How High Can You Fly?

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The future is nearer and higher than you might think

Aviation is reaching new heights

In March 2023, EASA published a ‘Roadmap on Higher Airspace Operations (HAO)’ and it is quite an interesting read.

For those of you who think it might be an interesting read, but not interesting enough to read all 55 pages on it, here are some of the highlights (Get it? High lights…)

Our Atmosphere is…

First up, a mini science lesson.

We live (and fly) within the Troposphere which starts at the surface and heads on up to somewhere between 8 and 14.5km. This where weather is as well (except for space weather).

Above this is the Stratosphere which stretches to 50km (and contains the Ozone Layer), then the Mesophere which reaches 85km (and is where we generally see meteors burning up). Above that, and all the way up to 600km is the Thermosphere (where we put our satellites) and then the Ionosphere (the bit which makes radio communications possible because they bounce off it). The final bit of our atmosphere is the Exosphere which stops around at 10,000km.

In case you can’t picture that, its actually less than, say, New York to Sydney (15,979km)

Higher Airspace talks about everything above FL550. A region which most of us have probably mostly thought of as ‘space’ up until reading that mini science lesson anyway.

A quick lesson in work politics.

Sovereign airspace is not really defined. Some say forever and ever upwards (or outwards to be more accurate) from the point on land. Some say about 30 km, which is about as high as some aircraft and balloons currently fly, and some say to about 160km which is where short-term stable orbits exist from.

Highlight #1

Operations above FL550 are likely to happen soon.

Technically they already have with the launch of Virgin Orbiter, and in fact any space travelling device to the moon or the ISS. Which means, there are some things – like whose laws apply up there that we probably should already have covered.

The reason EASA is asking the question (and a whole load more) now is because the Virgin Orbiter, and a whole load of possible future plans, mean military and civilian, “lower level” and higher altitude operations are starting to ‘get in each others way’ more and more.

Highlight #2

What else flies that high?

Not many civilian aircraft do right now, but with innovations in supersonic and hypersonic aircraft design, there is a chance they may start to in the not too distant future/realms of reality. Aside from that, we do currently have a number of things like HAPS (High Altitude PLatform Systems) and ‘Pseudo’ Satellites, rockets and balloony things which already do (pg5 – Intro).

Concorde’s service ceiling was 60,000′ (FL600)

Of course, the issue is not just in regulating the aircraft once in Higher Altitude airspace, but also in how they get to and from say higher altitudes, because that generally involves them heading through not higher altitude airspace where a whole load of other aircraft already are.

Highlight #3

Why do we want to fly up there anyway?

Well, because it has:

  • Environmental benefits (possibly, although the adverse impacts have not really been studied yet)
  • Cost benefits – less weather (of the standard kind) and potentially less need for fossil fuels (once up there) means its potentially cheaper

And also becaus:

  • Technology is just advancing and we can, so we probably will.

Highlight #4

It means more ‘stakeholders’ to consider

We currently have some quite nice boundaries between countries, and also industries, and by that I mean civilian aviation, military people and space folk. We know who rules what and we try not to get in each other’s way.

But if everything starts encroaching on the turf of others, then it starts to get messy for a whole number of reasons. Current ‘mess’ already occurs when rockets are launched (debris falls into areas that aircraft fly in), military test stuff (like GPS jamming) and accidentally jam civilian aircraft systems, military exercises take place which get in the way of civilian tracks…

With the current mingling of missions civilian ops do seem to come of worse most of the time actually, so maybe we should just give EASA and civil authorities control? But even if we did, it doesn’t solve a whole different load of questions like:

  • Who is in charge of airspace?
  • Who is going to decide new regulations?
  • Who is going to enforce that with other people if they don’t agree?
  • Has anyone thought about environmental impact?
  • Who is going to authorise new types and their airworthiness?
  • Who is going to even define what an HAO vehicle is?
  • Who is going to monitor safety?
  • How will you separate traffic up there, and what equipment is even required for that?
  • Do altimeters still work the same?
  • What regulations and rights do passengers fall under?
  • Will pilots need different training?
  • Will pilots need different medicals?
  • Radiation.
  • How will the military and civilian worlds collaborate?
  • Will you have ANS/ATM up there?
  • Does the ‘weather’ up there pose different issues with communications?
  • More stuff
  • Other questions
  • Different considerations…

Highlight #5

What EASA want.

EASA do go on to list some policy ideas (pg39) which rather amusingly begins with ‘Option 0 – Do Nothing’ (amusing because they’re rather established this as not a credible option already)

Ultimately, the Roadmap is a suggestion aimed at galvanising ICAO and hopefully other State’s and their authorities into action so that we don’t end up with a Wild West in Space and answer some of the questions a little more proactively.

So, a global discussion on HAO does seem rather important and hopefully this will encourage those who need to, to!


EASA’s HAO page where you can download the 55 page roadmap

A 2018 paper from ICAO when they looked at industry views on operations above FL600

A different paper from ICAO, published in 2022, looking at Higher Airspace Operations

An informational briefing from the FAA on NAS integration of transiting and higher airspace operations (NITRO)

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