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United Flight from Denver to Hawaii blows engine on takeoff
9

United Flight from Denver to Hawaii blows engine on takeoff

RE: United Flight from Denver to Hawaii blows engine on takeoff

Giant 'ring toss'.

I think those 777 engines are the largest out there, at least diameter-wise.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff




Prat and Witney. Actually looks like it did its job pretty well no damage to the aircraft. and the casing intact.

I presume the flames are from burning carbon fibre and the engine oil.

RE: United Flight from Denver to Hawaii blows engine on takeoff

The burning areas are the carbon/epoxy cascades, part of the thrust reverser.

The inlet, fan cowls, most of the thrust reversers all departed. Not good. This is not supposed to happen in a fan blade out event. Though its not clear what part of the engine failed.

RE: United Flight from Denver to Hawaii blows engine on takeoff

I don't think it was a fan blade or compressor cutting loose . Technically all that stuff that's missing can depart and its still classed as a contained failure. But I agree not good.... But could have been much much worse.

They have a colossal bypass so the core is only about the size of that black dome on the front of the fan.

RE: United Flight from Denver to Hawaii blows engine on takeoff

just for interest i don't think its this engine

https://youtu.be/5-8_Gnbp2JA

They only do one test for certification if it passed.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Avherald article, for those like me who see the Daily Mail writing about aircraft failures as reason to doubt the existence of aircraft.

RE: United Flight from Denver to Hawaii blows engine on takeoff

RE: United Flight from Denver to Hawaii blows engine on takeoff

Is that a kevlar type of fabric on the outside of the turbine blades?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

This picture, from The Aviation Herald article that Eufalconimorph referenced, appears to show a missing blade from the primary fan wheel:



And here's a cutaway of the Pratt & Whitney PW4000 engine used on the B777-200:

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff

I once saw a video of the test of the titanium ring around the main fan simulating a fan blade failure. The ring visibly moved and hence although it has apparently done its job and contained the fan blade that event may have disturbed the cowling enough to allow air in and rip it off.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Your right John one is missing...

To be honest I would call that a failure but colossal success nothing hit the aircraft.

Although I bet the crew are happy it happened just after departure and not in the middle of a 180 mins ETOPS segment.

I love watching the engine tests. The icing tests are not as spectacular as the fan blade failures but the abuse they can put up with and still produce power is amazing.



RE: United Flight from Denver to Hawaii blows engine on takeoff

An engineering success, I think. Nothing is 100% reliable and this was one of the worst kind of failures for a jet engine and it ended without any injury.

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Not a success. By design and regulations the nacelle is not supposed to depart in a fan blade out event.

RE: United Flight from Denver to Hawaii blows engine on takeoff

They pretty much always do come off though. And if they didn't the shear bolts would go and the whole pod would come off due to vortex shedding vibration.

As long as a blade doesn't come out and bang through the hull pretty much every pilot would count it as a success.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Well there is that 'band' of Kevlar that they wrap the fuselage with, inline with the primary fan wheel of the engines. That's why there's always at least one missing window (I hate it when I get stuck in the 'windowless' seat).

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
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RE: United Flight from Denver to Hawaii blows engine on takeoff

They do that on turboprops and that's for ice coming off the blades. And its like a shotgun going off when it hits the plane.

And if the compressor disk goes it comes out supersonic and goes straight through the hull. Kevlar or not. I think you actually mean the compressor disk not the Fan.

There was a 737-800 that happened to in 2018 I think.

There is no requirement to contain disk failures.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Well that's what I was told by someone who used to work at Douglas Aircraft in Long Beach.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
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RE: United Flight from Denver to Hawaii blows engine on takeoff

Thanks John... didn't know, but thought it was.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

A bypass turbofan engine has several section.

If we look at the picture above the fan is the big bit on the front. with the orange next to it. Most of the air goes past the core and down the sides of the engine. There are vanes and stuff to keep its flow laminar.

The certification is if a fan blade comes off it stay's inside the engine body.

Behind that you can see a route that starts blue and then heads towards the back turning red. That's what we call the core there are usually 4-5 compressor "disks" and then it goes into the combustion area and then into the turbine at the back 5-6 of them rotational speeds go up to 13000 rpm. The disk just in front of the combustion chamber is the fastest spinning. And that's where you may have a blanked off window if the wing doesn't shield the cabin from that area.

People think its normal to do this, but actually its a fudge when they stretch an old model and re-engine it with larger bypass engines that won't fit under the wings. If you look at modern fresh sheet designs they all have the engines placed so the wing acts as a shield.

Put it this way the 737-100 doesn't have it and the MAX does :D

RE: United Flight from Denver to Hawaii blows engine on takeoff

This is a disk failure. I can only presume they were at a low power setting when it went and no where near max N1.



Like it or not that cutting loose at 13000 rpm is not going to get stopped by 8 layers of Kevlar weave mat. Or if it is then it will cave in all the structure around the mat and you would have less damage if you just let it puncture its way through.

And here is another disk failure where the whole of the fan came off. That's the A380 over Greenland.

RE: United Flight from Denver to Hawaii blows engine on takeoff

I suspect it may come down to corrosion issues after them not flying much. Although the freighter's should have been flying.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Sigh. There is no kevlar wrap on fuselages. There is a fan case around the low speed fan, which is the brown component in the pictures of the failed engine. Fan cases often contain kevlar fibers. Normally the fan cowl covers that area, but it came off, even though it is not supposed to.

RE: United Flight from Denver to Hawaii blows engine on takeoff

And the missing window area on fuselages is where the fuselage barrel sections are joined. Nothing to do with engine location. The exception is some turboprops that have a reinforced fuselage area in line with the propellers, since there is no fan case.

RE: United Flight from Denver to Hawaii blows engine on takeoff

News...
"The Federal Aviation Administration (FAA) has issued an emergency order calling for inspections of Boeing 777s fitted with Pratt and Whitney engines just 24 hours after a mid-flight incident in Denver. In a statement released Sunday evening, FAA Administrator Steve Dickson said: 'After consulting with my team of aviation safety experts about yesterday's engine failure aboard a Boeing 777 airplane in Denver, I have directed them to issue an Emergency Airworthiness Directive that would require immediate or stepped-up inspections of Boeing 777 airplanes equipped with certain Pratt & Whitney PW4000 engines. This will likely mean that some airplanes will be removed from service.' Meanwhile, Japan announced on Sunday that 32 passenger jets that use the same family of engine as the Boeing 777 that caught fire during the United Airlines flight from Denver to Honolulu on Saturday, have been grounded. The planes affected by the order from the Ministry of Land, Infrastructure, Transport and Tourism, are 13 aircraft operated by Japan Airlines. The other 19 planes are operated by All Nippon Airways. None of the planes are scheduled to fly on Monday. Both announcements occurred a day after the United Airlines plane suffered catastrophic engine failure shortly after take-off. The Boeing 777-200 aircraft, carrying 231 passengers and 10 crew on board, was heading to Honolulu on Saturday from Denver International Airport when debris struck the plane’s right engine, causing it to erupt into flames. The incident forced the pilot to make an emergency landing back in Denver just 20 minutes after take-off, at around 1.30pm local time. Remarkably, there were no injuries reported either on board the flight or on the ground. "

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

More news... "Based on the initial information, we concluded that the inspection interval should be stepped up for the hollow fan blades that are unique to this model of engine, used solely on Boeing 777 airplanes."

maybe some sort of fatigue failure?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Weight...

It's basically covered in this Wiki item:

https://en.wikipedia.org/wiki/Wide_chord

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff

Swcomposites I was pretty sure jets didn't have it and went looking at pictures.

A220 doesn't have it.

Although there is some newish rule about control run protection near the engine line.

The turbo props is for ice shedding not for in the event the prop blade come off. I have seen a lump of ice get through it as well to make a hole in the hull. So I suspect it wouldn't have a chance against bits of metal coming out the casing that recently were doing 13000 rpm.

Nice to see the FAA actually did something quickly though...

Those engines are now banned from Japanese airspace.

RE: United Flight from Denver to Hawaii blows engine on takeoff

On a historical note my Grandad at RR Barnsalwick worked on first acid etched turbine bladeds with cooling holes through the middle of them as a technician doing the grunt work. .

RE: United Flight from Denver to Hawaii blows engine on takeoff

This is the humour that's going round the spanner gods. That fix what I break.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Another use of duct tape... thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

and more news...
"The crack that led the fan blade to break on the United flight on Saturday was similar to one that occurred on a 2018 United flight, a person familiar with the preliminary investigation results who was not authorised to discuss them told the Bloomberg news agency.

In the latest failure, one fan blade cracked and broke off near where it attached to a rotating hub, according to the person. A second blade was also broken, apparently after it was struck by the first blade.

The fan blades on this specific type of PW4000 are hollow and made of titanium. The cracks appear to start from within the surface, making them impossible to detect on the surface. Airlines can use technologies such as ultrasound to find cracks beneath the surface.

Japan’s transport ministry ordered Japan Airlines Co Ltd (JAL) and ANA Holdings Inc to suspend the use of 777s with PW4000 engines while it considered whether to take additional measures."

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

That's not duct tape wash your mouth out. :D

Its called speed tape and is metal and costs about 50$ a roll. The technicians even have to go on special courses to be able to use it. It will stay stuck on even at 400 knts. They have a variety of tools to apply it.

There are even limits to the amount of it that can be used in certain areas. Some airlines survive on the stuff. Its one of the things I look for when I board a plane as a pax. The amount of it they have used and where it is. The more of it you see the more dodgy the maint level is. My current company the boss has banned it apart from get home outstation fixes.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Very interesting article on a previous blade failure and also how the inspections were a bit dubious

http://aerossurance.com/safety-management/ndi-fail...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: United Flight from Denver to Hawaii blows engine on takeoff

There has been reference to rpm in this thread, but a more relevant parameter with regard to kinetic energy is blade tip speed. Naturally, the larger the blade diameter, the heavier the blade (generally), hence the greater the kinetic energy on the loose if it happens to shed.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: United Flight from Denver to Hawaii blows engine on takeoff

Hence the need to have hollow blades.

I think they are fairly unique to that engine, or at least I hope so.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: United Flight from Denver to Hawaii blows engine on takeoff

2
There is probably nothing ever created by man (or woman) that is more intricately designed and engineered as jet turbine and fan blades. I found this neat article, which is more about material and forming process. https://www.americanscientist.org/article/each-bla...

It's still relevant to consider that this event could have been catastrophic but wasn't. Also, it's extremely rare for these parts to fail. I know there are reported incidents, but taken the number in service and the MTBF, the reliability rate is extremely high. Even considering that, it may still be excessive due to criticality and resultant nature of the events that could ensue.

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (That's not duct tape wash your mouth out. :D)


So that's what aeronautical guys call duct tape... someone on the ground, that had one of the large covers land in his yard... should have applied some duct tape and taken pictures... just for humour.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (Both inspectors stated that their training on the TAI was about 40 hours of on-the-job training. In comparison, the certification requirements for the commonly used eddy current and ultrasonic inspections are 40 hours of classroom training and 1,200 and 1,600 hours of practical experience, respectively.)


P&W cutting corners, too? There has to be a 'pile' of NDT methods that I haven't heard of...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (the greater the kinetic energy on the loose if it happens to shed.)


and part penetrated the fusilage just below the window line... could have penetrated someone sitting at the 'window' (I understand that some windows are missing, for this reason).

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Wow! Where can you get some of that speed tape? The grandkids figured how to get out of the regular duck tape some while ago.

RE: United Flight from Denver to Hawaii blows engine on takeoff

and more fuel...

"All Boeing 777s with the same engine as the passenger plane which caught fire after take-off scattering engine debris over a US city will be temporarily banned from entering UK airspace, it was revealed today.

Transport Secretary Grant Shapps has acted after Boeing recommended that airlines ground all 777s with the type of engine that blew apart after take-off from Denver International Airport on Saturday. "

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

I was on a flight once, where while we were waiting to finish loading I noticed out the window a guy using duct tape to secure something near the leading edge of the wing. Not sure what it was as it was on the underside, but it was only a small piece of tape, maybe six inches long. After he finished, he got another guy to look at it and they both seemed satisfied, so I never gave it a second thought.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff

Link

Excerpt from the webpage-- Since entering revenue service in 1987, Pratt & Whitney has delivered more than 2,500 PW4000-94'' engines that have collectively logged more than 120 million dependable flight hours on commercial aircraft around the world.

I guess I would consider that a pretty good testimony, but of course, I wasn't on one of those few planes that experienced a rare failure.

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Oops. I guess maybe it's this engine for the 777-200. No testimonial included on their webpage.
Link

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

And no one the ground in Broomfield Colorado was hurt.

My wife asked, so who would you turn your damages to, and I answered my insurance company, and let them sort it out. I would not want to waste my time trying to find out what airline, what engine manufacture, who maintained it, and so forth.

And amazing the plane can fly, and land without one engine.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (Hokie66)

Hollow fan blades? Is there a good reason for that?

Actually makes complete sense if primary load is radial tension from self weight, and moreso the hot side blades have passages for cooling air.

RE: United Flight from Denver to Hawaii blows engine on takeoff

cranky its what's called a pref A aircraft which all public transport aircraft are.

It means they have guaranteed performance after an engine failure. So they can climb and get back to a runway "one donk down" as we say in Scotland. in fact the 777 is whats called ETOPs certified which means it can go more than 60 mins away for a suitable runway on one engine. I think its 270 mins certified... In the trade ETOPS stands for Extended Twin OPerationS. But we say it stands for Engine Turning Or Passengers Swimming.

They can actually fail an engine before takeoff and still takeoff and land again. After a speed called V1 we are going like it or not.

When we talk about speeds the whole reason why jets work so well is that props have a limit due to the tips of the props going transonic and the resultant vibration. They put a cowl round them and they can run them faster and make the fans bigger.

Pretty much everything that comes out a turbine is super sonic in normal temperatures if it fails.

RE: United Flight from Denver to Hawaii blows engine on takeoff

The Avherald article got updated, including an image showing damage to the wing root. So it's an uncontained failure, with damage to the aircraft from flying shrapnel.

RE: United Flight from Denver to Hawaii blows engine on takeoff

A couple of pictures online today

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

interesting lenght at which the blade let go.

possible that would be a resonance nodal


while the news reports concerning the "fire", seeing that engine unblance shake was what would scare the hell out of me

RE: United Flight from Denver to Hawaii blows engine on takeoff

Look closely. One blade missing, the next one broke in the middle. Reportedly the blade fragments remained contained within the engine. The fairing damage may have been caused by some parts of the nacelle. Maybe not.

Brad Waybright

The more you know, the more you know you don't know.

RE: United Flight from Denver to Hawaii blows engine on takeoff

The only requirement is that the fan blades are retained. The rest of it is not protected. The hole in the side and the damage to the aircraft all come from other bits separating. That bit of the hull though is not pressurised.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Years ago flying JAL NRT to Singapore in a 747. On takeoff one of the engines 'flared', smoked and lost a few small bits out the back, and then you could see the white fire suppression system. They didn't change climb out angle or speed and off we went over the ocean for a few hours. I did like four engines.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: United Flight from Denver to Hawaii blows engine on takeoff

EdStainless's post reminded me of this that I came across a couple years ago. https://www.youtube.com/watch?v=EWAsQ3qldo8

BA 747 had a daily from Phoenix to London and this was it leaving one night. Lost an engine on takeoff and had dump some fuel & return.

RE: United Flight from Denver to Hawaii blows engine on takeoff

747 is rated to climb on 2 and cruse on 1, I guess that the Japanese aren't quite as up tight about it.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: United Flight from Denver to Hawaii blows engine on takeoff

All planes with more than one engine is supposed to be able to continue to fly with one of them not working. I know that should be obvious, but just in case...

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff

Could part of the problem be that aircraft have been mothballed for a long period of time... may have contributed?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

I didn't know what a ratchet mark was and found a source:

http://www.wanderlodgegurus.com/database/Theory/su...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

It's like learning a whole new language:

low cycle fatigue (LCF) fracture
time since new (TSN) 
cycles since new (CSN) 
Overhaul & Repair (O&R)
fluorescent penetrant inspection (FPI)
thermal acoustic imaging (TAI)
Principal Maintenance Inspector (PMI)
Fan Blade Off (FBO)
Maintenance Observation Program (MOP)
Flight Safety Foundation (FSF)
Maintenance Observation Program (MOP)

and, there's likely a couple that I missed...banghead

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (Thebard)

Since entering revenue service in 1987, Pratt & Whitney has delivered more than 2,500 PW4000-94'' engines that have collectively logged more than 120 million dependable flight hours on commercial aircraft around the world.

How many hours with these types of hollow titanium blades?

RE: United Flight from Denver to Hawaii blows engine on takeoff

The Boeing 777 does not use the PW4000-94". It uses the larger PW4000-112" engine (the one I showed on my 21 Feb 21 06:15 post). I may be wrong, but I think it's the larger engine that uses the hollow blades. The larger diameter main fan wheel increase the rotational forces on the blades, thus the need to lighten the rotating mass.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote (How many hours with these types of hollow titanium blades?)


A bunch... and when you think of a turbine at high RPMs, a bunch more...(This was the article I had to look up the abbreviations for)

According to United Airlines’ maintenance records, the No. 2 engine had accumulated 77,593 hours time since new (TSN) and 13,921 cycles since new (CSN) and 8,579 hours and 1,464 cycles since the last overhaul. The engine was installed on the airplane on October 18, 2015 [and] had operated 8,579 hours and 1,464 cycles since it had been installed. The entire fan blade set, including fan blade No. 11 had last been overhauled by P&W’s Overhaul & Repair (O&R) facility in July 2015. As part of the overhaul process, the blades underwent a fluorescent penetrant inspection (FPI) and a thermal acoustic imaging (TAI) inspection. P&W developed the TAI inspection process in about 2005 to be able to inspect the interior surfaces of the hollow core PW4000 fan blade. The records for the TAI inspection in July 2015 as well as an earlier TAI accomplished in March 2010 revealed a thermal indication in the same location as where the LCF crack occurred. The records for the fractured fan blade’s July 2015 TAI inspection was annotated ‘paint’ that, according to the inspector, was consistent with him accepting the indication because he thought it was an issue with the paint.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Do these things turn at 10,000 or 15,000 rpm or of that ilk?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Its normal with a 747 in some situations that they can continue.

In the US though there was up roar 10 years ago or so when BA had to shut one down after departure and continued across the Atlantic. it had to land in Manchester instead of Heathrow because of the increased fuel burn.

There was calls for the Pilot in command to be jailed.

The USA works with a dispatcher system where some licensed person on the ground can tell the crew what to do. In UK and Europe we have a flight dispatch system where they prepare all the paper work etc and then give it to the pilots and monitor things for any changes and try to keep things smooth. But all decisions are made by the pilots they just provide information. There was a bit of an issue with the US flight dispatcher telling them to land and it being ignored.

So the crew checked the manuals spoke to ops and continued.

It was just when the EU compensation had kicked in so continuing saved them quarter of a million.

Eventually after months they decided that they hadn't actually broken any rules. But afterwards the FAA changed the rules so in the USA airspace you have to land in the event of power loss. Before that as long as you didn't loose more than 50% performance you could continue. But then it screwed quite a few company's up and they wanted to change it back... But I don't know if they did or not. What they really wanted was one set of rules for N reg and one set for everyone else.

I believe you can't do it with a A340 or A380 because you loose to many system backups and once you run the checklists for those it tells you to land at nearest suitable airport.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Dik, it seems the fan spins around 2000 rpm and other sections in the engine approach 12k rpm. These numbers are from there triple redline test of the GE 90 series engine. I assume PW 4000 numbers are similar.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Sounds right to me.

I have 2500 rpm max for the fan and 13k rpm for the hp stage in my head for aircraft turbines but it will vary with engine type.

I also have 430 m/s fan tip speed going through my head...

The new geared PW1000G its 300 m/s and they are composite fan blades.





RE: United Flight from Denver to Hawaii blows engine on takeoff

Quote:

once you run the checklists for those it tells you to land at nearest suitable airport.

I dont think I would need a checklist, or a dispatcher. Da. Something's bigly wrong there.
When one engine blows, do you really believe that you still have theoretical reliability and confidence level in the other. I'd at least divide by 2, 'cause IMO you are more than half way towards seeing a black swan appear.

RE: United Flight from Denver to Hawaii blows engine on takeoff

quads are different to twins and its very dependant on the systems set up and what you have extra. The 747 also has 2 APU's. Have a google for ETOPS

Triple engine aircraft also have a different set of rules.


With twin engines you actually loose over 60 % of your performance when single engine.

Currently the 777 can be 330 minutes away from a suitable runway under ETOPS rules. The A350 is 370 mins.

Although I suspect the ETOPs approval will be reduced now for the PW engine aircraft back down to the standard 180 mins.

Single engine isn't that bad to be honest everything goes into back up mode. And everything stays working.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Don't need no rule book either. smile

RE: United Flight from Denver to Hawaii blows engine on takeoff

2
Put it this way if I had an engine shut down on me over Afghanistan or over some other choice countries in Africa and everything was working I wouldn't be landing at the nearest airport.

If I was just over the Alps heading north and everything was working and no structural damage after the engine was secure the conversation on the flight deck would quiet quickly move onto the pro and cons of currywurst over bratwurst in Munich Airport where we would be landing.

A mate of mine lost an engine over head Glasgow and landed in Birmingham. When asked by the AIBB why did you land there and fly past Liverpool and Manchester etc.

Answer

That's where my car was parked,

Nothing mentioned in the report on the subject.

RE: United Flight from Denver to Hawaii blows engine on takeoff

I don't know what a nominal tip speed is for a fan but Alistair's 430m/s sounds pretty reasonable. You can bet that all fans of similar technology run similar tip speeds at their design point. RPM follows from tip speed, QED.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: United Flight from Denver to Hawaii blows engine on takeoff

AP have the best security. Sleep there. Its the hotels, pipelines and pump stations that are dangerous.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Thanks, TB and AH...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

NTSB have declared it a contained engine failure.... Which might seem a bit of a meaningless statement but it makes a huge difference to the aircraft being returned to service which can now be just inspection and sign and flying again. If it was uncontained then there would have had to have been weeks of analysis and then a mod.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Thanks AH... didn't realise there was a distinction.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: United Flight from Denver to Hawaii blows engine on takeoff

Its a colossal distinction. The certification test for it involves killing an engine.

I posted this link previously https://youtu.be/5-8_Gnbp2JA

Here is some more for interest

https://youtu.be/wcALjMJbAvU

And the new GE engine doing icing tests. This one got killed later doing the fan blade failure. Its very rare they actually release the video of the fan blade tests. I am told that because its usually quiet explosive with cowls etc going everywhere and compressor/turbine disks banging out the side. But as long as the fan blade stays inside it passes.

https://youtu.be/YuW6hhKype4


This one on an A330 it also spat disks and did quiet a bit of damage to the wing. The runway at Manchester is long so they won't have been at max N1.

https://youtu.be/PS1YAX70edc

RE: United Flight from Denver to Hawaii blows engine on takeoff

Something was not contained based on the hole in the fuselage.
Link

RE: United Flight from Denver to Hawaii blows engine on takeoff

That's where the differences in opinion come from in this thread about what the certification requirements are.

I believe that its only the fan that needs to stay inside the carcass. And cowls and compressor disks it is normal that they exit as they so wish. And in my experience it is normal for damage to occur to the wing and hull near the engine. The control lines etc are meant to be split and routed so there isn't a single point of failure. To note this doesn't apply to the 737 series because of grandfather certification rules means its design to 1960 standards.

These rules came in after the Sioux City crash of United 232.

Here is the accident report from it.

http://i2.cdn.turner.com/cnn/2012/images/12/12/nts...

That accident features a lot in our training and also caused major changes in the certification standards.

That section is what's called aero fairing and isn't pressurised. Its likely to be cowling that's been blown off or the cowl icing system that came off with the big ring bit. If it had been a disk part from the compressor sections there would be a hole coming out the other side.

RE: United Flight from Denver to Hawaii blows engine on takeoff

Nope, nacelles are required to sustain predicted fan blade off loads.

And the damage to the underside of the aircraft was to the wing-to-body fairings, not to the fuselage pressure shell.

RE: United Flight from Denver to Hawaii blows engine on takeoff

That A330 video was very neat, Alistair. I showed my wife, she's not impressed. We're flying in a week.

RE: United Flight from Denver to Hawaii blows engine on takeoff

From what I could see it was a text book high speed abort. Nicely controlled. And Manchester air traffic and airport services at their normal high standards. To note that was a compressor blade going not a fan blade.

Safe flight and clear sky's for your trip

RE: United Flight from Denver to Hawaii blows engine on takeoff

Seems Boeing were in the process of redesigning the cowls etc starting in 2018. As there had been 7 incidents of debris falling off.

Japan has just banned PW4000-94 engine aircraft as well. Which for those of you that use air freight is going to cause you problems as they are used on 747's and MD11's I think.

I think that's linked to the 747 engine failure in the Netherlands.

https://www.msn.com/en-gb/lifestyle/travel/boeing-...


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