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LHS - its very simple - are all possible safety features installed on aeroplanes regardless of cost of developing and installing them?
Or only the features the regulators deem essential?
Or something inbetween?
I think you (LHS) are taking the debate personally and from my perspective there is no need. We all have parameters we work within and they compromise our lofty ideals. I'm not suggesting your are somehow remiss in not going above and beyond the requirements you work within or are responsible for the cost/benefit trade off.
Ii is very likely, we have very little individual influence over the requirements set out by the Airworthiness bods and we have to assume, they are doing what is required on our behalf.
However, to assume the industry meets those requirements and goes beyond them for anything other than bottom line is really not very likely.
LHS - its very simple - are all possible safety features installed on aeroplanes regardless of cost of developing and installing them?
On new aircraft designs, yes all necessary safety features are intalled.
Thats not what I asked - all [i][b]possible[/b][/i] not all necessary - necessary means that someone made a value judgement
Or do we take it that toys is correct? Not all[i] possible[/i] are installed only those deemed [i]necessary[/i]
Not all possible are installed only those deemed necessary
Damn, he distil's me down to one line.
That is exactly it, necessary yes - a value judgement is made about what is necessary, other safety systems could be installed but if they don't meet the value judgement then they are not in.
Only those deemed neccesary by the Airworthyness bods who are a Govt dept? Presumably if they came up with a whacky new idea that all Brit registered/manufactured (OK, part manufactured) aircraft needed something that would make them uncompetitive, would they be subject to lobbying/political pressure?
You can't install all possible safety features into one aircraft as there would be contradicting performance, duplicated features or not enough space to house it all.
All necessary features means that all bases are covered, there is no design element where a failure would lead to a catastrophic event.
a value judgement is made about what is necessary
no, a safety judgement is made
The air worthieness authourity is that for where the aircraft is manufactured, so inventing some whacky new laws would not be in there interest.
But isn't airworthiness administered by the CAA - a quango? My point was their output may be influenced by elements that are not neccesarily in line with the best engineering solutions...
I'm pretty clear that business builds planes (that it can sell) to quango safety requirements. Quango's are open to influence from all sorts of external forces, many with 'interests' in how competitive the industry is.
Nothing is as simple as a pure engineering solution.....
You have CAA, FAA, TC, ANAC..... so no, they are independent.
If you look at the board of the CAA you will quite a few political appointments [url= http://www.caa.co.uk/default.aspx?catid=286&pagetype=90&pageid=796 ]clicky[/url]
Yep, there some very talented people who work around the world.
All necessary features means that all bases are covered, there is no design element where a failure would lead to a catastrophic event.
Since planes still fall out of the sky occasionally then it implies that for some reason (cost perchance?) A potential, non necessary but desirable feature has been omitted, no?
Since planes still fall out of the sky occasionally then it implies that for some reason(cost perchance?) A potential, non necessary but desirable feature has been omitted, no?
Really? Do you have an example? Must have missed all those catastrophic design failures and all the planes falling out of the sky!
How many aircraft are in the sky at any given time during the day? 20,000? How many flights are there each day around the world? 50,000?
How many accidents are there each day due to a safety feature on a plane?
It is often as a result of a series of unforseen events coming together in an unexpected/unprecedented way causing an, errrm, problem. I think they liken it to the holes in swiss cheese all lining up.
twa 800 was caused by chafing of wire that was routed through a fuel tank, it caused a spark, there was spark suppression system available but it was, at the time too expensive to install versus the likelyhood of it happening. ( I think it was nitrogen inerting)
There are many other examples.
I know it's military but Nimrod is a very good example. One exploded killing all on board even though they were aware of leaking fuel and had decided against fire suppression systems as used by the Septics (on cost grounds).
twa 800 was caused by chafing of wire that was routed through a fuel tank, it caused a spark, there was spark suppression system available but it was, at the time too expensive to install versus the likelyhood of it happening
Is one hypothesis. I believe the official conclusion to the investigation was:
An] explosion of the center wing fuel tank (CWT), resulting from ignition of the inflammable fuel/air mixture in the tank. The source of ignition energy for the explosion could not be determined with certainty. Theories range from a missile, bomb or short circuit.
The benefit is that there was a lot of research done into nitrogen inerting systems and revised lightning protection systems which were then incorporated into new aircraft designs.
I know it's military
Yes, its military, very different.
In 2009 Boeing advised the FAA that its new 787 Dreamliner could not meet the new safety standards. The FAA proposed to relax the safeguards for preventing sparks inside the fuel tank, calling them "impractical."
[url= http://seattletimes.nwsource.com/html/boeingaerospace/2008719843_lightning08.html?syndication=rss ]clicky[/url]
Why was this impractical? COST, otherwise it would be called impossible not impractical.
The NTSB investigation ended with the adoption of its final report on August 23, 2000. In it the Board determined that the probable cause of the TWA 800 accident was:
[An] explosion of the center wing fuel tank (CWT), resulting from ignition of the inflammable fuel/air mixture in the tank. The source of ignition energy for the explosion could not be determined with certainty, but, of the sources evaluated by the investigation, the most likely was a short circuit outside of the CWT that allowed excessive voltage to enter it through electrical wiring associated with the fuel quantity indication system.In addition to the probable cause, the NTSB found the following contributing factors to the accident:
The design and certification concept that fuel tank explosions could be prevented solely by precluding all ignition sources
The certification of the Boeing 747 with heat sources located beneath the CWT with no means to reduce the heat transferred into the CWT or to render the fuel tank vapor non-combustible.
LHS that is the most blatant case of selective quoting I have ever seen, the complete quote is above. Can any cause be completely proven? No. To use your phraseology, If you you had much experience in engineering or science you would know of a thing called occams razor.
Why was this impractical? COST, otherwise it would be called impossible not impractical.
Improved technology of the lighting protection within fuel pipes (this is improved even further now with the introduction of CFRP fuel pipes), and on 787 they introduced a very expensive inerting system to their fuel tanks based on advice. This would have added a huge amount of cost to the design and weight which would have to be mitigated elsewhere, so no, cost would not have come into it.
toys, you seem to be getting quite angry so I think as per my previous post we should agree to disagree on this.
The Ford Pinto Case was perhaps the most notorious instance when a manufactuer calculated the value of loss of life and determined that it was more cost effective to pay for loss of lives rather than implement additional safety measures.
http://www.wfu.edu/~palmitar/Law&Valuation/Papers/1999/Leggett-pinto.html
This would have added a huge amount of cost to the design and weight which would have to be mitigated elsewhere, so no, cost would not have come into it.
Umm you said huge cost, and weight. Weight in the airline industry (you would know if you worked in the airline industry) always ends up with cost, more fuel essentially.
with the twa800 (iirc) the issue was actually the weight of the current suppression system proposed, it added too much cost to flying the plane, in extra fuel and reduced passenger capacity.
toys, you seem to be getting quite angry so I think as per my previous post we should agree to disagree on this
Don't be silly this isn't anger, how can you tell from my typing? No no I am enjoying this. Please don't back out now we are so close to you admitting you are wrong.
Umm you said huge cost, and weight in the airline industry (you would know if you worked in the airline industry) always ends up with cost, more fuel essentially.
This doesn't make sense.
Please don't back out now we are so close to you admitting you are wrong.
Ah, very good, nice try but I won't rise.
Out of probably 50,000 flights each day for arguments sake the last 20 years (how many hundred million flights is that?) you have quoted one incident which had no firm conclusion as to the cause of failure and certainly NO evidence of cost being put before safety.
You said you were clever?
I think you misunderstand me, saying 1 out of 365million flights doesn't matter, I'm not trying to say planes are not safe. I'm just pointing out the widely recognised fact that human lives are measured in cost by the airline industry (and pretty much all industry).
Surely the introduction of ejection seats for all passengers would lead to an increase in passenger survival in certain circumstances? The cost, complexity and reduction in payload would of course be immense, but if the industry was doing all it could to ensure passenger safety.....
A slightly ludicrous and extreme example, but proof that the industry is subject to cba's. 🙂
indeed, or parachutes for everyone..
LHS find me an NTSB report that does not end with "The board finds that the PROBABLE cause was...."
Only 4% of aircraft accidents occur during cruise, so seems a bit pointless spending significant time and money addressing this before tackling other areas - CFIT etc.
The modern Airbus is an intrinsically safe aeroplane through the nature of the fly-by-wire. Modern technology builds on this with EGPWS, better weather radar, PRNAV approaches, and systems such as Honeywell's SmartRunway and EADS' own Brake to Vacate.
Ultimately no amount of technology can protect against poor training, bad judgement, fatigue, and lack of cooperation between the crew, and consequently accidents will continue.
Most new pilots on the A320, for example, have less than 200 hours total time and just 6 landings outside the simulator before carrying passengers - this in itself is not unsafe (it's been like this for many years) but is a factor.
I think the debate is/was about whether the costs of additional safety/functionality is considered during aircraft design (once mandatory minimums are achieved). Obviously this may be extended to crew training which is what the above point is about. Obviously crews could fly with more hours/cycles etc but that costs more....
My personal opinion is that the investment should be made in crew training, instead of adding redundant redundancy at the design stage. You can't really make aeroplanes any safer than they already are with current technology.
The whole keep-a-dog-in-the-cockpit idea is nice in principle, but us 'uman beans can still outfly the computer in most situations, and the autopilot on the Airbus does its best to kill you on a fairly regular basis.
I hadn't precluded training, as it's obvious that it's as important if not more important than technology as a safety measure. It was assumed by others that I was only talking about hardware issues.. Either way I'll bet it's subject to a cost benefit analysis...
My personal opinion is that the investment should be made in crew training, instead of adding redundant redundancy at the design stage. You can't really make aeroplanes any safer than they already are with current technology.
Agreed, 99.999999% of all accidents are human error. Modern designs are building in functions to stop the pilot performing safety hazardous operations in certain circumstances.