Heathrow crash

Hi,

See the report into the Heathrow crash has concluded it was 'probably' fuel
line icing? Seems a bit vague to me, slightly worrying a definite cause
couldn't be found.

Interested in what the big iron drivers on here thought?

Cheers

Andy

Andy Hawkins wrote in
:

Hi,

See the report into the Heathrow crash has concluded it was 'probably'
fuel line icing? Seems a bit vague to me, slightly worrying a definite
cause couldn't be found.


Well, the evidence would have melted away.

Interested in what the big iron drivers on here thought?

I've heard a lot of talk about this accident. this isn't the only 777
that has had thrust issues on approach after a long flight, but it's the
only one who had both wind down at the same time.
I've heard today that the report came out but I can't find it on the
net. I'd be able to comment more fully if I had it to read.

It isn't exactly fuel icing, but what's called waxing. The fuel gets
very gooey near it's freezing point and doesn't flow so good when it
gets into this state. A typical freezing point for fuel is around -39C
and we have a temp gauge to tell us what the temp is in at least one of
the wing tanks.
Long flights in temps of as low as -70C can get the fuel that cold.
Actually, the total temp including skin friction would be about 25
degrees higher than that.
The main lines of defence, mechanically, at least, are that the
hydraulic system radiators are in the fuel tanks. This keeps the
hydraulics form cooking and also warms up the fuel a bit, and the engine
oil is cooled by fuel through a heat exchanger.
Older airplanes, like the older 737s and 727s, had fuel heat. This used
bleed air for short periods of time, usually 30 seconds, and heated up
the fuel in a big way. It had a failing in that if it got stuck on you
had to shut down the engine. That happened to me twice in 727s, but it's
no big deal and the shutdown is precautionary.
For some reason they don't install the bleed air fuel heat on modern
airplanes. I have no idea why, but it would definitely have saved that
BA airplane. I wouldn't be surprised to find they're considering putting
it back in.
The BA flight was polar and very long, so the temps would have been very
low. The crew would have certainly been monitoring the temps. they have
**** all else to do on a long flight like that anyway, and if the temps
were getting low, they would have probably requested a lower altitude,
and/or increased the cruise speed to increase the TAT (total air temp)




Bertie

"Bertie the Bunyip" wrote in message
...


Power snip-

You can almost say more and explain less than your brother Dudley.

But I'm sure you will keep trying.

"Lonnie" @_#~#@.^net wrote in :


"Bertie the Bunyip" wrote in message
...


Power snip-

You can almost say more and explain less than your brother Dudley.


Well, obviously al above your head, but then making a paper airplane also
falls into that category.

But I'm sure you will keep trying



Yep.


Forever and ever and ever and ever and ever and ever and ever and ever and
ever.


Bertie

Hi,

In article ,
Bertie the wrote:
Well, the evidence would have melted away.

Good point!

I've heard today that the report came out but I can't find it on the
net. I'd be able to comment more fully if I had it to read.

It's still just another interim report I understand.

http://www.aaib.dft.gov.uk/cms_resou...m%20Report.pdf

[snip interesting stuff]

Thanks for that, always interesting to read about possible causes of things
like this and whether any lessons can be learned. As you say, odd that
there's no way of 'warming' the fuel should it become necessary.

Cheers

Andy

Andy Hawkins wrote in
:

Hi,

In article ,
Bertie the wrote:
Well, the evidence would have melted away.

Good point!

I've heard today that the report came out but I can't find it on the
net. I'd be able to comment more fully if I had it to read.

It's still just another interim report I understand.

http://www.aaib.dft.gov.uk/cms_resou...m%20Report.pdf

[snip interesting stuff]

Thanks for that, always interesting to read about possible causes of
things like this and whether any lessons can be learned. As you say,
odd that there's no way of 'warming' the fuel should it become
necessary.


Yeah, I found mainstream news reports on it after I posted that. They
seem to be insisting it wasn't waxing, but actual ice in the fuel, which
would be a very rare event. i have had it happen to me using Avgas. When
100LL came out first it had a habit of keeping water in suspension. I
nearly came to grief, in fact, as did many others. that problem was
solved with 100LL AFAIK, though. When I heard about the accident first I
thought it might have been duff fuel they got in China, bu tI see no
finger pointing in that direction. in some parts of the world the fuel
is still pretty crude, being fairly wide cut. The engines sem to digest
it with no problem, but fire hazards while fueling are greatly increased
by them and I've often wondered if there are other risks. i have no idea
what they refueled with in China or how carefully the fuel's quality is
looked after.


Bertie

Hi,

In article ,
Bertie the wrote:
Yeah, I found mainstream news reports on it after I posted that. They
seem to be insisting it wasn't waxing, but actual ice in the fuel, which
would be a very rare event. i have had it happen to me using Avgas. When
100LL came out first it had a habit of keeping water in suspension. I
nearly came to grief, in fact, as did many others. that problem was
solved with 100LL AFAIK, though. When I heard about the accident first I
thought it might have been duff fuel they got in China, bu tI see no
finger pointing in that direction. in some parts of the world the fuel
is still pretty crude, being fairly wide cut. The engines sem to digest
it with no problem, but fire hazards while fueling are greatly increased
by them and I've often wondered if there are other risks. i have no idea
what they refueled with in China or how carefully the fuel's quality is
looked after.

As you say, sounds odd. Hopefully the final report will shed a bit more
light on things.

Thanks for the info.

Andy

Bertie the Bunyip schrieb:

....
I've heard today that the report came out but I can't find it on the
net. I'd be able to comment more fully if I had it to read.

It isn't exactly fuel icing, but what's called waxing. The fuel gets
....

Funny that you say that you haven't read the report (BTW intermediate,
not final), but this doesn't stop you to explain in detail what has
happened.

Even more funny that despite your attitude you're completely wrong. It
*was* icing. Read the report.

Bertie the Bunyip schrieb:

Yeah, I found mainstream news reports on it after I posted that. They
seem to be insisting it wasn't waxing, but actual ice in the fuel, which
would be a very rare event. i have had it happen to me using Avgas. When
100LL came out first it had a habit of keeping water in suspension. I
nearly came to grief, in fact, as did many others. that problem was
solved with 100LL AFAIK, though. When I heard about the accident first I
thought it might have been duff fuel they got in China, bu tI see no
finger pointing in that direction. in some parts of the world the fuel
is still pretty crude, being fairly wide cut. The engines sem to digest
it with no problem, but fire hazards while fueling are greatly increased
by them and I've often wondered if there are other risks. i have no idea
what they refueled with in China or how carefully the fuel's quality is
looked after.

Blah blah blah

Stefan wrote in news:6fade$48c11b12$54497efa
:

Bertie the Bunyip schrieb:

...
I've heard today that the report came out but I can't find it on the
net. I'd be able to comment more fully if I had it to read.

It isn't exactly fuel icing, but what's called waxing. The fuel gets
...

Funny that you say that you haven't read the report (BTW intermediate,
not final), but this doesn't stop you to explain in detail what has
happened.


I dodn't explain in detail what hapened, fjukkwit. I explained the
shortcomings of airliner fuel systems in general.

Even more funny that despite your attitude you're completely wrong. It
*was* icing. Read the report.


http://www.youtube.com/watch?v=mh6pZQX22CQ


Bertie