Boeing 787

[Clinton Huxley]

It's all academic to me...

You don't want to know about the problems they have with those ferries to Tasmania......

[JimC]

It's all academic to me...

You don't want to know about the problems they have with those ferries to Tasmania......

I have travelled on them several times, and loved every moment of it...

[Clinton Huxley]

It's all academic to me...

You don't want to know about the problems they have with those ferries to Tasmania......

I have travelled on them several times, and loved every moment of it...

And then, down in the engine room, something stirred.......

[JimC]

It's all academic to me...

You don't want to know about the problems they have with those ferries to Tasmania......

I have travelled on them several times, and loved every moment of it...

And then, down in the engine room, something stirred.......

It's been a while since something stirred in my engine room...

[cronus]

http://www.newscientist.com/article/mg2 ... wrong.html

Grounded: Where the Boeing Dreamliner went wrong

An advanced airliner brimming with untried technologies is on the tarmac until further notice. What did anyone expect, asks New Scientist's chief technology correspondent

CALL me a cynic if you will, but when I heard that Boeing's 787 Dreamliner had been grounded worldwide after a mere 15 months in service, my first thought was: "well, that happened sooner than I expected".

Having followed the plane's tortured development and path to airworthiness certification for New Scientist for more than a decade, it was clearly only a matter of time before something went wrong.

The reason is simple: the Dreamliner probably incorporates the broadest collection of untested aviation technologies since the Wright Flyer lifted off the beach at Kitty Hawk in 1903.

In the end it was the plane's advanced battery system that brought it down to Earth (though fortunately not with a bump; no one has been hurt) but it could have been any of a number of systems.

To recap what happened, on 7 January a fire broke out in one of the batteries in an empty Dreamliner at Boston's Logan airport. Shortly after that a battery in a second plane malfunctioned in flight, resulting in an emergency landing and evacuation at Takamatsu airport in Japan.

The US Federal Aviation Administration acted quickly, grounding the plane until the problem could be diagnosed and demonstrably fixed. Authorities worldwide followed suit. But the FAA also took another highly unusual, and perhaps illuminating, step: it decided to investigate its own certification process, asking in particular how it could have guaranteed as airworthy an aircraft whose electrical system has suffered a dangerous battery failure so soon, and which also has a history of electrical fires and circuitry failures, some even during the certification process itself.

Concerns over the Dreamliner kicked off over a decade ago when Boeing decided to create a civil airliner that would be both lighter than any of its previous jets and fly with leaner-burning engines to cut the plane's emissions of CO2 and nitrogen oxides. This would be delivered by two major technological step changes: a lightweight plastic fuselage and an all-electric, rather than hydraulic, control system. Both technologies have inherent risks that, even after certification tests, gave me cause for concern. In any case, emerging technologies rarely behave in their early years.

In the first step change, the fuselage was built from carbon-fibre-reinforced plastic (CFRP) rather than the tried-and-trusted aluminium alloy used ever since planes were first pressurised to fly above the weather in the 1950s. These composite materials - basically an epoxy resin shot through with tough carbon fibres - were already being incorporated into the fuselages of many aircraft. But the Dreamliner was the first to go all the way.

The trouble with CFRP is that under some conditions - the high g forces, for example, that can be experienced during severe turbulence - it can snap rather than give way gradually under stress like aluminium. And no one really knows how the material's properties change as it ages. Accelerated ageing tests involving cycles of heating and cooling are performed but may not truly represent real-world ageing.

(continued)

[JimC]

Remind me never to fly again...










Oh, hang on, I don't anyway!

[klr]

Meh. They haven't crashed and burned yet. Just burned. No-one's been killed. This isn't like the days of the de Havilland Comet. Or some of those Russian airlines ...

[cronus]

Meh. They haven't crashed and burned yet. Just burned. No-one's been killed. This isn't like the days of the de Havilland Comet. Or some of those Russian airlines ...

No chance of aluminium fatigue with a all plastic airplane.

[klr]

Meh. They haven't crashed and burned yet. Just burned. No-one's been killed. This isn't like the days of the de Havilland Comet. Or some of those Russian airlines ...

No chance of aluminium fatigue with a all plastic airplane.

That's one way of looking at it. Ever seen plastic break though?

[cronus]

Meh. They haven't crashed and burned yet. Just burned. No-one's been killed. This isn't like the days of the de Havilland Comet. Or some of those Russian airlines ...

No chance of aluminium fatigue with a all plastic airplane.

That's one way of looking at it. Ever seen plastic break though?

Every Dreamliner needs this in a repair kit.

[Jason]

Paging Coito.

[JimC]

Paging Coito.

What a way to interruptus a thread...

[Jason]

I believe he owns a lot of stock in Boeing.

[JimC]

Well, he puts a lot of stock in them, certainly...

Maybe he was born in Seattle, and it's hometown loyalty...

Certainly, I still believe that Geelong is the centre of the known universe...

[Jason]

Certainly, I still believe that Geelong is the centre of the known universe...

Well actually any point in the universe will appear to be the centre of the universe when measurements are taken from that point - from which we can hypothesize that the centre of the universe was at one time non-dimensional which makes life rather difficult for the professor at his chalkboard.