Complexity and perspective
 

I produced these for the course notes for some teaching I'm doing - I thought it was worth sharing.

https://scontent-b-lhr.xx.fbcdn.net/...b2&oe=54E2ABF6

https://scontent-b-lhr.xx.fbcdn.net/...ea&oe=54DE4248

G

Thanks G

Very interesting.

Although not I think surprising.

Any certificating agency found at fault in executing its duties re a microlight (say) is not at the same risk to legal action from all those who died as a result when compared to the same thing with a double decker wide body that happened to hit the GPO Tower that then laid down along a busy street.

JF

I mostly put it together to show my students that there's a steady increase in regulatory burden with the number of people you can kill in one go, so as you said, unsurprising.

On the other hand, a fair question is that given that a microlight exposes 1/800th of the number of passengers to risk, and has around 1/1000th of the mass, but has 1/16th of the amount of verbage to wade through in demonstration standard compliance - is the microlight being over-regulated?

On the other hand, how many words do you need to say "make sure that the wings don't fall off", whether it's a microlight or an A380?

It was an interesting exercise - I've not attempted to do more than fairly portray the evidence, but it creates some interesting debating points.

G

We would probably get broadly similar curves if we plotted the number of words in the regulations against many other factors. Examples might include number of aircraft flying, size of the aviation industry, value of the world aviation industry, engine fuel efficiency, navigation system accuracy, number of semiconductors in a microchip, or even the amount of money wasted by the EU.

Surely the more important factor is to determine what if any is the link between the two trends. The very act of plotting number of words against MTOW or number of seats may lead some people to think that there is a direct link between the two.

There is isn't there?

The size and complexity of an aeroplane increases the number of people it can potentially kill in a go. Given that, you would expect the powers that be to expect more aspects of the aeroplane to be checked as part of the airworthiness approval process, and in more detail.

That surely is as it should be. Any questions are over proportion - does the complexity of the certification process increase at the right rate, too much, not enough? Or, conversely, if we start at part 25 aeroplanes and go down, does the complexity of the certification process simplify enough as we go down to lighter weight aeroplanes ? Or too much?

G

You appear to have convinced yourself that the increase in words in the regulations has been brought about by the increase in passenger numbers. I would suggest that a far greater factor has been the increasing complexity of the aircraft and aircraft operations.

Over the years a good many additions to the regulations have been brought about either by accidents or by the introduction of new technologies. Concorde didn't bring an increase in passenger numbers, but I suspect that it brought about some additional regulations. Fly-by-wire didn't increase passenger numbers, but it probably brought about some new regulations. Spaceship II will undoubtedly result in some additional regulations, but it won't carry very many passengers.

It's all of the above certainly - but historically pax numbers has always been a major player in defining which, and how complex, a standard is applied.

So is powerplant number and type, and stall speed - there's many ways I could plot it, and I might yet play around with some more variations.

G

The point which I was attempting to make earlier is that simply plotting the number of words against the number of PAX doesn't really prove anything, but it will convince some people that there is a direct link between the two.

If we were to look at how many new regulations relating specifically to PAX numbers were introduced when we went from the B747 to the A380 I suspect that we would find very few. But if we were to carry out the same exercise for the introduction of Autoland or Fly-by-wire I suspect that we would find a many more.

I think the complexity comes in with Part 25 and to a lesser extent, Part 135 and/or 121 Operations and "turbo-jet" power. So there probably is little or no difference in regulations between a Regional Jet or a FBW Biz jet and an A380. Additionally the complexity of regulations will also increase with how recent the design is - for example, you now have to certify Autopilot operation in Icing, which did not apply before.

But.... Also look at the number of topics. the microlight design standards are not including passages dealing with pressurization, hydraulics, autoflight etc., etc. etc. You should have seen the 11 month regulatory fuss when I tried to merge part 23 oxygen systems to approve an oxygen system into a part 27 helicopters - which standard has no reference to oxygen systems.

Look at the emergency exit design requirements for a microlight, then compare them to a part 25 jet. Lots of part 25 words that are not the least needed nor applicable to the microlight.

Interesting though project though, yes, how many people in the headlines....

Very interesting G thanks.

Just in case the apparent size of CS23 puts-off people, I was pleasantly surprised when I had to do a Methods of Compliance check for a project for a single-engine sub-1000 kg aeroplane with fixed landing gear to see how much of CS23 is simply marked not applicable at that level. If you only want to do VMC or do your IMC on traditional gauges it gets even simpler. I'm not saying it's easy, it most definitely is not but it is not as bad as people think.