The long history of data communications between air and ground has had numerous stops and starts. It’s not new to use digital communications while flying around the globe. That said, it has not been cheap, and traditional systems have evolved only slowly. If we think Controller Pilot Data Link Communications (CPDLC)[1] is quite whizzy. It’s not. It belongs to a Windows 95 generation. Clunky messages and limited applications.

The sluggishness of adoption of digital communications in commercial aviation has been for several reasons. For one, standardised, certified, and maintainable systems and equipment have been expensive. It’s not just the purchase and installation but the connection charges that mount-up.

Unsurprisingly, aircraft operators have moved cautiously unless they can identify an income stream to be developed from airborne communication. That’s one reason why the passengers accessing the internet from their seats can have better connections than the two-crew in the cockpit.

Larger nations’ military flyers don’t have a problem spending money on airborne networking. For them it’s an integral part of being able to operate effectively. In the civil world, each part of the aviation system must make an economic contribution or be essential to safety to make the cut.

The regulatory material applicable to Airborne Communications, Navigation and Surveillance (CS-ACNS)[2] can be found in publications coming from the aviation authorities. This material has the purpose of ensuring a high level of safety and aircraft interoperability. Much of this generally applicable material has evolved slowly over the last 30-years.

Now, it’s good to ask – is this collection of legacy aviation system going to be changed by the new technologies that are rapidly coming on-stream this year? Or are the current mandatory equipage requirements likely to stay the same but be greatly enhanced by cheaper, faster, and lower latency digital connections?

This year, Starlink[3] is offering high-speed, in-flight internet connections with global connectivity. This company is not the only one developing Low Earth Orbit (LEO)[4] satellite communications. There are technical questions to be asked in respect of safety, performance, and interoperability but it’s a good bet that these new services will very capable and what’s more, not so expensive[5].

It’s time for airborne communications to step into the internet age.

NOTE: The author was a part of the EUROCAE/RTCA Special Committee 169 that created Minimum Operational Performance Standards for ATC Two-Way Data Link Communications back in the 1990s.

POST 1: Elon Musk’s Starlink Internet Service Coming to US Airlines; Free WiFi (

POST 2: With the mandate of VDLM2 we evolve at the pace of a snail. Internet Protocol (IP) Data Link may not be suitable for all uses but there’s a lot more that can be done.






Just H

What is the future of Hydrogen in Aviation? Good question. Every futurologist has a place for Hydrogen (H) in their predictions. However, the range of optimistic projections is almost matched by the number of pessimistic ones.

There’s no doubt that aircraft propulsion generated using H as a fuel can be done. There’s a variety of way of doing it but, the fact is, that it can be done. What’s less clear is a whole mass of factors related to economics, safety and security and desirability of having a hydrogen-based society.

H can be a clean form of energy[1], as in its purest form the process of combustion produces only water. We need to note that combustion processes are rarely completely pure.

It’s an abundant element but it prefers to be in company of other elements. Afterall, the planet is awash with H2O. When H is on its own it has no colour, odour, or taste. In low concentrations, we humans could be oblivious to it even though there’s a lot of it in the compounds that make us up.

Number one on the periodic table, it’s a tiny lightweight element that can find all sorts of ways of migrating from A to B. Ironically, that makes it an expensive element to move around in commercially useable quantities. H is often produced far away from where it’s used. For users like aviation, this makes the subject of distribution a fundamental one.

Part of the challenge of moving H around is finding ways of increasing its energy density. So, making it liquid or pumping it as a high-pressure gas are the most economic ways of using it. If this is to be done with a high level of safety and security, then this is not going to come cheap.

There are a lot of pictures of what happens when this goes wrong.  Looking back at the airships of the past there are numerous catastrophic events to reference. More relevantly, there’s the space industry to look at for spectacular failures[2]. A flammable hydrogen–air mixture doesn’t take much to set it off[3]. The upside is that H doesn’t hang around. Compared to other fuels H is likely to disperse quickly. It will not pool on the ground like Kerosene does.

In aviation super strict control procedure and maintenance requirements will certainly be needed. Every joint and connectors will need scrupulous attention. Every physical space where gas can accumulate will need a detection system and/or a fail proof vent.

This is a big new challenge to aircraft airworthiness. The trick is to learn from other industries.

NOTE: The picture. At 13:45 on 1 December 1783, Professor Jacques Charles and the Robert brothers launched a manned balloon in Paris. First manned hydrogen balloon flight was 240 years ago.




High ALT

Normal commercial air traffic control doesn’t go beyond 60,000 ft in altitude. That makes sense since civil flying activities have been limited to lower altitudes. In fact, modern commercial airliners are not designed to fly above about 45,000 feet. This is a compromise based on what works commercially as much as what’s works best. Aircraft instruments are calibrated making standard assumption about the atmosphere.

For some of its flight, Concorde cruised at a height of 60,000 feet. More like a military jet, with its speed it had the capability to make use of higher altitudes.

It’s even possible to fly above 50,000 feet without an engine. The world record glider flight by AIRBUS shows it’s possible.

The Earth’s atmosphere is not uniform. It changes its characteristics with altitude. The atmosphere can be divided into five layers, as the temperature and density change. They are named: Troposphere, Stratosphere Mesosphere, Ionosphere and Exosphere. 

The Troposphere is a layer that goes from 8 kms (26,247 ft) on the poles to about 18 kms (59,055 ft) on the equator. This is the layer where weather is experienced.

On average, the Stratosphere goes up to about 40 kms (131,234 ft). The winds blows fast but they tend to be more consistent as they wrap around the globe. The lower portion of the Stratosphere is virtually isothermal (layer of constant temperature). 

A medieval English philosopher and Franciscan friar, Roger Bacon[1] figured out that the air might support a ship in the same way that water supports ships. In the 13th Century that was a nice academic conclusion but little more.

With all the current controversy surrounding high altitude balloons, that the road to flight started with balloons, could be said to be a bit ironic. It’s long been known about that balloons fly well at high altitudes but it’s a new frontier as far as commercial activity is concerned. For science, weather balloons may go up to 40 km to measure the high level winds.

Some experimental work has been done on trying to commercially use the airspace above normally civil flying. The Google Loon trials[2] are an example of an attempt to float a telecommunications platform high in the sky. These balloon trials were abandoned as difficulties proved greater than anticipated.

It’s not so easy to keep a high altitue balloon on-station.

Now, considering the news in North America, maybe high-altitude operations ought to be a matter of regulatory concern. This is not a subject that any one country can address alone.

There is some legal, regulatory and technical work[3] underway in Europe[4] but it needs to make progress. This is a subject for international collaboration. 






It’s intriguing. Reports of unidentified flying objects being shot down over Alaska, Canada, and Michigan prompts a lot of questions.

The Earth’s atmosphere eventually becomes space at 100 km up. The Kármán line[1] is one way to define the boundary. All aeronautic activities are deemed to take place below that imaginary line. Theodore Karman[2] did his best to determine a height at which the Earth’s atmosphere is too thin to support flight. Now, there’s an international discussion about bringing that boundary down to 80 km. That is the hight above which a person in a space vehicle is said to become an astronaut.

I guess my point is that there’s a lot of the Earth’s atmosphere to continuously monitor, if the task is to know about everything that is flying everywhere. So, it’s perfectly reasonable that reports of unidentified flying objects will crop up, now and then.

It doesn’t mean that there are alien probes popping in to keep an eye on us earthlings. No, in so far as is commonly known there’s no evidence that stands up to scrutiny to definitively prove the existence of sustained airborne craft that are not of this Earth. However, extra-terrestrial objects fall to Earth all the time. Mostly ice and rocks. I wrote about objects falling from the sky in an earlier article.

It’s worth recalling the first article of the Chicago Convention on Sovereignty:  

The contracting States recognize that every State has complete and exclusive sovereignty over the airspace above its territory.

For those monitoring what’s in the air, the primary concern remains about flights over land and populated areas. This is the case where hazards can exist to those below.

All said and done, it’s no time to become alarmed. It may well be the case that these unidentified flying objects were previously ignored. Only now has the militaries in North America been galvanised into action and being more vigilant. The more people look, the more people see.

What do I know? Spy balloon, craft and drones may be much more common than has been generally reported.

Claims and counter claims that everyone is doing it shouldn’t be dismissed out of hand. The technology involved in flying above normal air traffic has a multitude of potential applications. A framework for higher altitude operations is now being written[1].

POST: Diplomatic tensions between the US and China continue to escalate as the US explains its shooting down of high altitude flying objects over North America. Much is still to be uncovered.



[2] A Hungarian American physicist and engineer who was born 11 May 1881.


What do you think are the reasons behind the overall decline in engineering apprenticeship starts in recent years? We are particularly interested in understanding more about supply and demand.

What do you think are the reasons behind the overall decline in engineering apprenticeship starts in recent years? We are particularly interested in understanding more about supply and demand.

Image. It persists even now. In fact, the paper[1] that asks these questions has images of spanner turning. It’s so easy to pick royalty free pictures that pop-up from search engines searches. These images show mechanics in blue overalls. Don’t get me wrong, this is not the least bit disrespectful of spanner turning.

A deep cultural memory persists. It has multiple elements. You could say, in part, industrialisation, still conjures up images of dark satanic mills contrasted with grand country homes of a class of business owners. Basically, dirty, and clean as two key words.

The Victorians did a great deal to both elevate engineering personalities, like Brunel[2], but to hold them as different or apart from the upper middle-class society that the fortunate aspired to join. Those who forged the prosperity of the age had to work hard to be accepted in “society”.

Today, it makes no difference that’s it’s American, popular comedies like “The Big Bang Theory[3]” entertain us immensely but pocket the “nerd” as eccentric, peculiar and unfathomable. I admit this is attractive to a proportion of young people but maybe such shows create exclusivity rather than opening people’s eyes to possibilities.

Having Government Ministers standing=up can calling for Britan to become a version of Silicon Valley doesn’t help. Immediately, that signal is heard from those in authority, young people switch “off”. To boot, the image conquered up is a whole generation out of date. We have the Windows 95 generation telling the iPhone generation what’s the best direction to get to the 2030s.

Here’s a proposition – you must see yourself as an “engineer” to become an engineer. That can be said of a whole myriad of different professions. Each with a common stereotype. Look at it the other way. If you cant’t see yourself as a person who can shape the future, it isn’t likely you will choose engineering.

My observation is that we need to get away from too many images of activities. In other words, this is an engineer at work. This is what they do. This is what they look like. What we need to address is the touchy-feely stuff. Let’s consider how young people feel about the world they have inherited from my generation.

A high level of motivation comes from the wish to make changes and the feeling that it’s possible to make changes. That the skills picked-up as an apprentice will help you shape the future. Engineering is part of making a better world.

[My history is that of an Engineering Industry Training Board (EITB) apprentice who started work in 1976.]





Eyes wide open in astonishment. I saw a supermarket newsstand. That’s not new. From time to time, I find it better to scan the daily headlines rather than buying a newspaper. Frankly, in the world of social media and search engines the sane and sober daily national newspapers are too expensive. They only make sense on a Sunday when there’s time to take in what they have to say.

It’s a moribund marketplace. British daily newspapers are in slow decline. Nevertheless, each title has a readership that remains loyal even if it’s declining in numbers. Before the mobile phone took so much of our attention time it was important to consider who reads the papers. As a sketch from the BBC comedy “Yes, Prime Minister” nicely put it[1].

I have an admiration for those who can transform difficult technical material into everyday language. That kind of communication skill is much needed and often undervalued. Taking simple words and sentences and telling a story that makes knowledge accessible, well that’s rare.

The newspaper headline that caught my eye was “It’s a space burp, Jim, but not as we know it.” Topped by “Earth facing solar blast as powerful as a billion nukes”.

This is wonderful example of how to turn real science into pulp and mush. I might be the only one who picked up the Daily Star, some irony there I think, and thought this thought. What a way to highlight a story about the sun. No, not The Sun but the sun that’s 93 million miles away.

There are some great people in the National Oceanic and Atmospheric Administration in the US who run a space weather prediction centre[2]. Their website is a place to go if you want to know where to see the northern lights at a particular time and place. On Monday 9 January, there was a solar flare that may have affected radio transmissions in South America. That’s useful to know if you are on a ship using High Frequency (HF) radio communications in that part of the world.

“Earth could soon be in the firing line of a massive solar storm with the power of billion hydrogen bombs” is certainly an interesting and rather scary way of putting it. What the readership of The Star should do about this suggested calamity is not explained.

The Sun is restless, powerful, and essential to life on Earth. It’s prudent to keep a watchful eye on what it does. There’s no doubt that it can cause havoc on extremely rare occasions. We are now more vulnerable than past generations given our dependence on extensive electronic communications.

The Sun runs on an 11-year cycle. I don’t think anyone knows why that happens, but it does. We are coming out of the quiet part of the cycle so there’s likely to be more reports on this subject. Solar flares, like massive earthquakes and volcanic eruptions are difficult to predict. Our ability to warn of a once in a 5000-year event is fragile.

Perhaps this story is a hopeful wish of a newspaper editor. We will put down our broken mobile phones and pick-up newsprint once again. I wonder?



Step on the Moon

This coming Wednesday it will be 50-years since the last human footstep was made on our Moon. On 11th December 1972, Apollo 17 arrived on the surface of the Moon. Although 10 Apollo missions were planned to step on our Moon only 6 were made. The last man on the Moon left on 14th December 1972. Eugene Cernan was the astronaut who made that last footprint[1].

This last week, I listened to an online lecture called: “Return to the Moon: “Apollo” for a new generation”. Professor Craig Underwood gave that lecture[2] at Surrey University. He reflected on the success of the Apollo moon landing missions between 1969 and 1972.

Just as he did it gave me cause to reflect on the impact that space adventure had on my boyhood self. Those years from age 9 to 12 must have had a profound impact on not only Eugene Cernan but Professor Underwood and me. We each became electrical engineers.

We became captivated by the unbounded capacity of engineering to change the world around us. It’s true that’s a double-edged sword in that both positive and negative transformations can occur. Notably, we can see that with the current use of airborne drones. On the one hand they can be used to deliver medical supplies on the other hand they can deliver devastation in war.

Here in the UK, we have a lot to thank Gerry Anderson[3] too. The creator of Thunderbirds, Captain Scarlet, Stingray, Joe 90, UFO and Space:1999 had a market impact on both the Professor and me. Colourful fantasy it may have all been, but those stories captured the imagination a generation.

The British TV series UFO and Space:1999 envisioned a permanently stationed Moon base. The leaps of the imagination in the 70s were partly due to the real achievements of the Apollo missions. Maybe it was beyond us to have a working base on the Moon by 1999 but now it’s starting to become a practical possibility.

Today, Sunday, NASA’s Orion capsule arrives home[4]. All being well, the spacecraft will splashdown in the Pacific Ocean after a 3-week trip around the Moon. I wish the project good fortune. 

POST: Sunday 17:40 GMT. The Orion spacecraft, which is to carry astronauts to and from the Moon, has splashed down in the Pacific Ocean after its test flight


[2] The Institution of Engineering & Technology




What’s in an accent? It certainly is a point of discussion. However much we pride ourselves in championing diversity there’s prejudices that have been centuries in the making.

I believe, we all want to see inclusive and welcoming environment in every profession and occupation. I’m opposed to all forms of unfair discrimination especially those of class-based prejudices. In this country, a persons accent can so easily be associated with a region or city. Then all the baggage of history associated with that place can form snap judgements about that person.

It was a while ago but a case in point sticks in my mind. A space project that didn’t go as planned resulted in a probe crash landing on planet Mars. The Beagle 2 project[1] was ambitious however ill fated. The bubbling enthusiasm of the project leader Professor Colin Pillinger from the Open University was infectious. At the same time, it was impossible to miss his West Country accent. It didn’t impede his inspirational promotion of space exploration, but I do remember remarks made about his accent. They were not always complementary.

Now, you might say that was more than a decade ago. We’ve moved on. I don’t think so. The glorious West Country accent, and I include the city of Bristol in that mix, is still associated with a rural Arcadian dream of country life. This much cherished mythology continues to be promoted in English lifestyle magazines and every part of the broadcast media.

It’s a fantasy where educated, philanthropic and sophisticated citizens move from London to enlighten impoverished country folk. Their hope being to soak in the innocence of country ways but, at the same time, offer erudite advice to the backward locals.

If I have an accent it has all but gone. That said, it does broaden when I return to the West Country. There’s a whole series of words which don’t seen quite right said anywhere but in the rolling hills of Somerset and Dorset. Ways of saying things that I grew up with that are meaningless out of context.

Although the association of a rural accent often goes with an unfair characterisation that someone is not too bright, on the plus side it’s linked with friendliness, kindness and warmth. That sounds a bit like a description of a Hobbit. There’s an accidental proof that these prejudices are deeply ingrained in English literature.

I remember early in my career that too much retained from childhood was a barrier to getting a message cross. Slowly but effectively my accent became generic. There’s no doubt this had an upside when it came to technical presentations in front of a mixed audience. Even more important in front of an international audience. It shouldn’t matter but it does.

In a conversation about helicopter safety, a French colleague once lent over to say to me that he knew our Texan partner was speaking English, but he had no idea what he was saying. Is that a case for a standardisation of English – maybe?


Humans in Space

Smart people have strong views on human space flight. In my mind, human space flight isn’t a football for arguments over public verse private. How missions are funded is less important than the fact that they are funded. Space flight will always be a high-risk activity. Those risks will sometimes be borne by the public sector and sometimes by the private sector.

Saying that all we need is robotics in space is to overstate the case for robotics. No doubt, robotics will play a fundamental part in exploration. It’s one component in a bigger picture. Humans need to go to space. That’s a rather a didactic statement. It needs to be challenged. So, my answer has several parts, and here they are:

Firstly, it’s not that we have a choice, given the nature humans have demonstrated over the last million years. Discontent with staying in one place, we are constantly on the move. We’ve inhabited every part of the globe. Even the most inhospitable parts. It’s extremely unlikely we will counter that instinct to travel, to go, and to see for ourselves. First-hand.

Secondly, every robotic mission has limitations based on the design of the machines we send into space. A designer must use the knowledge of their time to anticipate what may be needed, often a decade from the first moment they sat at their computer. The adaptive capability of humans is unmatched. However, machines advance, it will be unmatched for tens of decades ahead.

Thirdly, our lives are full of stories of imaginary flights. From Leonardo da Vinci vivid creativity to the practical achievements of the Wright brothers. Imagination spurred on inventors to bring to life ways in which humans could take to the air. The same applies to space flight. Flash Gordan is a comic book character. We know that Star Trek is a fiction. The film Gravity stressed the dangers of space. None of this detracts from an imbedded predisposition we have for space-based adventures.

Fourthly, when faced with the new it’s not always clear what to do. However, if unprecedented situations arise, we humans rise to the occasion. The inventive capacity of people is unique. When the machinery around us fails we come up with answers. We work out a way to get over the problems. Being able to rapidly fix things matters in space[1].

Fifthly, our species is successful, in part, is because we face risks. It could be said that existence requires us to face risk, but we do it anyway. Our enjoyment of dangerous sports is one indicator. People train to face perils and are thrilled to overcoming challenging circumstances. Collectively we delight in their achievements. Why go to space? – Because it’s there[2].

It’s more than evident that from the perspective we have in the here and now, we can only see so far ahead. A few will see further. What seems obvious to a highly educated commentator on human space flight may be rendered null and void at a stoke come the next discovery.

NOTE 1: On the third point, I found a quote from Orville Wright. “No flying machine will ever fly from New York to Paris. That seems to me to be impossible. What limits flight is the motor.” So, even with his inventiveness and imagination it only went so far. [Early Flight – From Balloons to Biplanes].

NOTE 2: On the fourth point, the experience of my early career working on ground test equipment for communications satellites comes into play. Extensive testing is needed on any space borne systems. As I remember it being said – we don’t make ladders that high.


[2] Why climb a mountain? British climber George Mallory gave a famous response in a New York Times interview in 1923: “Because it’s there.”

Moon Mission

Wishing Artemis well in the plan to go back to the Moon

The universe is big, I mean really big, but our nearest neighbour is close by. Seeing our unique satellite orbit the Earth is as common an experience watching the weather. No need for a telescope.

The circumference of Earth (distance around Earth at the equator) is roughly 40,000 kilometres (25,000 miles). The distance to the Moon is 10 times the circumference of the Earth, or roughly 400,000 kilometres (250,000 miles[1]). That sounds like a lot but compared with the dimensions of our solar system it’s nothing much.

The first humans walked on the Moon on 20th July 1969. I was 9-years old. I watched the event in our living room on a small black and white TV. Around the globe, hundreds of millions of people watched as Armstrong stepped out on the surface of the Moon for the first time[2]. For good or ill, humanity changed on that day.

A plan for returning humans to the Moon is underway[3]. NASA’s new lunar mission is ready for launch. Called “Artemis” a mission is on the launch pad. In ancient Greek mythology, Artemis was heavily identified with Selene, the Moon.

This project will work with industry and international partners, like the European Space Agency (ESA)[4] to send astronauts to the surface of the Moon. The European Service Module (ESM) will provide for future astronauts’ basic needs, such as water, oxygen, nitrogen, temperature control, power, and propulsion.

It’s a big day. Exploration is a part of human DNA. These are the next steps. I wish the project every success.

POST: Well, we get to use that well used phrase – Space is hard. “Space is hard.” But why? — Elizabeth A. Frank (

[1] 225,623 miles away when it’s at its closest. The Moon’s orbit is not a perfect circle. When the Moon is furthest, it’s 252,088 miles away.