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scooterscot
14th March 2009, 11:39
I'm only flying Airbus from now on... As an engineer I'm astonished such safety measures are swept aside by Boeing (http://timesonline.co.uk/multimedia/archive/00502/cartoon__502983a.jpg).

centurian
14th March 2009, 16:35
I'm only flying Airbus from now on... As an engineer I'm astonished such safety measures are swept aside by Boeing (http://timesonline.co.uk/multimedia/archive/00502/cartoon__502983a.jpg).

Remember when Concorde had it's one and only accident.

The whole fleet was grounded, even though the accident was considered a freak event.

They had to re-enforce the fuel tanks and undercarriage - and because this meant more weight, they had to redesign a stack of other things to make them lighter (even down to redesigning the seats).

Only then were they allowed to fly again - over a year later.


At the time I was thinking "every time a Boeing falls out of the sky, they don't ground every 747/777/727 in the world"....

But I guess it will be cheaper to pay millions in compensation if people die, then to compensate airlines for billions for taking their planes out of commission for a year.

thelace
14th March 2009, 16:44
Eeek

It's not only flying to somewhere warm, you've got to get back to cold old blighty :mad

Yup, Airbus for me too

PM-Junkie
14th March 2009, 16:46
Are you trying to say that Americans are a bunch of money grabbing and corrupt idiots who would sell their own mother if they thought they could make a buck??? :eek

scooterscot
14th March 2009, 16:54
Are you trying to say that Americans are a bunch of money grabbing and corrupt idiots who would sell their own mother if they thought they could make a buck??? :eek

And their in-laws.

Made in America with pride.

AtW
14th March 2009, 17:09
The bad part that needs to be replaced was made by Rolls-Royce.

It's the UK aviation board that is trying to play it down - US report on the issue is far more open.

zara_backdog
14th March 2009, 17:11
Hate to upset you guys but the Engine Management Systems are designed by the same company. Also, depending on the type of craft they may even have the same Trent engin as in the 777 ( I think it is on one of the airbuses but maybe wrong here )

If it is going to crash it will crash !

Fred Bloggs
14th March 2009, 17:11
Actually, when I heard yesterday on Radio 4 "Rolls Royce should have a redesigned part available within 12 months" I sort of thought "SH*T!!!! don't go on a 777".

zara_backdog
14th March 2009, 17:23
Actually, when I heard yesterday on Radio 4 "Rolls Royce should have a redesigned part available within 12 months" I sort of thought "SH*T!!!! don't go on a 777".

Although redesigned Trent for the 777 will be reaady by 2010, boeing have stoped alot of orders for new developments and aircraft as they are on the S**t.

Versions of the Trent desinged by RR are in service on the Airbus A330, A340, A380 so do you wish to avoid those as well then!

centurian
14th March 2009, 17:39
Versions of the Trent desinged by RR are in service on the Airbus A330, A340, A380 so do you wish to avoid those as well then!

At least an Airbus can land on water when the engines conk out... :smokin

... although there isn't much water to be had on final, 300 metres short of 27L at Heathrow... :D



Also if Wiki can be believed, only the Trent 777 is affected

http://en.wikipedia.org/wiki/British_Airways_Flight_38#cite_note-2009-heat-exchanger-3

"Other aircraft, or Boeing 777 aircraft powered by GE or Pratt and Whitney engines, are not affected by the problem"

Fred Bloggs
14th March 2009, 18:06
Although redesigned Trent for the 777 will be reaady by 2010, boeing have stoped alot of orders for new developments and aircraft as they are on the S**t.

Versions of the Trent desinged by RR are in service on the Airbus A330, A340, A380 so do you wish to avoid those as well then!No, I understand it is a Trent + 777 = Problem thing, Airbus should be OK.

gingerjedi
14th March 2009, 23:38
"Boeing 777 - it's quite safe as long as you are flying to somewhere warm "

At 30,000 feet it's going to be -50c no mater where you are in the world, the problem came about when the plane descended and the ice thawed leaving small chunks floating about in the fuel lines, this could be just a freak accident but it could potentially happen anywhere.

In fact you could argue that it would be a bigger problem in a warmer area as the thaw could happen at a greater altitude.:eek

scooterscot
15th March 2009, 11:15
"Boeing 777 - it's quite safe as long as you are flying to somewhere warm "

At 30,000 feet it's going to be -50c no mater where you are in the world, the problem came about when the plane descended and the ice thawed leaving small chunks floating about in the fuel lines, this could be just a freak accident but it could potentially happen anywhere.

In fact you could argue that it would be a bigger problem in a warmer area as the thaw could happen at a greater altitude.:eek

The problem only occurs as the plane approached the runway not at altitude - why is that?

I would expect a blockage to be less of a problem in a warmer climate.

centurian
15th March 2009, 11:57
The problem only occurs as the plane approached the runway not at altitude - why is that?

I would expect a blockage to be less of a problem in a warmer climate.

It can happen at altitude as well. It's happened on at least two occasions. Once on final approach (Heathrow) and another at altitude over the US.

The main difference is that when it happens at altitude, the blockage can be cleared quickly by going to max throttle and melting the ice - flight BA38 stalled before the ice melted.

DaveB
15th March 2009, 12:39
The reason it was happening at all was because of the flight procedures being used. The engines were being run at flight minimum during decent - Idling to you and me. This is done to conserve fuel, and therefore money. With the engines at idle speeds there is not as much heat in the oil/fuel heat exchanger to keep the fuel above freezing point. This is the part that is being redesigned to make it more efficient at lower oil temperatures.

In the mean time flight procedures have bee changed to periodically run the engines at higher thrust to maintain the temperatures needed for the fuel to be kept warmer.

The are also introducing a new procedure to pump fuel between tanks when a temperature difference is indicated to mix the fuel and maintain a higher temperature.

centurian
15th March 2009, 12:50
The reason it was happening at all was because of the flight procedures being used. The engines were being run at flight minimum during decent - Idling to you and me.

777 is a plane where it is quite difficult to lose altitude quickly - a good thing as it gives it a huge range if both engines fail.

As you say, you need to throttle back to idle just to get from 36,000 ft down to 3,000 in a reasonable timeframe. Even just a bit of thrust will mean the bird will stubornly refuse to descend quickly enough.

But once flaps and landing gear are down on final approach - then you need some thrust to keep the plane in the air - just when all the ice has built up...

scooterscot
15th March 2009, 13:00
So what's needed is a heater for fuel prior to use to make sure optimum temperature is achieved. A small reservoir will also be required I guess for sudden fuel consumption, i.e. landing.

Hard to believe something like this does not already exist, FMEA would have shown this.

OwlHoot
15th March 2009, 13:06
Maybe what they need is to incorporate some kind of vibrating mechanism to keep shaking off the ice before it has a chance to build up. Either a lightweight ultrasonic gadget, or even a programmed adjustment to the air or fuel intake to run the engines a bit "juddery" for a few seconds if that makes sense and wouldn't strain anything too much (besides the ice).

Heck, I'm wasted in IT - I should be an aircraft designer :D

sasguru
15th March 2009, 13:18
Something's not quite right here. The US safety board used the words "high probability" for another event. Yet 777s with Trent engines have presumably been operating for years and there are several with airlines round the world. So is it reasonable to assume there have been thousands of flights by this aircraft with these engines? Say, being conservative, 1000 flights?
And yet there have been only 2 events (Delta and BA)? So there is 0.002 probability of an event in any particular journey.
I wouldn't worry about odds of that nature.


It's in the US interests to play it up - they want to boost their local (GE) engines and discredit the RR ones.


PS Recently came back from holiday long haul in a BA 777 - I think it had the RR logo on the engines.

scooterscot
15th March 2009, 13:46
being conservative, 1000 flights?
And yet there have been only 2 events (Delta and BA)? So there is 0.002 probability of an event in any particular journey.
I wouldn't worry about odds of that nature.

I'm glad these planes all have the same amount of flying hours on the clock.

scooterscot
15th March 2009, 13:48
Wonder where the affected aircraft got their fuel from.

Paddy
15th March 2009, 14:35
The old 747s used to pour condensation in the cockpit while landing. First officer would be using one hand with a chamois to wipe the bay windows with other on the throttle.

sasguru
16th March 2009, 09:37
I'm glad these planes all have the same amount of flying hours on the clock.

OK , OK 0.002 is an estimate. And why are the flying hours significant? It's not a metal fatigue problem, is it?
In any case I, for one, would not be worrying over much about flying in a 777-Trent plane.

Svalbaard
16th March 2009, 09:48
So when was the last time you went on a flight and had a choice of which plane you went on?

Granted, intercontinental you have a choice of many carriers but internal you'd be hard pushed to have the choice of planes.

DaveB
16th March 2009, 09:52
So what's needed is a heater for fuel prior to use to make sure optimum temperature is achieved. A small reservoir will also be required I guess for sudden fuel consumption, i.e. landing.

Hard to believe something like this does not already exist, FMEA would have shown this.

This is what the oil/fuel heat exchanger is meant to do. It uses heat from the engine oil to warm the fuel before it it pumped into the engine. Since the engines were being run at idle for prolonged periods the oil wasnt hot enough to warm the fuel properly so residual ice crystals in the fuel made it into the injection system and blocked it.

Menelaus
16th March 2009, 09:58
Surely though Airbus have the system that someone who I worked with years ago referred to as "Fly By Wire, Die By Fire"?