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photos of uncontained engine failure on Delta B744

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Photos have emerged of an uncontained engine failure suffered by a Delta Airlines Boeing 747-400 last week en-route from Detroit to Tokyo’s Narita airport in Japan. The engine failure, which occurred N661US on Oct 23, took place as the Pratt & Whitney PW4056-powered aircraft was climbing through 5,000 ft (aviationweek.com) 기타...

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Airway61
Hydraulic lines,normally have redundant"Back-up"systems.In case of engine damage,or shut-down.Even if one of the fuel-nozzles are faulty.Improper flow patterns can cause the internal fuel-nozzle to act as a cutting torch.Literally concentrating the flame tearing up The HPT T1-turbine blade(s)thrusting it through the whole Turbine"Hot'section.This aircraft was climbing.So the flow pattern on the nozzles were in primary.The intense heat from defective fuel nozzles.can destroy the turbine section quickly.Once a blade or shroud breaks free.Producing a cascading effect of damage to the Turbine Section.

Decimal
Looks like a bad maintenance for an old plane.
Decimal
Or it may be a simple bird strike.
indy2001
indy2001 0
Scanning through the lists at www.planesregister.com, it does appear that N661US was the first 747-400, flying from KMSP to KPHX on its maiden flight for NWA on Feb 9, 1989. Before being handed over to NWA, it was registered as N401PW, which would indicate it was a Pratt & Whitney engine test bed for a while. Ironic when you think about this incident. However, the airframe age wouldn't be a likely factor in an engine failure. In its 23.5 years of service, it's difficult to know how many dozens of engines have been used on that one single aircraft. Unlike airframes, I don't know of any tracking on the engines that's available to the general public.
WigzellRM
Well I'm glad they carried out their emergency procedures as per the book. They were at climb thrust which may partly explain why it was uncontained. It also brings to mind the uncontained failure on the A380, and how many systems that damaged.
preacher1
preacher1 0
Yeah it does Ralph. See my comment from above yesterday. It should be noted that there weren't any systems failures on this Boeing product.
aphil06
25,000...
num1tailhooker
Do not sit abeam the engine turbine.
chalet
chalet 0
Actually the "dangerous" rows are those ahead not abeam the turbines as the blade´s pitch will send them forward; would you and other bloggers agree?.
joehopwood
http://www.airport-data.com/aircraft/N661US.html
bishops90
Thanks Wayne. With the new layout here I missed the previous reference to the Kevlar protection that is already in place.
preacher1
preacher1 0
Yeah, I don't like the layout either. I complained to FA about it, but as far as I know, they didn't ask anybody before they changed it and I doubt they'll listen now. I think it stinks. You get a high comment article and have to pick all the way thru it to pick out a comment after getting an Email notify.
chalet
chalet 0
Wayne forgive my ignorance but does not Kevlar get destroyed when affected by high temperatures, or is it a good insulation material too capable to withstand the high temps associated with the outside of the casing around the hot section.
preacher1
preacher1 0
Man, I really don't know. Truthfully I didn't know it was in there until these posts came along. You'll have to ask somebody smarter than me, like an engineering type. I'm just a dumb old pilot.LOL
dbrooks84
N661US was delivered 08-12-1989 (leased from USB). MSN 23719
N662US was delivered 13-03-1989 (leased from FSBU). MSN 23720
N663US was delivered 26-01-1989 (leased from US Bank). MSN 23818
N664US was delivered 28-04-1989 (leased from US Bank). MSN 23819
N665US was delivered 01-09-1989 (leased from US Bank). MSN 23820
N666US was delivered 18-08-1989 (leased from GECAS). MSN 23821

These were the early ones.
Airway61
Major HPT Failure.T1 Blade shroud or both,Could have been ingested.Causing a cascading effect on the turbine section.With the high rpm and heat of the turbines.Producing FOD.The blades and hot sections became projectiles.Damaging the Turbine case.
preacher1
preacher1 0
Jose: you seem to have some mechanical background/expertise. Can you shed any light or offer any thoughts on Chalet's question to me up above?
bishops90
Or like Troy says below, sumpthin' blowed up!
tjoneillMO
Tim ONeill 0
You're not going to be able to contain fracture/failure of a rotating component like UA 232 (Sioux City) even with a Kevlar nacelle. This was the result of metallurgical defects in the fan disk, they blamed UA maintenance but the cause was the defect in the fan disk.
Turbine blade failures are by regulation required to be contained by engine design or shown to pose no threat to the A/C in flight. Fan blades are critical engine parts though.
BlutiG
Agreed, based on the first photo it looks like a failure on the high-spool. Either one of the latter stages of the high-pressure compressor or the first high-pressure turbine appears to have been damaged and ejected from the engine core. The scorching would lead me to believe it was the HPT. Temperatures in the combustion chamber & HPT average around 1000-2000 degrees C' when the engine has been running at take-off or climb power for a fair period. As far as why the core isn't shielded like the fan shroud, money/ROI/weight/reliability would be the best answers. The fan shroud is shielded because the blades are massive titanium/titanium edged monster chunks of metal and carry a ridiculous load; because they are the first point of contact for any FOD and therefor the most likely to be damaged. Armoring the core with titanium massively adds to the cost of the engine, and also can add 500-2000lbs to the overall weight of the engine. Finally the ROI on the idea, since uncontained core failures are extremely rare; most manufacturers boroscopically inspect and/or replace the core for overhaul every 1-2 shop visits depending on usage patterns and data from the ECUs. These overhauled engines undergo some extremely heavy maintenance and checks before being put back onto aircraft.
tjoneillMO
Tim ONeill 0
This looks like a late stage compressor blade failure. Uncontained blade release, no damage to A/C, engine shutdown and air return with safe landing. Crew had a few exciting moments but overall no big deal except the cost of repair. Old A/C does not equate to old engine--I think I saw this bird land in PHX in 1989, it was cool as you can get pretty close at Sky Harbor.

At the time of UA232 the thinking was that rotating parts were designed with a safe life and no inspection would be required. This has changed since to inspect at each opportunity.
Airway61
Wayne i replyed further down below
chusair
I am glad I do not fly Delta!!
preacher1
preacher1 0
This could and does, though not often, happen from time to time, with any airline. I applaud these pilots for a textbook recovery and safe landing. The only reason it is posted here is that it happened to make the media. Note that it happened a couple of weeks ago so it was not even an immediate thing. I'm glad they had a crew on there that knew how to FLY THE PLANE rather than panic and that is a testament to DAL for their training and quality of their flight crews.
chalet
chalet 0
Indeed Wayne, fly the plane and this is what the captain of the UAL 747 over the Pacific years ago towards Honolulu Int. when I believe it was eng. No. 3 that blew poking a huge hole to the fusalage killing some passangers/crew. His cool head and of course top notch training made him make the right dcisions.
Airway61
Engine failures.Will happen.On a positive note:The 747.Has the redundancy of three more engines.The unfortunate situation being.The aircraft has to dump fuel to land.The flight crew had the aplomb and control of the situation.To return safely.
sheka
mark tufts 0
i wonder the cost of damage to the engine
BlutiG
I'm no expert but it's probably a write-off. The engines they use for the blade-off test get written off; no parts are allowed to be salvaged. Once there has been a serious failure of the core its usually terminal. Better safe than sorry point of view; unforeseen stresses/collateral damage and all.
vfrflypacer
Im pretty sure N661US was the first 744 delivered to NWA... Is that correct?
vfrflypacer
Possibly even the first production 744? NWA was the launch customer too IIRC...
preacher1
preacher1 0
Are we trying to say it was old?LOL
chalet
chalet 0
Wayne I have to ask you a question that I have submitted to airline captains (777, 727 and 320), mechanical engineers, heavy duty jet turbines power plant engineers and others but nobody seems to be able to answer it for me: why is it that engine and airframe manufacturers and airlines for that matter too have not considered making the nacelles of light weight, high stress resistent titanium and make sure that an uncontained failure like this -or the terrible one on the United DC-10 over Siux City in the 1980s- be repeated. I am more than sure that somebody has to have thought about it but why it was not implemented.
preacher1
preacher1 0
I am going to have to join the rest of that crowd and for a certainty say I don't know. I haven't really thought much about it, but I have a feel that cost is at the root of it. In the event of a failure, you would still have an engine gone. The best you will do is to keep it from tearing up anything else. I don't know that you can protect against everything. In events like the Sioux City DC 10 there were some system changes to help prevent a recurrence of something that catstrophic but like I said, I don't think you can protect against everything. Even if they were to do as you suggest, given Murphy's Law, something else would happen. Based on what happened to the Qantas A380 awhile back, I think Airbus has some work to do besides any fix Rolls Royce makes, similar to changes made on the DC 10 after Sioux City, but again, you can't think of everything and in the end it will all come down to $ and ROI.
sbirch
sbirch 0
OK, I will chime in on the materials usage question. The incidents of turbine failure are low enough to where the use of the high-priced titanium outside the hot section was deemed unnecessary. While the United 83 DC-10 incident was a catastrophic failure of that turbine, it is critical to understand that it was a failure of the #3 engine attached directly to the fuselage that caused the severing of the hydraulics (an armchair design flaw). The inner linings of all turbine engine cowlings of this and subsequent eras are lined with kevlar to protect from high velocity ejection. As you noted here, blades spinning at 2000+RPM failed to cause damage to the fuselage, thus the design worked. Same with the Quantas that suffered no fuselage damage with a complete denigration of the powerplant. Hope that provides some insight.
a6n6d6y
andy talty 0
united 232 and number 2 engine
chalet
chalet 0
The price of titanium reached unprecedented levels some 10-15 years making it impossible to use, only the military were able to use it in their expensive weapons systems. However the price now is much much lower so this is not an issue. Indeed, Mr. Murphy has a tendency to show up at the most inappropriate moments but good engineering is capable to put him at bay, 99% of the times.
preacher1
preacher1 0
Yeah, but it's that 1% that will bite you in the butt. That is one reason I have always harped about the Airbus system possibly locking the pilot out of the loop if he tried to exceed the flight envelope. That little dab may be just what you need to pull your butt out of a crack and be the difference between recovering and crashing. IMHO
mdlacey
Matt Lacey 0
I thought it was that at least the planes of the fan blades and maybe of the compressor blades were armored within the engine, but that those of the turbine blades are not due to weight necessary to contain the higher energy blades. Unfortunately AE 521 was 13 years ago so the memory is a little fuzzy.
LenSmetona
Hi chalet,
There is consideration given to turbine failurs. The geometrical plane that turbine is in is not supposed to intersect with any critical part of the airplane, including the pressure vessel (cabin). If it does, there needs to be distance, or, a puncture proof material surrounding the turbine. Titanium is nice, but there are other materials today, like composites. Note that this covers the turbine, the hot part of the engine, the most highly stressed part, but not cover the other big spinning parts, like the compressor sections. If something lets go in the front of the engine, it will likely go through the engine causing much mayhem, and there will be flying parts all over. Len S
chalet
chalet 0
Hi Len, I believe that in the Qantas 380 uncontained failure the parts that flew off the engine did indeed intersect critical elements such as the wing's leading edge, certain hydraulic lines and the fuselaje itself however due to some extraordinarily superb airmanship -and lady luck helped by having a total of 5 top noth captains inside the cockpit- they were able to save numerous lives. While not an expert on metallurgical matters however I would think that titanium is by far more resistant than Kevlar for containing failurees like this, would you agree.
preacher1
preacher1 0
Well Chalet, like I said earlier about that 380; I think Airbus has some work to do in that area besides whatever Rolls Royce does on the engine as it is Airbus that designs the systems and where they are placed
mynewego
mynewego 0
It was actually, thats number one of 16 currently flying.
BoeingFan59
Hmm by the looks of the damage and by the looks of the punctures. Seems to appear something may have blown up inside it.
HIZZHONER
Ed Wagner 0
How many hours were on that engine?
skuttlerats
Is this the reason why they're using 777-200LR/F for the Minneapolis to Narita flights lately? I miss seeing the 747-400's rotate out of KMSP every afternoon.
cs767capt
I bet the reason they switch equipment is wind related.The high alt winds increases/decreases at each season change.Another factor it the load factor,ie empty seats.Just my guesses. cs
SkyDelay
That would have happened just about right over my house ;(
bishops90
NHRA Fuel class cars are required to have Kevlar safety blankets and restraint systems on their superchargers which are highly overdriven and could spew debris at high velocity for hundreds of feet. I think a similar blanket design COULD stop the debris from a hot section failure such as this, or at least slow it down enough to prevent the kind of airframe damage we saw on the A380 / RR failure.

As pressure ratios and inteternal temps get continually pushed higher in search of greater efficiency, these types of failures will become more common.
preacher1
preacher1 0
See SBirch's comment above from yesterday. According to him there is some Kevlar in there.
vfrflypacer
Not at all, I think this machine was a classic, just notable that this appears to be the first 744... Just kind of neat... My first plastic 744 model was of N661US in NWA bowling shoe colors...

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