

The Jakarta Incident, or Rebooting 747 Engines In Flight - rubyrescue
http://en.wikipedia.org/wiki/British_Airways_Flight_9

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rubyrescue
Obviously a useful anecdote for anyone in the UK wondering why skies are clear
and planes are on the ground...

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neilk
I've heard of that anecdote but I still am not sure why it applies to the
whole of Europe, let alone England.

Is there even a standard for how much volcanic dust there can be before
airports are closed? How do they know we're currently over the limit? If they
answer is that they don't really know, how will they know when it's over?

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sampo
France, Belgium and Netherlands (at least) have been conducting test flights
during the weekend: <http://www.reuters.com/article/idUSTRE63G1U920100417>

Finnish Air Force had some fighter jets in air on Thursday 15th, when the ash
first hit Finland, and they've published some photos from inside the engines
after some contact with ash:

[http://www.flightglobal.com/articles/2010/04/16/340727/pictu...](http://www.flightglobal.com/articles/2010/04/16/340727/pictures-
finnish-f-18-engine-check-reveals-effects-of-volcanic.html)

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scorxn
Cool that they released the photos. Any insight into what we're seeing there,
and how it poses a risk?

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sampo
As far as I understand, the volcanic ash melts in the combustion chamber
(where temperature is like 1000 C), and then later can solidify on surfaces,
and may block cooling ducts and such.

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hugh3
Worth it just for this bit:

 _Despite the lack of time, Moody made an announcement to the passengers that
has been described as "a masterpiece of understatement":[3][4] “Ladies and
gentlemen, this is your captain speaking. We have a small problem. All four
engines have stopped. We are doing our damnedest to get them under control. I
trust you are not in too much distress._

I've always found the use of understatement to be an interesting difference
between British and American English.

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petewarden
My favo(u)?rite phrase from the article was "a bit like negotiating one's way
up a badger's arse". I'll be looking for an excuse to use that in my next
business meeting.

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amichail
In the Jakarta incident, the pilot descended 6000 feet because the copilot's
oxygen mask had a problem.

Was this a wise thing to do? What does the physics say?

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ars
Yes. The physics says there is more air lower down.

I don't really understand your question. Are you wondering if maybe staying
high is better because you can fly longer?

That's true, although I assume as they went down they gained in speed, which
also lets them fly longer.

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rubyrescue
all things being equal though if you have to descend faster than 'best glide
speed' the speed gain isn't worth the altitude loss. but not passing out due
to oxygen deprivation is...

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hugh3
What about for the purposes of restarting the engines?

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kjhgbnmm
Lower is better, max height for a restart depends on the engine but is
20,000-30,000 ft

