and regulations.

International working groups often achieve remarkable commonality and convergence on detailed technical topics. Often because the few people who were deeply embedded in a technical subjects all knew each other and shared information relatively freely.

Discussion as to the viability of a single worldwide code has not completely faded into the past. In fact, there’s some good reason to breath life back into this historic debate. Here’s what’s added to the dynamics of the situation:

  1. Ongoing moves from prescriptive rules to more performance-based rules,
  2. Entirely new products in development, like eVTOL aircraft,
  3. Interdependency, interconnection, and integration all increased since 2000,
  4. Security and safety are becoming inseparable,
  5. Digitisation is changing the ways that we ensure that an aircraft is airworthy.

If you have knowledge of, and thoughts on this subject, I’d be happy to hear from you.

[1] https://youtu.be/LOILZ_D3aRg

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:

  1. Propensity of one branch of technically capable people to find mechanical work less fearsome and more satisfying than electrics or electronics, and
  2. 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.

  1. 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.
  2. 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.
  3. 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