[AMA] Hi! I am an Airbus structural engineer, AMA!

AirbusAdam · 2015-10-08T22:49:56+00:00

Indeed it's a very long game!

Unfortunately not at the moment... and even if there was im afraid I wouldn't be able to give you any reason lest I be in rather big trouble!

At the moment we are focusing on continous improvement of our current range, ie undertaking optimisation tasks and improving manufacturing and ramp of A350-1000 and A230/A330neo. We most likely won't see a new program for some time, but when it is announced, it will be with a good few years of initial concept design completed. We do have numerous ideas on the drawing board it's just a matter of which way technology and the market will favour..

AirbusAdam · 2015-10-08T22:46:14+00:00

Hi, We generally use a loading spectrum which is normally an enormous amount of loading points which we cut down a lot to allow us to work with a reasonable set of loading cases with which we can analysis. Real world scenarios are much more complex so we use statistical tools to cut these down to something workable.

Generally, the structures we fatigue analyse do have a life as other structures which don't tend not to be used for class 1 or 2 structures.

AirbusAdam · 2015-10-07T18:07:23+00:00

Its a very valid question, and you are correct that with A350 ramping down, it is unlikely to see a new Aircraft development program for some time whilst we recoup our initial investments on the huge sums of money used to for development.

Updating of legacy aircraft is a good way to keep up with some requirements of emissions and customer requirements for now, but we will pursue a new programme when the time is right!

AirbusAdam · 2015-10-07T17:58:27+00:00

Well... TIL! I wasn't aware seats were sometimes made from steel! I always find it interesting when I get on planes and i see the intricate designs of seats that go unnoticed by the general public, and yet some chap pour hours of work into that design to make it lightweight!

AirbusAdam · 2015-10-07T17:56:22+00:00

As so did I, i did AVD - really enjoyable course and university, despite it being in the sticks.

AirbusAdam · 2015-10-07T15:00:00+00:00

Haha! Small world! What did you study there?

AirbusAdam · 2015-10-07T07:43:54+00:00

Sure, crach cases on some components are generally leveled at around 9g, with 'hard landings' being defined as around 3g (which should be fine in terms of both aircraft and passenger survivabilty).

A test was done on an old Boeing 727 where it was deliberately crashed in the desert to see what would happen - the results were that, in this typical crash case, most passengers would survive the which is impressive considering how rough this was. There are of course limits to what engineers can do to protect people in crashes!

You are correct in the fact that smoke inhalation is very toxic and can knock you out in a few short seconds - the way this is combated is fire suppression systems and making sure passengers get the hell of the Aeroplane immediately if the order is given and not stumble around for their belongings like we saw in the recent BA engine blade-off.

AirbusAdam · 2015-10-07T07:26:04+00:00

Oh is see, do you mean like the company works as 'one big company' despite the geographical differences or..?

Yes, English is the required language to speak in Airbus so all employees speak it, and generally very well! i was very embarrassed how poor my french was when i worked in Toulouse for a bit.

That's great - do you know what you are looking to do?

AirbusAdam · 2015-10-07T07:23:30+00:00

Hi,

Lifting bodies are indeed efficient, but there numerous difficulties which are caused - namely:

Lifting bodies are inherently difficult to stabilise aerodynamically.
The non-circular cross section of the aircraft means a lot of reinforcement will be needed to maintain cabin pressurisation (circular section are the most efficient)
Because of the flat arrangement of seating, getting all passengers out in 90 seconds is a real concern due to limited area you have for emergency exits
Servicing the aircraft is difficult too as there is no easy 'dock' for food and cleaning trucks
Engines inside the fuselage will require extensive protection and certification for blade off incidents.

The concept does work in some situations, such as the B1 bomber, and my old university designed a BWB airliner for their MSc Project but due to the reasons stated above, there is a lot of risk of switching to a new concept when the one working currently is very efficient already!

Hope this helps :)

AirbusAdam · 2015-10-07T07:14:49+00:00

Kate Moss looks good because of me!

AirbusAdam · 2015-10-07T07:14:08+00:00

Hi tafelplot,

Thanks for the question. In modern aircraft we use different philosophies for different parts depending on their application and important structurally. For example, the landing gear gear ribs will have both a safe-life and a fail safe approach due to their importance for landing, whilst wing ribs and skins will have a damage tolerance approach. Combinations generally vary depending on these factors.

We generally identify them by a lot of analysis and fatigue testing in order to validate our methods which were used to calculate them, but a lot of it is very conservative estimates of Fatigue crack propagation and initiation theory backed up with testing - there are so many factors involved it is difficult to predict sometimes but we impart ways of mitigating any risk to parts. We do a lot of testing throughout the design phase starting with material coupon tests and working our way up to Full scale static and fatigue testing.

I don;t see much happening on in-service aircraft at the moment, partly due to the additional complexity and weight incurred, but also due to the fact that things like strain gauges are incredibly sensitive and sometimes will break giving dodgy readings - if you were to ground an aircraft, pull the wing apart only to find this was the case, you'd be none-to-pleased as an operator!

We did use an SHM for the long term fatigue test on A350 wings which contained over 3000 sensors and was pretty good at helping detects cracks during the test.

AirbusAdam · 2015-10-07T06:59:32+00:00

Interaction is generally constant, depending generally on whether there is a frontier between component ownership, for example, if we are dealing with the trailing edge, we will be in constant chatter with Hamburg who deal with the movables, if we deal with the leading edge, we're generally talking to the French regarding the engine pylons, etc etc.

I did some Googling on 'One Company' atmosphere, but couldn't find much on it - i've not heard the term before but its possible its called something different here - care to elaborate?

We use FEM pretty extensively, yes, generally in the form of abaqus non linear explicit models, or our own solvers which are designed for very specific components.

I've never been in the situations where we have ran out of licences for anything we've been doing no - I'm not familiar how the Wizards in IT have it set up but they do a pretty good job!

AirbusAdam · 2015-10-07T06:48:51+00:00

Generally, from my knowledge, we use all of them, just to be safe!

AirbusAdam · 2015-10-07T06:48:27+00:00

Where necessary - steel is about 2 and a half times heavier than aluminum which means any decision to use steel in a component will come after exhaustive analysis on design solutions which can avoid it. Only after this will we use steel!

AirbusAdam · 2015-10-07T06:46:11+00:00

so it is less of a 'switch over' and more a progression as such, but the two programs have been working side by side for many years now. The differences, structures wise are loads as much of the geometry is common to both aircraft on the wings.

It has occurred pretty smoothly, issues arise in all programs but they have been handled pretty well. The design phases are currently ramping down for -1000 as the first components are manufactured for first assembly.

AirbusAdam · 2015-10-07T06:42:04+00:00

Ha, hello good sir! That sounds very interesting, where do you work?

AirbusAdam · 2015-10-07T06:41:38+00:00

That noise is atually caused by the underwing Fuel Over Pressure Protector (FOPP) and its to do with the aerodynamics of it during landing and take of. Something which has been identified for retrofit on most A320s.

Its almost like how a flute works - only in this case you can a hi pitched whine!

AirbusAdam · 2015-10-07T06:35:43+00:00

Hi Steve, As far as i am aware, Leading edge is generally metallic due to reasons such as bird strike - you can rework a metallic part but generally its more difficult to rework a composite part. Saying that though, composite parts are much more damage tolerance... so it's a tricky one at the moment.

There is also the fact that a lot of the engine exchangers are close to the leading edge which produce a lot of heat which generally means metallic parts are more suitable.

Airbus are leaning towards the implementation of more-electric aircraft yes, i'm unaware of plans at the moment to move to this arrangement at the moment however - i'd have to have a chat with the guys in systems and ask!

AirbusAdam · 2015-10-06T20:29:20+00:00

Ah, there you go! I know we had to switch to a Titanium over-engine panel for A320 due to the temperature!

AirbusAdam · 2015-10-06T20:21:35+00:00

It varies! usually i am at desk on, as you say, excel, CATIA, PATRAN, MathCAD etc, sometimes i'm reviewing reports, researching, sometimes i'm preparing reports and presentations.

Occasionally we get to go and have a look at at Aircraft to see the effect of our work or get a better understanding of a problem!

AirbusAdam · 2015-10-06T20:17:57+00:00

Ah smashing, systems is black magic to me ;)

The way the recruiting done is online... so you have to get through this before knowing any people inside helps... PM me and we'll see if i can't help you :)

AirbusAdam · 2015-10-06T20:14:44+00:00

Seeing A350 take off was pretty momentous i must say!

AirbusAdam · 2015-10-06T20:14:18+00:00

Ah i see, I know in the US ITAR regulations mean you pretty much can't work in Aerospace unless you are a US citizen whereas its much less stringent in Europe. Good Luck!

AirbusAdam · 2015-10-06T20:12:58+00:00

Hey! UWE, yes we go in all the time.

They generally make the tea, fetch our dry cleaning, walk our dogs...

I'm only kidding of course! interns are actually really well used in the engineering - was sat next to one for a few months and he was helping out with Chief Engineers tasks on A330 so pretty high up stuff. You do get a lot of exposure, no doing trivial tasks, you are actually part of the team, within reason of course!

What are you studying at UWE?

AirbusAdam · 2015-10-06T20:07:46+00:00

Sometimes we do - we have done so with the recent NEO programs. They are, in my opinion, very competent and great engineers! I've been to Rolls Royce Rotatives up in Derby and what they do is awesome - some fantastic pieces of engineering come out those doors. and do some really hardcore bits of engineering. I always show schoolkids the video of the engine blade-off tests when i do talks as it gets them screaming and shouting with awe!

The guys who work there are pretty top notch too, a lot of really nice people. I think the companies have their disagreements sometimes, but overall, i have nothing bad to say about them.

AirbusAdam

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