Boeing vs Airbus - an unusual (?) design comparison

[Phil Bunch]

An excerpt from a recent article in the Washington Post newspaper.  It compares Boeing and Airbus in a way that I had not seen before.  Does this comparison make sense to others?



In case the above forum URL posting doesn't work, below is the plain text URL:

http://www.washingtonpost.com/wp-dyn/content/article/2009/06/26/AR2009062602863_pf.html



So how do we best design this "man/machine" interface? That's a tricky question, and controversial. Airbus aircraft emphasize the machine, while Boeing planes give pilots more authority. It's a dilemma in the design of all complex systems, and especially those with catastrophic potential. Airbus has an "integrated" architectural philosophy, which is like Nobel laureate Herbert Simon's example of a watchmaker who assembles all the components of the complex watch at once. Boeing, on the other hand, uses a "modular" design, where the watchmaker first assembles a number of modules and then fits them together.

If the first watchmaker is interrupted in his work, the whole thing falls apart and he has to start over again; the second need only start over on the one module he was working on. In integrated systems such as Airbus, an "interruption" can be the failure of speed indicators, excessive turbulence, a short in the coffee machine (it happens and nearly crashed one plane) or a thousand other small wounds that can bring the whole system down. In the modular system there is more of a chance that the "interruption" will only disable one module and that backups and redundancies will be called into play, or that the pilot can use "work-arounds," taking command of the system.

If "interruptions" such as faulty code, hostile environments, intruders or equipment failures are rare and the consequences are not catastrophic, integrated systems are preferable, because they're cheaper to build and will run faster. But if interruptions are not rare, and especially if the consequences of failure can be catastrophic -- e.g. loss of many lives, widespread pollution, cascading destruction of adjacent systems -- then modular systems are preferable.



The author, a sociology professor at Yale, has written two books on accidents and the like, but it doesn't seem that he has technical credentials that would normally be associated with being an expert in such fields except perhaps in psychology and man-machine interactions.

Below is his wikipedia bio and links to his CV:

http://en.wikipedia.org/wiki/Charles_Perrow

Is Boeing a modular design company and Airbus an integrated all-at-once company?  I can't make sense of this assertion from my admittedly limited aviation and avionics background.  I thought everything in a modern large airliner had to be integrated and yet the subsystems have to fail as gracefully and as independently as possible.  While nothing can achieve perfection, they just wouldn't work as I understand this author to describe these airliner designs.

[Hardy Heinlin]

Is Boeing a modular design company and Airbus an integrated all-at-once company?  I can't make sense of this assertion ...

I can't either. Does the author give an example somewhere? Re instruments: As far as my eyes can see, on the Airbus all avionics are modularized, too. And if we're talking about the mechanical parts (fuselage, wings, engines etc.) I would have thought the Airbus is even more modularized than the Boeings: France produces part A, UK part B, Spain C etc.

Cheers,

|-|ardy


Edit:

The author, a sociology professor at Yale, has written two books on accidents and the like, but it doesn't seem that he has technical credentials that would normally be associated with being an expert in such fields except perhaps in psychology and man-machine interactions.

Ah, a sociologist. :-)  I use to take sociological hypotheses always with a pinch of salt ...

Edit 2: I meant to say: with a spoon of salt. Of course, I take any hypothesis with a pinch of salt, also those from non-sociologists :-)

[Jeroen Hoppenbrouwers]

How does the 787 fit this picture?

Also: we recently had a discussion about how "the plane as a whole" could have detected one (1) failing radio altimeter in the recent Schiphol crash, where all other systems worked perfectly.

[Zinger]

I consider myself an authority on accident prevention, my track record is the strongest proof- tens of thousands of sorties in harsh flying conditions under my authority without one casualty or  a single aircraft serious damage. Unparalleled in that environment. At age 21 (1966) as squadron safety officer I submitted a thesis, part of my qualification as captain. I chose the subject-  flight safety in war and peacetime. I developed and presented a concept which raised the examining panel's eyebrows in disbelief, close to disagreement. I challenged the organization's approach. Thirty years later the US armed forces started to implement it, now known as Operational Risk Management (ORM).
To the issues:
The Airbus system design (e.g. flight control system) to me is not suitable for human piloting. First, FBW with a sidestick with limited travel doesn't give the pilot sufficient cues as to control surface status. Can't comment about control feel and feedback since I haven't flown it. Secondly,  the control laws and their failure states and fallbacks are far too complex, and deviate from a natural design.  One could possibly mitigate some of this by extensive and frequent simulator training, but it will remain a major problem. The Boeing concept is the right one.

There are serious flaws in modern cockpit presentation of information to pilots. Nasa. Boeing and science and industry teams are working on it. Suffice to say that out of 19 B747-400 pilots of all experience levels, 18 didn't react to serious display situations presewnted to them such as below glidepath on approach, in a team's test. When you take 3 out of 5 crewmembers out of the cockpit, the remaining two must cope with multiple tasks. Under unfamiliar and stressful situations, the cockpit becomes a trap, resulting in accidents like the Turkish landing months ago at Schiphol, or the German chartered B757 which plunged into the water 2 minutes after takeoff due to one static port blockage (plunge was repeated by 3 more crews replicating the event in simulator during the investigation).

In summariy, the two major contributors to modern aircraft crashes are automation design flaws, and unsuitable personal screening, training and currency checking. Manpower suitability screening and training are now further deteriorating due to the economic crisis.

[Zinger]

A comment about the Turkish Schipol accident. The function of one altimeter is irrelevant even though it may have started a series of events. What is relevant is piloting. Among other things, pilots should identify such problem and correct its implications within a few seconds.

[Mundyas]

Very interesting Opherben about your experience over the years.

As only a sim pilot (with very limited real flying experience with my brother once a PPL ) very aware of my inadequacies and his!!etc. I remember flying with him once from Biggin Hill to Exeter, we got everything sorted flight plans etc. Then ATC said we could fly directly across Gatwick airspace!!!  instead of our planned route (kind of them of course) but for a moment confused us both as had to very quickly re-plan route.

For example there seem so many little traps pilots can fall into through tiredness, boredom etc.

As Mike Ray (retired captain) put it very well I think  "The downside of the -400 operation was the long range mission. Take off is made at incredibly heavy gross weights and the flight plans require that we fly for hours in cruise using automated flight controls and navigation aids ...... only get to land  (manually he means of course) .. once or twice a month"

Andrew