China Eastern engine failure

a reply to: Zaphod58

Is there any other materials other than kevlar that could be used? Steel plate would be a major weight issue I'm guessing.

a reply to: Xarian6

This isn't cutting corners, this is engines outpacing materials. You're talking about unprecedented engine pressures and temperatures, which means that they're running much faster, and at much higher power settings than ever before. Which means you're going to see uncontained failures again, until they come up with a new material to stop them again.

As for this incident, one of the things that is required for a plane like the A330 to be able to fly the route it was on is that it has to meet ETOPS certification. That means that it can fly safely on one engine for a set amount of time. ETOPS is rated at 90, 120, 180, and beyond 180, meaning that they can safely fly 90 minutes, 120 minutes, 180 minutes, or beyond 180 minutes on one engine safely. The A330 was one of the first to be certified at beyond 180 minutes (I believe the A330 can fly 240 minutes on one engine). Even at takeoff weight, the aircraft can fly safely on one engine long enough to dump fuel, and get back on the ground safely.

a reply to: Woody510

Some kind of composite material is probably going to be the next thing they'll use.

a reply to: Zaphod58

The ETOPS certification. Initially I was thinking that flying on one engine is binary, either the plane can or it can't. What would allow them to fly for only 90 minutes? The remaining engine is strained and possibly fails after that time?

a reply to: Zaphod58

I was just wondering that or maybe some sort of hardened ceramic/carbon fibre weave?

a reply to: D8Tee

They have to be within 90 minutes of a landing site for an ETOPS 90 rating. When you fly on one engine, you have to fly at a higher power setting. That's putting a good bit of strain on the engine. Most engines now, can handle the strain better than they could when they first started ETOPS ratings, which is why so many twins are Beyond 180 now, and can go 240+ minutes.

a reply to: Woody510

Probably. There are a few materials out there now that are under development that will probably work fairly well. That's one of the things about aviation, is that some components tend to develop faster than others, and you end up in a situation like this.

originally posted by: Zaphod58
a reply to: Woody510

Engines are hitting power levels and RPMs that are far beyond engines even 25 or 30 years ago. There are engines out there that turn in 100,000 pounds of thrust or more. And they're looking for more out of newer engines. They're going to have to find something that prevents uncontained failures better than kevlar as engines go forward.

The 772B-60 runs at a 36:1 pressure ratio. The JT9D on the 767-300 runs at 23.4:1, the CF6 runs at about 27:1, while the RB211 and PW4052 are about the same pressure range.

That's a good point, you can see the force on the aircraft in this engine failure, *(possible bird strike) at Manchester on a Thomas Cook takeoff. (Come to think of it Manchester seems to have a birdie problem with the other incident of the Thompson flight on takeoff.)



* The video says fan failure, while the airport said at the time the engine remained intact, but did say bird strike, I don't know the final outcome.

originally posted by: Zaphod58
a reply to: Outlier13

Landing overweight could be more dangerous than flying with one engine shutdown. There is a very real danger of damage to the airframe of a landing gear collapse if they land too heavy.

Yeah I understand that. My point is sitting there looking at a partially blown apart engine for an hour circling would be a bit maddening.

a reply to: smurfy

That was a fracture failure of a high pressure turbine blade.

On Dec 12th 2013 the British AAIB reported in their bulletin that the takeoff was rejected at 105 KIAS after a flash and smoke from the right hand engine and associated loss of power. The investigation determined that the right hand engine failed because of the fracture of the a single high pressure turbine blade as result of high cycle fatigue crack propagation, causing an engine surge and damage further downstream into the intermediate and low pressure turbines and nozzles. Although the investigation report didn't name the videographer, it is obvious from the narration they used the Simon Lowe's video shown below as evidence into the investigation, too.

The AAIB reported that both IP (intermediate pressure) and LP (low pressure) spools of the engine became seized as result of debris jammed between turbine rotors and casings during run down of the engine.

avherald.com...

This is at least three times that this has happened that I've found so far. There's one that might be the same thing, as the damage to the cowling is in the same area, but it's a different damage pattern and it was reported as uncontained failure.

In 2006, an Emirates A330 was landing in Dubai, and had to perform a go around. After they throttled up to go around, the cowling came apart, in exactly the same way these two did.

Emirates A330.

In 2011, EASA warned of two operators, including the Emirates flight that found extensive damage caused by the sound damping panels around the interior of the cowling collapsing. They required inspections, but gave the airlines 24 months, 5,000 cycles, or 20,000 hours, whichever came first to complete the inspections.

Looking at the pics and the posts I'm wondering if it wasn't some kind of bearing failure up front. I've taken damage report photos on jet engines before with this type of damage and that was the cause. I'm glad it was contained to some extent because other posters are right. This kind of damage can bring a modern jet down in pieces with the loss of the aircraft and the passengers. Whatever the cause it needs to be found and fixed pronto. My best,

a reply to: airforce47

It appears to be the sound damping panels inside the ring cowl. They're collapsing and causing damage to the cowling. I've also seen speculation about an overpressure of the NAI system.

According to one of the ADs I've found on the engines:

Cracking has been found on the inner wall between intermediate dilution
chutes on a total of five front combustion liners of the standard corresponding
to Rolls-Royce SB RB.211-72-D133. The lives of two of these liners were
confirmed to be below the currently valid borescope inspection interval.
Ultimately, crack propagation could result in hot gas breakout with potential
of downstream component distress and multiple turbine blade release
beyond containment capabilities of the engine casings. Thus, cracking of this
nature constitutes a potentially unsafe condition.

ad.easa.europa.eu...

The engine looks real bad...its a miracle they fly for an hour and landed safely

a reply to: HannahForever

I'm still thinking it's a miracle none of the parts hit the fuselage or wing.

It appears to be the sound damping panels inside the ring cowl. They're collapsing and causing damage to the cowling. I've also seen speculation about an overpressure of the NAI system.

Water ingress and being in between checks..

In another story yesterday an Easyjet pilot held a vote with the passengers on whether they should attempt take off as he couldn't guarantee both engines would work. Easyjet link

Losing cowl doors is a thing, but that looks more nasty.

a reply to: Zaphod58
Once again Zaph your basic detective work is pretty close.

There is currently an AD as you have found that details a check of the acoustic liners on the inlet cowl of both CF-6 and Trent 700 powered A-330's. These acoustic panels are these days made from carbon fibre and have a surface that is etched with thousands of small slits 1-2mm wide and a few centimetres long, and based on the same principle you see used on the walls of sound recording studios or concert halls. They are looking for damage that has led to the ingress of water which of course freezes at altitude and leads to eventual disbonding from the cowl structure and failure. I personally dont see how this would necessarily lead to the entire structure failing as a result as the acoustic panels aren't really load bearing as such. Unlike in say a T/R (Thrust Reverser) where the cascade vanes are structural.

For those that dont know the inlet cowl on most large modern turbofans has a metal lip that is hollow and is heated with TAI (Thermal Anti Ice) also referred to by some manufacturers as mentioned by Zaphod as NAI (Nacelle Anti Ice) systems. These systems are heated air taken off compressor stages, it typically is around 40PSIG pressure wise. A failure in the titanium pipe that carriers this air into this hollow structure is the other theory kicking around and the one I personally first thought the likely culprit. It could be that either the line has broken through fatigue, a clamp between two sections has failed, somebody forgot to reinstall it properly after an inspection or inlet/engine change or a pressure regulating valve upstream has failed and allowed over pressurised air into the inlet structure. I dont recall on this aircraft but some have a blow out panel(s) to stop this becoming a major problem.

As for the queries regarding fuel dumping and circling Sydney. On A-330's some have fuel dumping and some do not. As a general rule 300 series do not have provision for dumping of fuel. This is because the 300 series does not have an activated centre wing tank and therefore its max weight does not exceed the design landing limit of the aircraft structure especially the centre box and its landing gear, even though it has a longer fuselage and can carry more passengers. There is a formula that is used during design and certification to calculate this which is based upon the percentage differences between zero weight, max takeoff etc. The 300 series was determined not to exceed this so is able to land safely with an almost full fuel load.

Now the aircraft in question was a 200 series A-330 and here it gets a little less straight forward. The 200 series can have a fuel dump system fitted but not all do. It comes down to customer choice and what kind of takeoff weight variant it is. Some operators require it and some dont, it frequently depends on whether they want to fly their aircraft near max range and whether they want to cough up the extra cost. I cant say for sure whether China Eastern does have it fitted.

The other problem here is that fuel dumping over Sydney and its surrounding areas is usually frowned upon unless a mayday has been declared. In fact airlines have been fined in the past for doing it. If its not an emergency you need to be a set distance from the Sydney basin and above a certain altitude in order to do it. I seem to remember years ago someone like United or Continental getting slapped for doing it where they shouldn't. Hence why this aircraft was circling for an hour to burn off fuel assuming it had a fuel dump sys fitted.

Apparently there is a bit of a funny story that the captain of this China Eastern 330 is alleged to have dropped the "F" bomb during his radio call. Something along the lines of "No:1 engine f**ked!", although some have speculated that he was trying to say "failed". I'm back on duty tomorrow morning and I'm betting that if not yet repaired it will be in one of our hangars. Obviously the ATSB, RR and Airbus will want to take a look. Repairs will probably be limited to a new inlet cowl, full inspection of the cold stream and T/R system for damage and any rectification of damaged fan blades. I will try and find out some more and if possible get some pics.

a reply to: thebozeian

The only thing that I can think of is that either the cracks are allowing corrosion in the outer skin of the cowling, or when the inner lining fails, it pulls on the cowling, and damages it until it fails, and starts a tearing of the cowling.