General Electric Gen EX engines suffering Icing Problems
General Electric Gen EX engines suffering Icing Problems
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Perik Omo

Original Poster:

2,326 posts

177 months

Saturday 23rd November 2013
quotequote all
I heard this morning that these engines fitted to Boeing 747-8 aircraft have been told to stay away from storm conditions and high altitudes as they are suffering from problems with icing, there have apparently been six incidents this year when they have suffered loss of power due to icing.

Mojocvh

16,837 posts

291 months

Saturday 23rd November 2013
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http://www.bbc.co.uk/news/business-25068222

Could be serious in flight. I'm sure their are cures on the way...with their associated performance deficits.

AnotherClarkey

3,698 posts

218 months

Saturday 23rd November 2013
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787 too. That 'plane can't catch a break (or doesn't deserve one?).

Chrisgr31

14,275 posts

284 months

Saturday 23rd November 2013
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Would have thought that after the BA 777 incident at Heathrow they would have paid particular attention to this during testing.

Z06George

2,519 posts

218 months

Saturday 23rd November 2013
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Chrisgr31 said:
Would have thought that after the BA 777 incident at Heathrow they would have paid particular attention to this during testing.
I thought BA used Rolls Royce engines in their Boeing aircraft rather than GE ones?

anonymous-user

83 months

Saturday 23rd November 2013
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I thought the 777 incident was due to fuel icing up. This sounds like engine icing. Surely separate issues.

Chrisgr31

14,275 posts

284 months

Sunday 24th November 2013
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Z06George said:
I thought BA used Rolls Royce engines in their Boeing aircraft rather than GE ones?
They did but you would still that engine manufacturers whether RR or GE would consider it. And regarding the other comment yes in the BA case it was the fuel icing but by redesigning the engine or part of it they fixed the problem. So not purely fuel.

motomk

2,186 posts

273 months

Sunday 24th November 2013
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Z06George said:
I thought BA used Rolls Royce engines in their Boeing aircraft rather than GE ones?
You can only get new Jumbos 747-8 with GE engines likewise the B777-300ER is only GE powered.
Not sure what they have on their 787, I would guess Rolls-Royces.








Z06George

2,519 posts

218 months

Sunday 24th November 2013
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That's interesting, I didn't know that.

Ayahuasca

27,580 posts

308 months

Sunday 24th November 2013
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Fitted to the ill-starred Dreamliner too iirc.

Ayahuasca

27,580 posts

308 months

Sunday 24th November 2013
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Fitted to the ill-starred Dreamliner too iirc.

Ginetta G15 Girl

3,220 posts

213 months

Sunday 24th November 2013
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Chrisgr31 said:
And regarding the other comment yes in the BA case it was the fuel icing but by redesigning the engine or part of it they fixed the problem. So not purely fuel.
There is a huge difference between Engine Icing and Fuel Icing!

In fact the only commonality is the word 'icing'.

Let me explain.

Aviation Kerosene tends to go 'waxy' at low temperature as ice crystals form in it. This is Fuel Icing. This means that it does not flow well nor ignite well - worst case scenario is an engine flame-out. In the Civilian world the basic fuel has no Icing Inhibitors added to it, airliners generally preferring to use fuel cooled oil-coolers to warm the fuel prior it reaching the burners. Another option being the manual addition of an anti freeze in flight (eg HS125 aircraft). Military a/c, on the other hand, generally use fuel to blended with an icing inhibitor (FSII).

Engine Icing, on the other hand, is where you are getting ice build-up in the engine intakes or inlet guide vanes (or, worse still, actually in the compressor(s) ) which results in the engine becoming 'choked' leading to a compressor surge or, worse still, a compressor stall. In the later case a locked-in surge may occur leading to extreme temperature damage to the compressor.



anonymous-user

83 months

Monday 25th November 2013
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Ginetta G15 Girl said:
Chrisgr31 said:
And regarding the other comment yes in the BA case it was the fuel icing but by redesigning the engine or part of it they fixed the problem. So not purely fuel.
There is a huge difference between Engine Icing and Fuel Icing!

In fact the only commonality is the word 'icing'.

Let me explain.

Aviation Kerosene tends to go 'waxy' at low temperature as ice crystals form in it. This is Fuel Icing. This means that it does not flow well nor ignite well - worst case scenario is an engine flame-out. In the Civilian world the basic fuel has no Icing Inhibitors added to it, airliners generally preferring to use fuel cooled oil-coolers to warm the fuel prior it reaching the burners. Another option being the manual addition of an anti freeze in flight (eg HS125 aircraft). Military a/c, on the other hand, generally use fuel to blended with an icing inhibitor (FSII).

Engine Icing, on the other hand, is where you are getting ice build-up in the engine intakes or inlet guide vanes (or, worse still, actually in the compressor(s) ) which results in the engine becoming 'choked' leading to a compressor surge or, worse still, a compressor stall. In the later case a locked-in surge may occur leading to extreme temperature damage to the compressor.
Exactly!

Kempus

168 posts

164 months

Monday 25th November 2013
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We have the ice crystal icing in our ECL. Is it also in the 74 and 78 ECL?

The 350 is a roller only ac at the moment and 380 will soon have the choice of alliance partners. Do you think it's down to fan blade diameter that it's now only coming to light or is it a GE thing?

Kempus

168 posts

164 months

Monday 25th November 2013
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We have the ice crystal icing in our ECL. Is it also in the 74 and 78 ECL?

The 350 is a roller only ac at the moment and 380 will soon have the choice of alliance partners. Do you think it's down to fan blade diameter that it's now only coming to light or is it a GE thing?

DudleySquires

870 posts

263 months

Monday 25th November 2013
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Ginetta G15 Girl said:
Chrisgr31 said:
And regarding the other comment yes in the BA case it was the fuel icing but by redesigning the engine or part of it they fixed the problem. So not purely fuel.
There is a huge difference between Engine Icing and Fuel Icing!

In fact the only commonality is the word 'icing'.

Let me explain.

Aviation Kerosene tends to go 'waxy' at low temperature as ice crystals form in it. This is Fuel Icing. This means that it does not flow well nor ignite well - worst case scenario is an engine flame-out. In the Civilian world the basic fuel has no Icing Inhibitors added to it, airliners generally preferring to use fuel cooled oil-coolers to warm the fuel prior it reaching the burners. Another option being the manual addition of an anti freeze in flight (eg HS125 aircraft). Military a/c, on the other hand, generally use fuel to blended with an icing inhibitor (FSII).

Engine Icing, on the other hand, is where you are getting ice build-up in the engine intakes or inlet guide vanes (or, worse still, actually in the compressor(s) ) which results in the engine becoming 'choked' leading to a compressor surge or, worse still, a compressor stall. In the later case a locked-in surge may occur leading to extreme temperature damage to the compressor.
I am nervous to question GGG, but since you mention waxing.. I'd go further and say that fuel waxing and fuel icing are two different phenomena. Fuel will begin to wax when its heaviest fractions begin to solidify at temps < -47degC. Water within the fuel will begin to freeze much sooner, although not necessarily at 0degC. Dissolved water can be super cooled and will only form crystals of ice upon contact with a surface - e.g. a fuel system pipe.

So in the specific case of G-YMMM, as the super-cooled-dissolved-water-laden fuel was drawn into fuel pipes during cruise and decent, slushy ice accreted on the surfaces but there was not sufficient flow to draw it further to the engines. However during final approach when more power was demanded, the flow rates increased and the ice did move to the engines: all at once! Blocking the FCOC and starving the engines.

FSII AIUI will not affect the fuel waxing point (called "freeze point" in the specs), but will lower the water icing point.

Ayahuasca

27,580 posts

308 months

Monday 25th November 2013
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DudleySquires said:
I am nervous to question GGG
You have balls. I would suggest a cricket box if you want to keep them.

S3_Graham

12,835 posts

228 months

Monday 25th November 2013
quotequote all
Ginetta G15 Girl said:
There is a huge difference between Engine Icing and Fuel Icing!

In fact the only commonality is the word 'icing'.

Let me explain.

Aviation Kerosene tends to go 'waxy' at low temperature as ice crystals form in it. This is Fuel Icing. This means that it does not flow well nor ignite well - worst case scenario is an engine flame-out. In the Civilian world the basic fuel has no Icing Inhibitors added to it, airliners generally preferring to use fuel cooled oil-coolers to warm the fuel prior it reaching the burners. Another option being the manual addition of an anti freeze in flight (eg HS125 aircraft). Military a/c, on the other hand, generally use fuel to blended with an icing inhibitor (FSII).

Engine Icing, on the other hand, is where you are getting ice build-up in the engine intakes or inlet guide vanes (or, worse still, actually in the compressor(s) ) which results in the engine becoming 'choked' leading to a compressor surge or, worse still, a compressor stall. In the later case a locked-in surge may occur leading to extreme temperature damage to the compressor.
I've only worked on the newer 125's (800b's/XP's and 1000's) but how do you mean manually adding fuel additive during flight? Like the TKS? Interesting stuff

anonymous-user

83 months

Monday 25th November 2013
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Didn't some hs125s use fluid release at the leading edges for airframe anti acing?

I didn't know they added a fuel additive in flight either.

S3_Graham

12,835 posts

228 months

Monday 25th November 2013
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Topbox said:
Didn't some hs125s use fluid release at the leading edges for airframe anti acing?

I didn't know they added a fuel additive in flight either.
All 125's have airframe de-icing on the wings and tail. Horrid stuff. Eats ally!