If you try to store an enourmous amount of energy, this has always been a safety issue (for example: Rocket science). And although I am always among those first blaming management if something goes wrong ;) engineering is relevant as well. So we need safe battery design and safe battery management. As in real life, larger units are harder to manage. And it always helps if management is well informed about what is going on... Having 8 huge cells (of 3 hidden units each) with only 8 voltage sensing and only 2 temperature sensing devices might not help management to do a propper job... So first we need to make sure that management understands what it manages, has all informations how the units perform and has to be smart to make them produce optimum performance with a perfect safety record. This might be rocket science, but it has been done before. And if something is "too big to manage", split it into smaller units until you can manage them well and accept a few underperformers in your team...

replying Volume
 

IMHO, Volume, you are mixing up here the phantastic progress in microelectronics (and its associated power consumption) with the quite limited one in battery technology.
Indeed, the typical Ni-Cad of the early 80ties (I remember some from the sixties) had 60 Wh or so per Kg. The numbers of the 1990ties NiMH are 110, and 160 are the one's of present Li-ion. See what I mean: barely a factor 3 in 30 years (arguably up to a factor of 5, if you totally disregard price).
A propos price: I considered to replace two 105 Ah 12V lead acid batteries (worth 2 x 150€ in my boat, however my shipchandler prizes 2499 € for the 24 V 104 Ah Lithium Battery that weighs indeed 40 kg less, of interest for
racing, sure, but way too expensive.

In conclusion, I fear that the opinion expressed in my initial post may well be valid.

Volume:There is ALWAYS risk to be considered; it's engineering's job to IDENTIFY risks of a particular design, and suggest risk abatement, but MANAGEMENT must comprehend this and provide direction. Take too little risk, and your aeroplane will obsolete itself quickly; too much risk, and it may never get anywhere. There are plenty examples of both extremes. You gotta push the envelope, but not TOO much.

Ironically, in the mid-late-60s, airline managements perceived a marketing risk in buying a 3-engine airplane for transoceanic routes. Would SLF ever accept a plane with less than 4 engines? Of course, 5 decades of experience taught us this is a total non-issue.

5 decades of experience taught us this is a total non-issue
 

The trans-oceanic two engines failure could happen tomorrow. We've just been fortunate so far.

Not just identify, but quantify. And asses the impact of the abatement. When it comes down to basics, the only common denominator for risk/impact assessment is cost. Something Boeing was adverse to let engineers deal with*.

The other factor is understanding the fundamentals of the risk. In the words of Donald Rumsfelt, there are known unknowns and there are unknown unknowns. Boeing is adverse to admitting when they don't understand something. Their position being that they (and not the FAA/NTSB) are the sole authorities on the technologies, nobody else is in a position to second guess their choices. This is why we don't get an, "Oh crap! We should have used NiCads."

*In this case, I have to give McDonnell Douglas kudos. When Stonecipher came on board, he pushed for more cost visibility on the part of engineering. Heritage Boeing people pushed back.

What?? It's happened already

Ex Cargo Clown,
 

If we think about the same incident in early 2000's there has nothing to do with the number of engines rather than mistakes happend during maintenance.


And one can argue about that, the incident I am talking about has double the chances to occur on a 4 engine aircraft.


Rwy in Sight

Double engine failure hours from land
 

It's understood we're talking about two engines failing due to independent causes.
There's a calculated probabilty that this will happen one day. It's not, as barit would like, a non-issue.
If it does happen, and 300 people are killed, it won't mean that aviation has suddenly become less safe.
.

I see Birdseed Airways has ordered more of these things! Maybe theres an even bigger discount these days.

I guess it is for that very reason why we carry life jackets on board.


Golf-Sierra

Obviously WW is still pushing the Boeing Always button.
Link BA agrees deal to buy 18 Boeing aeroplanes | Mail Online
Regards, Den

Or a jet could be struck by an asteroid. (TW800??)

A spark from a nicked or worn wire to an in-tank fuel gage occurred in the fuel-air mixture space over the fuel surface in a main fuel tank. At that moment this mixture happened to be explosive. By that I mean it more detonated, rather than burned.

Maybe 15 years before I was working on av fuel facilities. One day I idly opened a fuel manual for the different grades and types, say ten in all. Every one had a narrow band of a low percent of fuel vapor in the air that was explosive. Not so below that concentration, nor above. In winter you could be below that concentration in many cases. On a hot summer day it was a different story. You'd be above the the concentration on the ground there (MSL+30'), and a cruise altitude you'd be below the explosive concentration.

In those days, the military inerted that space with nitrogen. Civil aviation used sand-- they buried their heads in it. I recall thinking this was an accident waiting to happen. Fifteen years lateer, TWA 800 was in a climbout in the twilight of a summer day, I believe.

Asteroid? Are you kidding? You must be.:) OE

BA have order more 787s because they are fantastic aircraft.

The fuel savings, engineering monitoring functions and passenger comfort make this an easy choice for them. The battery issue is nearly fixed, why are all the 'experts' on here convinced it's a terrible aircraft? Looks like they know more than all the airlines ordering it. I know some of you are knocking the aircraft because you have an EADS connection or are anti Boeing for whatever reason, but some of the hype and nonsense on this thread is tabloid stuff.

Pilots love the 787, engineers (working with it) think it's great. It's the kind of aircraft operators have wished for. To sit in an operations office knowing what EICAS messages and what parts need to be available for it when it lands is an amazing capability. As a pilot it's a joy to fly.

Until the batteries start smoking!

[quote engineers (working with it) think it's great][/quote]

Well, I don't know what you're smoking, but plenty of more qualified men than you or I, aren't saying that....take off the rose-tinted spec's, supress your national pride and read both the 787 threads all the way through......you STILL in denial?

[quoteAs a pilot it's a joy to fly.][/quote]

No doubt, but DON'T deny, It's going to have a very real "pucker-factor" until the Electrical System is proven-safe......Know what?.... I'd lay money on it NOT being with the present lash-up that safety and reliability are proven.

whatdoesthisbuttondo
 

"The fuel savings, engineering monitoring functions and passenger comfort make this an easy choice for them."

That's not how airlines choose planes. The things that count are cash going out and cash coming in.

Despite its unverified fuel savings the operating costs are much like any other plane.
It's expensive to buy and we'll see in 10 years what the maintenance costs are like.

Boeing undersized the -8 version so it will always have a challenge to generate enough cash to cover the costs.

This is not a dream, but reality.

The 787 Battery monitoring issue has been fixed with the replacement of the BMU. The rest of the fix with the casing etc is largely for public perception. In the future it will probably even be removed. That's what the (non boeing) engineers who have experience of it tell me. They said it's the kind of aircraft they have dreamt of. Not the kind of thing they say often. So, it's great to work with, great to fly, fuel efficient and passenger love it. The only people who appear against it are anonymous internet experts on here who have little or no experience of working on or operating this type.

Boeing isn't in tatters at all, the 787 is a fantastic aircraft. Anyone who has any real experience of operating it or working with it will tell you that. The fuel savings are real and quantifiable, they come from the operators not from Boeing. Airlines are ordering it because it is much more efficient than any comparable type due to the cruise flaps and reduction in bleed air systems.

The casing etc is largely for public perception. It will probably even be removed
 

This is becoming more and more like Boeing+FAA vs Public+NTSB.

With Boeing betting that the public don't care.

Oh at last. :D Having spent a few decades in aviation it has never ceased to amaze me that a large proportion of us look at the industry as 'something different'. Talk of sleek lines, bigger windows, 'a delight to fly' etc means next to nothing. If the aircraft is safe and costs less to run (or to be more precise, produces more profit per passenger) then it will be a winner.

The jury still appears to be deliberating about the safety issue. :hmm:

I'm sure I read somewhere, about 6 months ago, that the fuel savings experienced by ANA were actually slightly better than the Boeing claims.

In terms of maintenance, obviously time will tell a better story, but the scheduled maintenance involves a small fraction of the hanger-time of 'traditional' airliners. Very limited corrosion-checking, instrumented bolts and less than 30% of the wiring of a 767, mean a lot less labour.