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Size Vs. Safety?  
User currently offlineFerroviarius From Norway, joined Mar 2007, 225 posts, RR: 0
Posted (4 years 1 month 2 days 3 hours ago) and read 4441 times:

Good afternoon,

while, not being French, I nevertheles have a "faible" for certain types of french engineering - no German or Italian or British og Japanese or US car EVER can beat the comfort of a large Citroën with hydropneumatic suspension, the Normandie was faster at 160.000hp than the Queens at over 200.000 just because of intelligent hull engineering, André Chapelon was THE genius in steam locomotive constructions of all times etc. pp. I would, nevertheless, like to discuss a more general question concerning the A380 and future, and potentially even larger, fatties.

It basically seems to be a question of a decade or so until commercial airliners with 1000+ passengers will cruise the skies on a daily basis. HST trains in Japan, France, Germany, Italy ... have capacities by far exceeding anything in the air. Large Ferryboats can take many thousands of travellers on one tour.

I am not informed whether the statistical probability of a fatal accident is in any way related to the size of commercial aircraft. If, in first order approximation, this probablity is independent of the size, then it would be as probable - let's hope it will never happen - that an A380 crashes as it would be that a DASH would.
However, the magnitude of the disaster would be of an entirely different scale in the former case than in the latter.

Questions:

a)
Should the size of any means of transport - ships, HSTs, aircraft, - legally be limited to a maximum number of passengers in order to make sure that one incident will have fatal consequences for a "limited number", "only", of human beings?

b)
Is there any theory or are there any calculations which would estimate, at which size of aircraft the prospective number of fatalities during a given period of time due to air traffic would be minimal?

Thank you, indeed, for your thoughts.

Ferroviarius

14 replies: All unread, jump to last
 
User currently offlineElite From Hong Kong, joined Jun 2006, 2796 posts, RR: 10
Reply 1, posted (4 years 1 month 2 days 3 hours ago) and read 4405 times:

Quoting Ferroviarius (Thread starter):
no German or Italian or British og Japanese or US car EVER can beat the comfort of a large Citroën

I would beg to differ here - and some people at Lexus, Bentley, Rolls Royce, Mercedes Benz etc would like to too, but we'll save that for another topic  
Quoting Ferroviarius (Thread starter):
a)
Should the size of any means of transport - ships, HSTs, aircraft, - legally be limited to a maximum number of passengers in order to make sure that one incident will have fatal consequences for a "limited number", "only", of human beings?

I believe this is already done(?) Each aircraft is tested to ensure that it can safely evacuate the maximum number of passengers. Even in the case of the A380, the average time it would take to evacuate a smaller jet would probably be the same. The engines, of course, would be thoroughly tested, and before it is even built there would be numerous calculations and computer simulations.


User currently offlineUAL747DEN From United States of America, joined Dec 2003, 2392 posts, RR: 11
Reply 2, posted (4 years 1 month 2 days 3 hours ago) and read 4377 times:

Quoting Ferroviarius (Thread starter):
Is there any theory or are there any calculations which would estimate, at which size of aircraft the prospective number of fatalities during a given period of time due to air traffic would be minimal?

Air Traffic fatalities are so rare that I would say the time of day would be statistically insignificant.



Quoting Ferroviarius (Thread starter):
a)
Should the size of any means of transport - ships, HSTs, aircraft, - legally be limited to a maximum number of passengers in order to make sure that one incident will have fatal consequences for a "limited number", "only", of human beings?

NO

Quoting Ferroviarius (Thread starter):
while, not being French, I nevertheles have a "faible" for certain types of french engineering - no German or Italian or British og Japanese or US car EVER can beat the comfort of a large Citroën with hydropneumatic suspension, the Normandie was faster at 160.000hp than the Queens at over 200.000 just because of intelligent hull engineering, André Chapelon was THE genius in steam locomotive constructions of all times etc. pp. I would, nevertheless, like to discuss a more general question concerning the A380 and future, and potentially even larger, fatties.

I would argue that everything you listed here could be built just as good by a US company but none of these products were a commercial success so in the end why would anyone want to build these commercial and therefore financial failures? Boeing could build an aircraft much larger than the A380 but what would be the point if it didn't turn a profit? I would say that Brazil, China, Canada, Japan, Russia, and a bunch of European countries could also build a larger aircraft than the A380 but again there is no reason to do such, not even the A380 is successful. I'm sure your proud of the Concorde too, neat plane but a HUGE failure.



/// UNITED AIRLINES
User currently offlineBurkhard From Germany, joined Nov 2006, 4395 posts, RR: 2
Reply 3, posted (4 years 1 month 2 days 3 hours ago) and read 4345 times:

Of couse one fatal accident of an A380 with let say 660 seat would be a bigger desaster compared to an accident with a B787 with 220 on board. But - to transport the same number of passengers, you need 3 B787 vs 1 A380, and the probability than one out of three B787 has a fatal accident is three times the one of the failure of a single plane, so in first approximation the average toll per year is independent of the size.

How does it come to accidents. There are several sources, let us discuss a few:

Aircraft collisions. Rare, but happen. The likelihood of them to happen is proportinal to the square of the average aircraft density on ground or in the air - In a world of 3000 B787 as only aircraft this would happen 9 times as frequent as in a world with 1000 A380, multiply with the impact and you see in this situation larger aircraft are more favorate. Since in reality near major airport most of them operate amoung 1000 smaller aircraft, this effect would be tiny, but it favors larger aircraft for all operations.

Maintenance errors. Difficult to judge. The bigger plane may be more complex, which increases the risk, but maybe you have better trained specialists which reduces them.

Pilot errors. I expect the best captains to fly the biggest birds, so from this I feel safer on a 747 or 380 than on a CRJ - may be completely wrong.

Extreme weather conditions: Larger planes are less sensitive to it, but again a very small difference between 787 and 380.

So I expect the difference to be tiny, but to favor larger aircraft.


User currently offlineElite From Hong Kong, joined Jun 2006, 2796 posts, RR: 10
Reply 4, posted (4 years 1 month 2 days 2 hours ago) and read 4292 times:

Quoting Burkhard (Reply 3):
So I expect the difference to be tiny, but to favor larger aircraft.

Not to mention the amount of fuel and money that an airline could save by flying a larger aircraft once as opposed to a smaller one several times a day.


User currently offlineBurkhard From Germany, joined Nov 2006, 4395 posts, RR: 2
Reply 5, posted (4 years 1 month 2 days 2 hours ago) and read 4264 times:

Quoting Elite (Reply 4):
Not to mention the amount of fuel and money that an airline could save by flying a larger aircraft once as opposed to a smaller one several times a day.

I do not expect this to go into additional safety investments - but it could be the competitor who runs the less eficient fleet has to make cuts on safety - but this should not be the case.


User currently offlineKappel From Suriname, joined Jul 2005, 3533 posts, RR: 17
Reply 6, posted (4 years 1 month 2 days 2 hours ago) and read 4174 times:

Just look at the safety record of the 744, which is exemplary. Size has no relation to safety in aviation IMHO. Proper maintenence and testing does.


L1011,733,734,73G,738,743,744,752,763,772,77W,DC855,DC863,DC930,DC950,MD11,MD88,306,319,320,321,343,346,ARJ85,CR7,E195
User currently offlineFerroviarius From Norway, joined Mar 2007, 225 posts, RR: 0
Reply 7, posted (4 years 1 month 2 days 1 hour ago) and read 4113 times:

Quoting Elite (Reply 1):
I would beg to differ here - and some people at Lexus, Bentley, Rolls Royce, Mercedes Benz etc would like to too, but we'll save that for another topic

There are facts so clear they need not be discussed.   . Btw. I do neither have a driving license - nor did I ever have any during the 50 years of my life - nor do I own a car.

Quoting Elite (Reply 1):
I believe this is already done(?) Each aircraft is tested to ensure that it can safely evacuate the maximum number of passengers. Even in the case of the A380, the average time it would take to evacuate a smaller jet would probably be the same. The engines, of course, would be thoroughly tested, and before it is even built there would be numerous calculations and computer simulations.

That is right, Elite. I rather meant the, thanks G_d rare, situations where there is no evacuation possible.

Quoting UAL747DEN (Reply 2):
I would argue that everything you listed here could be built just as good by a US company but none of these products were a commercial success so in the end why would anyone want to build these commercial and therefore financial failures?

Well, I do not agree. At the time, no US steam locomotive could match Chapelon's in thermodynamic efficiency. H.C.B. Rogers writes in his Chapelon biography about the large numbers of ALCO produced 141Rs for France that they were like "American Ladies - rough, tough, loud, and did their job to 150%" - in other words: well adapted to this world. But the Chapelon engines were unique in engineering. The S.S. United States matched the Normandie, yes, but it was the next generation of ocean liners. Concerning cars: As a passenger I like the Lincoln Town Car (nearly) as much as the Citroën C6.

Best wishes,

Ferroviarius


User currently offlineastuteman From United Kingdom, joined Jan 2005, 10002 posts, RR: 96
Reply 8, posted (4 years 1 month 2 days 1 hour ago) and read 4041 times:
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Quoting Ferroviarius (Thread starter):
the Normandie was faster at 160.000hp than the Queens at over 200.000 just because of intelligent hull engineering,

Always best to get you're facts right when making claims like that, my friend.

Both of the queens shared the same 160 000 shp of the Normandie.
The Queen Mary, when launched, was indeed a fraction slower than the Normandie, but this was, in fact, attributable to a sub-optimisation of it's initial propeller configuration. When new propellers were fitted, she matched the speed of the Normandie.   
Same size, same power, = same speed, surprise surprise  
(p.s. the pair traded the Blue Riband a number of times between 1936 and WW2 to make the point)

As it happens, as a qualified Naval Architect, I share your admiration for French Naval Architecture. They certainly learned how to spell "Metacentre" long before "we" did.
Didn't seem to bother Nelson much mind you, but there you go  
Quoting Elite (Reply 1):
I would beg to differ here - and some people at Lexus, Bentley, Rolls Royce, Mercedes Benz etc would like to too, but we'll save that for another topic

Indeed, the opening sentence almost guarantees some interesting discussion other than those contained in the thread title...  
Quoting UAL747DEN (Reply 2):
I would argue that everything you listed here could be built just as good by a US company but none of these products were a commercial success

The QM, QE, locomotives, Lexus, Bentley, Rolls Royce, Mercedes Benz etc aren't, or weren't financial successes?   

Quoting Burkhard (Reply 3):
So I expect the difference to be tiny, but to favor larger aircraft.

On topic, it would be interesting to know if the presence of the most experienced skippers on the big birds makes a difference.
Adding to your list, I'd suggest that the biggest planes are the most likely to spend the majority of their lives in the hands of "quality" airlines that might pay the best attention to maintenance, parts etc through life.

It would seem likely therefore that the biggest planes might well be the safest, but not because of the plane itself..

Rgds


User currently offlineFerroviarius From Norway, joined Mar 2007, 225 posts, RR: 0
Reply 9, posted (4 years 1 month 2 days ago) and read 3997 times:

Quoting astuteman (Reply 8):
Both of the queens shared the same 160 000 shp of the Normandie.

Thanks you, astuteman.
I - possibly - stand corrected. But as far as I recall from a number of books - which, again, might be wrong - the installed power on the Queens was slightly larger than 200,000 hp of which approx. 160,000 went to the shafts, while the totally installed power on the Normandie was 160,000 hp (of which some 10000s less, I do not recall the exact number by heart, and have the books at home, where I am not right now went to the shaft). I will have to check my sources, it seems.




Quoting astuteman (Reply 8):
As it happens, as a qualified Naval Architect, I share your admiration for French Naval Architecture. They certainly learned how to spell "Metacentre" long before "we" did.

Let alone the Swedes, their arguably most important King of all times personally ordering the "Wasa" to be built with a metacentre above the water line....


Best wishes,

Ferroviarius


User currently offlinespacecadet From United States of America, joined Sep 2001, 3624 posts, RR: 12
Reply 10, posted (4 years 1 month 1 day 21 hours ago) and read 3758 times:

Quoting Kappel (Reply 6):
Just look at the safety record of the 744, which is exemplary.

The safety record of pretty much all modern airliners is such that you could get on any one and not really worry about it.

But compared to other airliners, the 747's general hull loss rate is higher. The 744's is about the same as other airliners, meaning lower than previous-gen models, but it took Boeing about 30 years worth of tweaks to the design of the plane, its cockpit, and its procedures to get it to that point.

There is a learning curve any time you dramatically scale up in size. Nobody had ever made a plane as big as the 747 before and there were some unexpected issues, both with the way the plane handled and with the way pilots reacted to it - they weren't used to such a big plane either. And there were some design issues too - nobody ever really considered that it might not be a good idea to have exposed wiring running through the center fuel tank, for example. Some of these issues (like that particular one) didn't manifest themselves until years after the 747 first flew.

Consider the fact that 49 747's of various types have crashed or been otherwise damaged enough to be written off over the years. 49 out of 1418 built. That's one out of every 30 planes. And this is considered a safe aircraft (and I don't argue that).

It's inevitable that an A380 is going to crash at some point. Flying is getting safer but the A380 is another dramatic scale up in size, and an all new design, with all the unexpected issues that's going to bring. Not all of these are going to be identified and solved during the certification process. Some of them we aren't even going to discover until they lead to an accident.



I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
User currently offlineastuteman From United Kingdom, joined Jan 2005, 10002 posts, RR: 96
Reply 11, posted (4 years 1 month 1 day 20 hours ago) and read 3721 times:
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Quoting Ferroviarius (Reply 9):
while the totally installed power on the Normandie was 160,000 hp

Installed power in Normadie was 200 000 hp

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

Quoting Ferroviarius (Reply 9):
Let alone the Swedes, their arguably most important King of all times personally ordering the "Wasa" to be built with a metacentre above the water line....

Metacentre almost always is above the waterline. The problem with the Wasa was it's metacentre was too low for a sailing ship..

http://en.wikipedia.org/wiki/Metacentre#Metacenter

But we digress...  
Apologies

Rgds


User currently offlineViscount724 From Switzerland, joined Oct 2006, 25125 posts, RR: 22
Reply 12, posted (4 years 1 month 1 day 18 hours ago) and read 3533 times:

Quoting Burkhard (Reply 3):
I expect the best captains to fly the biggest birds, so from this I feel safer on a 747 or 380 than on a CRJ - may be completely wrong.

I have the opposite view. While I always feel safe when flying, pilots flying the CRJs and other shorthaul regional types are probably making 4 or 5 (or more) takeoffs and landings a day, operating to all types of airports in all kinds of weather. The senior captain flying a longhaul widebody may only make 2 or 3 takeoffs and landings a month. And the aircraft they're flying and the airports they're using generally have more automated systems.


User currently offlinespacecadet From United States of America, joined Sep 2001, 3624 posts, RR: 12
Reply 13, posted (4 years 1 month 1 day 17 hours ago) and read 3472 times:

Quoting Viscount724 (Reply 12):
The senior captain flying a longhaul widebody may only make 2 or 3 takeoffs and landings a month. And the aircraft they're flying and the airports they're using generally have more automated systems.

But they generally have many years more experience, which counts more than anything. A pilot making 4-5 cycles per day still might only have 400 or 500 cycles under his belt by the time you fly on his/her CRJ, whereas a pilot flying a 747 on a prestige route probably has many thousands, even if he's only doing 2 or 3 a month by that point. The 747 pilot's more likely to have already seen and dealt with any situation that could be thrown at him.

This is not a hard and fast rule, of course, but as we saw in the Colgan Air accident, regional pilots are often at the bottom rung of the food chain, not very experienced and at least in that case, not even very good. I'd still much rather fly with somebody who's got some years under their belt and who's worked their way up to the top even as lesser pilots have either been stuck flying regionals or been weeded out completely.



I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
User currently offlineFerroviarius From Norway, joined Mar 2007, 225 posts, RR: 0
Reply 14, posted (4 years 1 month 18 hours ago) and read 1507 times:

Quoting astuteman (Reply 11):
Installed power in Normadie was 200 000 hp

Hi, again, astuteman,

I've checked my books and there are, indeed, different numbers in different books. What I had written earlier, 200000 installed hp on the Queens vs. 160000 on the Normandie, I seemingly had in mind from what today would be called a "tech book for little boys", which I had read in the late sixties at the age of nine or ten. But I must deems this source, indeed, as un-reliable compared to other, and more "serious" books confirming your numbers.

Best,

Ferroviarius


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