SWA1380 - diversion to KPHL after engine event

[pattern_is_full]

...front of nacelle 1 shredded/missing, not clear of cause (yet). Landed safe, no slides, evac via stairway.

http://6abc.com/live-southwest-plane-makes-emergency-landing-at-phl/3356147/

[Niner Lima Charlie]

Woman partially sucked out after engine parts break window.

https://www.nbcphiladelphia.com/news/local/Airplane-Makes-Emergency-Landing-at-Philadelphia-International-Airport-480008613.html

[Jet Jockey A4]

http://i17.photobucket.com/albums/b79/mlab601/29E2F79B-BB33-4FB4-A1E2-C24E699B98D8_zpswmufifqm.jpeg

The female passenger is in critical condition with head trauma because of flying debris from the engine.

[Yancey Slide]

https://www.cnn.com/us/live-news/southwest-flight-emergency/index.html

[WillFlyForCheese]

Pic of engine.

https://mobile.twitter.com/joeasaprap/status/986277894279311360/photo/1

[lomapaseo]

This will probably be raised as a serious accident and investigated by the NTSB.

This means details other than passenger comments will flow from the NTSB

[RAT 5]

No doubt there was considerable panic/discomfort in the cabin. Well done to all, including pax.

I was interested looking at the LED's on left side. They would be out of sight from LHS FD. Equally the engine nacelle was out of sight. Much would depend on CA <10,000, or perhaps a pilot did have a look. That would be interesting to know. The reason I'm curious is that there have been engine blow-ups that damaged LED's and caused an uncontrollable UAP/roll when deployed. I wonder if they conducted a flight control/flap test at 10,000'. This is such a rare event, and certainly not trained for, so anything the rest of us could learn is immensely valuable.

I appreciate most would want to be the ground PDQ, but much can depend on where you are, where your target is and what the state of pax & cabin is. I'm not suggesting something so simple.
The report, which would tell us, could take a long time, but the passing of knowledge might be more beneficial if quicker.

[ion_berkley]

Well despite the missing inlet it appears that the bulk of the fan is still there:
https://twitter.com/ABC/status/986274915400716288

[CityofFlight]

Question to the professionals here. One pax elsewhere in the aircraft, seemed to think they were already at 30,000'. Taking off from LGA and having just reached to SW part of NY, would they have been at this altitude that quickly? I question this because I think the situation with the pax next to the window might have been a lot worse at 30,000'. ??

Not minimizing the situation at all. Helluva an ordeal either way you look at it.

[Feathered]

City,

SWA1380 had filed for FL380, and was climbing through FL325 when the immediate descent began. At this point, the airplane was approaching the Susquehanna river in southern Pennsylvania. The closest suitable airport with airliner services and emergency services was MDT, but they needed a distance for the descent.

PHL was a good choice as they had to go that far anyway during the descent, and SWA has a large base at PHL. BWI would have been another option, slightly further away.

You can view the lateral flight track (https://flightaware.com/live/flight/SWA1380/history/20180417/1430Z/KLGA/KPHL) and the altitude track. (https://flightaware.com/live/flight/SWA1380/history/20180417/1430Z/KLGA/KPHL/tracklog)

[CityofFlight]

Thanks Feathered. The news is filtering more details and the woman involved was indeed seriously injured with a major head wound. That window breach, at that altitude...I can't imagine witnessing such a horrific event.

[India Four Two]

From the CNN link above:

CNN aviation analyst Peter Goelz said a type of engine that is usually "extraordinarily reliable" likely came apart on the Southwest flight, causing today's emergency landing.

"I have been on scene on these kinds of disasters — they're very rare, the turbofan engine is extraordinarily reliable," he said. "But in this case it looks like it came apart midair."

My bold. Is this the best CNN can do in terms of an “aviation analyst”? :ugh:

[VinRouge]

From the CNN link above:



My bold. Is this the best CNN can do in terms of an “aviation analyst”? :ugh:
Groundhog day...??

Uncontained CFM56-7 Failure: Southwest B737-700 27 August 2016 - Aerossurance (http://aerossurance.com/safety-management/uncontained-cfm56-failure-b737/)

Have to take a CFM LEAP of faith if flying on a -700....

[infrequentflyer789]

Well despite the missing inlet it appears that the bulk of the fan is still there:


It does, but we can't see all of it and there may be a blade gone in the area we can't see.

If there is a blade gone then this is looking awfully awfully similar to N766SW, same airline and type. That ought to sound alarm bells at NTSB.

Accident: Southwest B737 near Pensacola on Aug 27th 2016, uncontained engine failure (http://avherald.com/h?article=49d2d7e3)
https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_3472

Compare this pic (from N766SW) for instance:
http://avherald.com/img/southwest_b737_n766sw_pensacola_160827_3.jpg

Or look at this one and think impact point slightly up and right (in image coordinates):
http://avherald.com/img/southwest_b737_n766sw_pensacola_160827_2.jpg

Not sure which window went, but that would be my guess from the interior photo.

[andrasz]

Looking at the pic (https://www.pprune.org/rumours-news/607900-swa1380-diversion-kphl-after-engine-event.html#post10121557) of the window it appears that the piece of shrapnel did not penetrate the outer pane but came in at an angle, puncturing the skin adhacent to the window frame and then shattering the inner pane.


Edit: in light of later reports and photos this is clearly wrong, the outer pane is indeed missing (it appears to be intact due to the quality of the photo).

[Niner Lima Charlie]

Photos show the damaged window just aft of the wing. In the window photo above you can see the trailing edge and flaps.

[VinRouge]

Looking at the pic of the window it appears that the piece of shrapnel did not penetrate the outer pane but came in at an angle, puncturing the skin adhacent to the window frame and then shattering the inner pane.
Rough calcs I did at uni.. a single HP turbine blade has the same Kinetic energy as a 20mm round if it separates at the root. Takes a lot of containment to keep it all in, plus to keep a massively unbalanced core from shaking itself to bits, even if the FADEC catches it and commands an auto shutdown. Bit like a washing machine with a concrete block in it.

Could equally have been something heavy from the cowl, for example a big lump of bleed air valve for the engine ice kit, even if the blades had been contained.

[BrooksPA-28]

In the photo posted by Jet Jockey A4 the outer window shows no apparent damage. I know there is a hole in passenger windows to equalize pressure. Is it possible the window may have blown, not from "shrapnel" but as a result of the rapid decompression?

[brika]

Coincidence that it is Southwest again (August 2016)? How old is the aircraft? Maintenance issues?? Quality issues???

[VinRouge]

Coincidence that it is Southwest again (August 2016)? How old is the aircraft? Maintenance issues?? Quality issues???

FAA released a Service Bulletin for mandatory inspections. No suggestion of poor maintenance routine or procedures during the last event.



Preliminary investigation determined that the fracture in the blade initiated from the fan blade dovetail.

This condition, if not detected and corrected, could lead to fan blade failure, possibly resulting in uncontained forward release of debris, with consequent damage to the engine and the aeroplane.

To address this potential unsafe condition, CFM International issued CFM56-7B SB No. 72-1019, later revised, and CFM56-7B SB No. 72-1024, providing inspection instructions.



Looks to me the pax was sat aft of the fan. I very much doubt that an uncontained failure would make it back this far. Possibly debris from the cowl accelerated in the airflow hit the double glazing?

Looks like the port slat has taken a good old smashing along its length too. Fasteners open, but wouldnt be surprised if they have popped from the force of whatever happened.

[DaveReidUK]

Injured pax was reportedly seated in 14A which, as already noted, is just forward of the wing trailing edge.

That, and the indications that whatever penetrated the cabin was travelling at an angle and not tangentially, would suggest that it wasn't a liberated fan or turbine blade.

[CONSO]

Looking at the pic (https://www.pprune.org/rumours-news/607900-swa1380-diversion-kphl-after-engine-event.html#post10121557) of the window it appears that the piece of shrapnel did not penetrate the outer pane but came in at an angle, puncturing the skin adhacent to the window frame and then shattering the inner pane.


FWIW-despite the claim of passenger almost sucked out- the photo seems to show the outer pane mostly/all intact. And a close look at the bottom of what remains of the inner pane ( actually about 1/8 thick plastic seems to shows the typical center small dia hole (one of several) used to equallize the pressure slowly between the inner and out pane.

It therefore seems probable that the injury to the passenger MAY have been due to a plastic ' shard '. What seems puzzling is that would require an immediate high pressure between the inner and outer pane ??? or possibly the penetration of the fuselage by a part from the engine or related structure near the top of the window ( as stated above) . Will be interesting to see photos of the outside of the plane:confused:

In either case - the bit about being sucked out may NOT be supported- but a great figment of someones imagination which nowdays serves as news

[mkenig]

At about 5:00 minutes. NYCtr with 1380 until freq change. http://archive-server.liveatc.net/kmdt/KMDT1-ZNY10-Apr-17-2018-1500Z.mp3

Then KPHL twr about 18:30 in the mp3: http://archive-server.liveatc.net/kphl/PHL-Twr-Apr-17-2018-1500Z.mp3

Pilots sound understandably drained.

[underfire]

https://i.imgur.com/iPrdD9E.jpg

makes it look like entire window inner/outer are missing
"She wasn't like sucked out of the window or pulled out. But her like arms and her body were sucked, like sucked in that direction, from my vantage point. So you see people, from the back of the seat, holding onto her, you know, trying to keep her contained," Martinez told CNN.

Meanwhile, other passengers were trying to patch the hole in the plane.

"People in the other rows are — just trying to plug the hole, which sounds ridiculous, because you know people are using jackets and things, and it's just being sucked right out," she told CNN.

on a side note, did anyone notice that none of the pax were wearing the Ox mask correctly?

https://scontent-mia3-1.xx.fbcdn.net/v/t1.0-9/30704466_10211397649559167_1480270661933858816_n.jpg?_nc_cat =0&oh=b53d250fca81eb023998a9ae1e778f96&oe=5B68ED6E

[edmundronald]

Pix prove this is not SLF's overworked imagination ...
If this occurs too frequently, sooner or later an engine will ingest some bits and pieces of cowling orthe fasteners and then it will be a case of uncontained engine failure.

https://edition.cnn.com/2018/04/17/us/philadelphia-southwest-flight-emergency-landing/index.html

Edmund

UPDATE: One fatality. Maybe this wasn't altogether a "minor" incident.
https://nypost.com/2018/04/17/southwest-passenger-dead-after-midair-engine-explosion/

[CONSO]

JUST IN- ONE PERSON DIED ...

news/cnn-national/live-ntsb-holds-press-conference-on-southwest-airlines-flight/730881781

https://www.cnn.com/us/live-news/southwest-flight-emergency/

[tdracer]

Coincidence that it is Southwest again (August 2016)? How old is the aircraft? Maintenance issues?? Quality issues???
The age of the aircraft is immaterial - what matters is the engine (which is unlikely to be the same one as delivered on the aircraft).
The previous (similar) Southwest Event was attributed to metal fatigue of the fan blade root. Supposedly they implemented new inspection requirements of the fan blades after that.
Assuming this is another fan blade release (and it rather looks like it), I'm sure the attention will be on the heritage of this fan blade - what commonality is there with the previous event blade (e.g. made at about the same time) and at how the fan blade inspections are being performed.

Oh, and before people get too overly excited about two similar events - while it is certainly worrisome that both events occurred to the same operator, the CFM56-7 has accumulated roughly 50 million flight hours since the August 2016 event. One fan blade failure every 50 million hours isn't good, but it's not horrible either...

[Feathered]

From the CNN link above:



My bold. Is this the best CNN can do in terms of an “aviation analyst”? :ugh:

You must be new to CNN. ;) Sadly, whenever there is an aviation topic that we know something about, the amount of B.S. reporting is quite high. Soon we will hear from all sorts of "experts" that speculate about what they don't know about. Actually, substitute aviation topic for any topic, and it is about the same. For all of the newsworthy events that we don't know anything about, we can only assume it is no more accurate.

On the other hand, I highly recommend reading (United Airlines) Flight 232: A Story of Disaster and Survival, by Laurence Gonzales et al for in-depth reporting on a fan blade failure, what caused the failure, why it was not predicted or detected in advance (the underlying fault had existed in that blade for almost 2 decades before the catastrophe), and the effects that it had on people. While many of us know the details of that DC-10 flight in 1989 over Iowa and its heroic crew, this newer book goes much deeper into how one piece of titanium alloy changed so much.

[caevans]

Gotta put the Facebooker who took a video of himself with the O2 mask over his mouth up for a Darwin Award! Nice job!

[t1grm]

What a scary incident but, tragic as one death is, this seems to impress on me the resilience of modern aircraft. Surely a similar failure in the 70's/80's would have bought the aircraft down?

[Turbine D]

VinRouge,
a single HP turbine blade has the same Kinetic energy as a 20mm round if it separates at the root. Takes a lot of containment to keep it all in, plus to keep a massively unbalanced core from shaking itself to bits, even if the FADEC catches it and commands an auto shutdown.
Did you mean fan blade? HP turbine blades are just ahead of the LP turbine near the rear of the engine which looks rather intact and generally don't move forward when they fail as they are ground up by the LPT...

[vapilot2004]

The damaged cowl suggests a blade out event, but we just don't know for sure.

Not so long ago considered a rare event, uncontained engine failures seem to be happening with more regularity. The technology is mature, so maintenance inspection procedures and manufacturing QC would appear to be the first places to start looking for problems.

[completely deck]

Gotta put the Facebooker who took a video of himself with the O2 mask over his mouth up for a Darwin Award! Nice job!

Nice job making fun of people going through an emergency from the comfort of your arm chair! It really helps in situations like this when people like you are hypercritical of normal people going through incidents.

[lomapaseo]

The FAA funded a study of actual in-service events in the 90's to statistically evaluate the forward and aft trajectories of uncontained rotor engine parts. The greatest spread was seen to be fan blade particles with the outer panels often going forward into the soft inlet cowling and the innermost panels of blades going aftward if they did manage to escape through the engine casing.

However, it's not clear at this time whether the reported aircraft damage was caused by engine blade particles or release of aircraft cowling particles.

In this latest incident the degree of visible damage to the engine core cowls seem to be much greater than the earlier event pictured earlier in this thread.

[garp]

Nice job making fun of people going through an emergency from the comfort of your arm chair! It really helps in situations like this when people like you are hypercritical of normal people going through incidents.
If he finds the time to film himself he should also be able to put the mask on correctly. The FA showed how to do it just a few minutes earlier.

[garp]

At about 5:00 minutes. NYCtr with 1380 until freq change. http://archive-server.liveatc.net/kmdt/KMDT1-ZNY10-Apr-17-2018-1500Z.mp3

Then KPHL twr about 18:30 in the mp3: http://archive-server.liveatc.net/kphl/PHL-Twr-Apr-17-2018-1500Z.mp3

Pilots sound understandably drained.
No mayday call or did I miss that?

[thcrozier]

Who is the engine manufacturer? GE?

[tdracer]

Not so long ago considered a rare event, uncontained engine failures seem to be happening with more regularity. The technology is mature, so maintenance inspection procedures and manufacturing QC would appear to be the first places to start looking for problems.

I'm not sure they are happening at a higher rate - there are other items in play. The number of aircraft and their utilization are both up dramatically over the last 10 years, and with the internet and 24 hour news cycle we hear about the incidents right away. For example, a relatively young Trent 800 on a 777 had a fan blade release back around year 2000 - did you know about it? I do but that's because I was working the 777 at the time...
What I am concerned about is the way the fan cowls are coming apart after a fan blade release - that's not supposed to happen (and is taken into account during the design process). That didn't used to happen, and I'm at a loss as to what may have changed.

[hoss183]

In the photo posted by Jet Jockey A4 the outer window shows no apparent damage. I know there is a hole in passenger windows to equalize pressure. Is it possible the window may have blown, not from "shrapnel" but as a result of the rapid decompression?

What are you smoking, the outer pane (and all inner) are totally gone.

[tdracer]

Who is the engine manufacturer? GE?

CFM is a joint venture between GE and Safran (used to be Snecma) (French).
IIRC, Safran is responsible for the fan on the CFM56-7.

[VinRouge]

VinRouge,

Did you mean fan blade? HP turbine blades are just ahead of the LP turbine near the rear of the engine which looks rather intact and generally don't move forward when they fail as they are ground up by the LPT...

Sorry, was providing generic information. More likely to be a cold section part from the pics, I was trying to be illustrative of.the energy involved when these things go Pete tong and bits exit tangentially.

[er340790]

Quote: 'What a scary incident but, tragic as one death is, this seems to impress on me the resilience of modern aircraft. Surely a similar failure in the 70's/80's would have bought the aircraft down?'

Why, exactly???

[Joe_K]

You must be new to CNN. ;) Sadly, whenever there is an aviation topic that we know something about, the amount of B.S. reporting is quite high.

The "expert" in question claims to have been managing director of the NTSB. See http://www.oneillandassoc.com/our-team/team-member.cfm?mid=32 So from the point of view of the poor CNN staffer who's been tasked to find an expert and get them on air within minutes he must seem like quite a catch. Especially since he's "a sought-after commentator on aviation issues appearing regularly on CNN, Fox, CBS, BBC, CCCTV, Al Jazeera and Al Hurra TV" according to his bio...

[vapilot2004]

I don't have the statistical data available to disagree, Tdracer. I also agree with you that engine cowls do seem to be going missing rather often - perhaps the material selection of modern engine cowls is part of that. Back in the early days of turbojets, we had hulking hunks of aluminum around them.

That is not to say a well designed inner ring of plastic is not what the doctor ordered regarding fan blade containment, but statistics seem to agree with your observation regarding the cowling itself.

Who is the engine manufacturer? GE?


The majority of the core is manufactured by the American GE, with the French company Safran (formerly SNECMA) manufacturing and designing the fan, some ancillary bits, the nacelle, and the LP turbine and compressor assemblies. It has been among the most reliable turbofans ever placed into commercial service.

[CityofFlight]

VAPilot... Is this the same engine that many carriers are putting in place of the RR, for the Dreamliner?

[PAXboy]

You'll all be delighted to know that the BBC report one pax:
Passenger Marty Martinez posted a brief Facebook live with the caption: "Something is wrong with our plane! It appears we are going down! Emergency landing!! Southwest flight from NYC to Dallas!!"
After landing, he told CBS News that it felt like the plane was "free-falling".At least the BBC had the decency to put "free falling" with inverted commas but did not explain that it might have felt like free falling but was a controlled emergency descent as per SOP for every commercial airline. They had the chance to educate (just a teeny bit) but, I'm guessing, the lack of proper staff on hand who have knowledge to be applied, could be a factor.

[Stumpy Grinder]

Very curious, fan looks intact (albeit from poor images) I'm sad to say that my first instinct is an explosion of some kind.

[oldchina]

CityofFlight:...
"Is this the same engine that many carriers are putting in place of the RR, for the Dreamliner?"

If you're really from Seattle you should know better than that.
This engine has been around since the 1970s. No good for the Binliner !

[vapilot2004]

VAPilot... Is this the same engine that many carriers are putting in place of the RR, for the Dreamliner?

I wouldn't think so City of Flight. I believe even the highest thrust rated CFM would be too low for that aircraft.

[Thruster763]

VAPilot... Is this the same engine that many carriers are putting in place of the RR, for the Dreamliner?

No, 787 engine is much larger. Trent 1000 or GEnx-1B

[VinRouge]

Very curious, fan looks intact (albeit from poor images) I'm sad to say that my first instinct is an explosion of some kind.

The last one to let go in 2016 only lost one fan blade and looked equally intact....

Where perchance may this "explosion" supposedly come from?

[Stumpy Grinder]

The broken window position seems odd, 4 rows behind the overwing emergency exit, adjacent to trailing edge????

[Stumpy Grinder]

The last one to let go in 2016 only lost one fan blade and looked equally intact....

Where perchance may this "explosion" supposedly come from?

If you mean the A380 incident then you're incorrect, the fan departed company from the hub in that instance.

[oilyturbineguy]

Gotta put the Facebooker who took a video of himself with the O2 mask over his mouth up for a Darwin Award! Nice job!
Yes, it could be that the standard drop masks are in fact flawed in design, the circular shape does not encourage the unlucky/lucky user to don it covering nose and mouth.

[VinRouge]

No I mean the same model CFM engine that let go on another southwestern flight and on appearance, in exactly the same way. Check page one of the thread.

[dc8l382]

Female passenger deceased.

[Stumpy Grinder]

No I mean the same model CFM engine that let go on another southwestern flight and on appearance, in exactly the same way. Check page one of the thread.

My apologies for the mis-understanding, I'll check it out and get back to you.

[CityofFlight]

Thanks VAPilot & Thruster... appreciate the feedback. Wasn't sure if GE had a larger version.
OldChina, just because I lived in Seattle didn't mean I worked for Boeing. A few airlines are replacing the RR engine on the 787. I'm just curious which engine is being used.

[Stumpy Grinder]

No I mean the same model CFM engine that let go on another southwestern flight and on appearance, in exactly the same way. Check page one of the thread.

I checked, I'm not convinced that it's the same failure. My rationale (and I accept it is early days and may change as the facts change) massive damage to the inlet forward of the fan (blades go slightly rearwards and out and are contained (FBO test) not forward) and the position of the broken window, well aft of the fan.

Explosion hypothesis, shredding of the cowl and what appears to be scorching, the source - I have no idea, there should never be an explosive atmosphere in that zone of the engine.

[Mr Optimistic]

From the BBC,

When flight attendants told passengers to brace for impact, Mr Bourman said he and his wife worried for the worst.

As you might, but for an engine failure?

[VinRouge]

I checked, I'm not convinced that it's the same failure. My rationale (and I accept it is early days and may change as the facts change) massive damage to the inlet forward of the fan (blades go slightly rearwards and out and are contained (FBO test) not forward) and the position of the broken window, well aft of the fan.

Explosion hypothesis, shredding of the cowl and what appears to be scorching, the source - I have no idea, there should never be an explosive atmosphere in that zone of the engine.
Reckon that some hefty lump of the ejected cowl, or anti/de ice bleed air components will have more a part to play than a blade.

[BluSdUp]

Sad loss of life!
But job well done for the SouthWest Crew.
It looks like the flaps and slats worked and that is a bonus in a single engine landing.

This is indeed a complex situation with a lot of pressure on the Flight Crew to get on the ground ASAP.

On the history of the engine: The worlds most sold turbo fan engine bare none.
10 000 737 sold likely 30 000 plus engines !

I love my CFM56-7, if it starts it runs! Always!
BUT!
Tdracer:
As you say those cowlings are supposed to contain any fan blade failure, that is the secondary job( aerodynamics being main purpose?) .
And any compressor or turbine blade SHALL be contained and or spit out rearwards to be certified! Am I right so fare?
The AF A380 the other day had a similar event.

Anyway, do we know of any other CFM 56 incidents say the last 30 years of cowl separation due to fan blade separation or the likes.

Looking forward to more info on this one.

[Stumpy Grinder]

Reckon that some hefty lump of the ejected cowl, or anti/de ice bleed air components will have more a part to play than a blade.

Want to correct what I said above, I was comparing the wrong pictures, the failure effect does indeed look similar.

Any idea what was concluded on the previous incident? How did CFM address the uncountained failure? FBO should always be contained, turbine blade is considered infinite energy and uncontainable, another matter all together.

[Stumpy Grinder]

And any compressor or turbine blade SHALL be contained and or spit out rearwards to be certified! Am I right so fare?


Incorrect, a turbine blade release is considered as having infinite energy and is not contained - see Qantas QF32 A380 as an example. For cert compliance you have to show that no catastrophic event can occur as a result of a turbine blade release. For instance, if an APU turbine blade releases then it has to be demonstrated that the trajectory of the release does not compromise primary structure or flight controls, ie the release is satisfactorily mitigated by design.

Also it's not the cowl that contains the fan blade in the event of a FBO, it is the engine case.

[DaveReidUK]

A few airlines are replacing the RR engine on the 787.

You might want to review your source(s).

Is this the same engine that many carriers are putting in place of the RR, for the Dreamliner?

If the 787 used the same engine as the 737, it would have four of them. :ugh:

[Stumpy Grinder]

You might want to review your source(s).



If the 787 used the same engine as the 737, it would have four of them. :ugh:

....and we'd call it an A340-200/300..........

[wiedehopf]

Incorrect, a turbine blade release is considered as having infinite energy and is not contained - see Qantas QF32 A380 as an example. For cert compliance you have to show that no catastrophic event can occur as a result of a turbine blade release. For instance, if an APU turbine blade releases then it has to be demonstrated that the trajectory of the release does not compromise primary structure or flight controls, ie the release is satisfactorily mitigated by design.

Also it's not the cowl that contains the fan blade in the event of a FBO, it is the engine case.

Blades are supposed to be contained.
See https://en.wikipedia.org/wiki/Blade_off_testing

You are talking about turbine discs and fan discs, the central parts of metal holding all the blades.
But I guess you know that as you refer to a turbine disc failure (QF32).

[enginesuck]

Its appears the unfortuate pax may have been wedged in / partially out of the window at some point.

Looks a mess aft of the window in question
https://t.co/B1dFLZlaEq

[Stumpy Grinder]

Blades are supposed to be contained.
See https://en.wikipedia.org/wiki/Blade_off_testing

You are talking about turbine discs and fan discs, the central parts of metal holding all the blades.
But I guess you know that as you refer to a turbine disc failure (QF32).

Yes, indeed.

[BluSdUp]

Quantas was not suppose to happen Stumpy, You know that!
DC10 in Iowa was also a reminder of things unlikely!!
Anyway you know perfectly well what i mean!

Infinite energy, and explosions? Now what is that all about!!!

[whiteb]

Quantas was not suppose to happen Stumpy, You know that!
DC10 in Iowa was also a reminder of things unlikely!!
Anyway you know perfectly well what i mean!

Infinite energy, and explosions? Now what is that all about!!!

...... Q A N T A S .............

[PAXboy]

From the BBC,

When flight attendants told passengers to brace for impact, Mr Bourman said he and his wife worried for the worst.

As you might, but for an engine failure?
Well, some pax have read too many tabloid papers and tabloid TV! I doubt there was time to explain that it was a bad failure and they were getting to a low altitude and would park up just as soon as possible.

When there is a helluva bang and the rubber jungle with emergency descent? Very few on board would be able to follow the sequence and feel comfortable. As we all know, flying is very safe. Whilst uncontained failures are rare, I think it's even more so to actually kill a pax with it.

If I had been onboard, I would have expected folks to be panicked and presuming they might die. I know that Ms PAXboy (not married!) would have been terrified and I would have had to do a lot of comforting during and after the fact. I think we need to be generous.

[Stumpy Grinder]

...... Q A N T A S .............

LOL

"considered to have" infinite energy and I retracted the explosion hypothesis, do keep up.

I apologise to BluSdUp if English is not your first language.

[infrequentflyer789]

Tdracer:
As you say those cowlings are supposed to contain any fan blade failure, that is the secondary job( aerodynamics being main purpose?) .
And any compressor or turbine blade SHALL be contained and or spit out rearwards to be certified! Am I right so fare?
The AF A380 the other day had a similar event.

Anyway, do we know of any other CFM 56 incidents say the last 30 years of cowl separation due to fan blade separation or the likes.


Southwest Airlines flight 3472, 2016. Same engine, same type, same airline, and very similar event (IF this one is a blade off) including fuselage damage and depressurisation (occurred around the same altitude as well).

As far as I can find there are no other similar CFM 56 incidents, but I haven't done a lot of research to be sure on that. However, if these are the only two then question is are Southwest really unlucky or doing something different. As you say, there are a lot of CFM 56s out there.

[CityofFlight]

Southwest Airlines flight 3472, 2016. Same engine, same type, same airline, and very similar event (IF this one is a blade off) including fuselage damage and depressurisation (occurred around the same altitude as well).

As far as I can find there are no other similar CFM 56 incidents, but I haven't done a lot of research to be sure on that. However, if these are the only two then question is are Southwest really unlucky or doing something different. As you say, there are a lot of CFM 56s out there.

Agree. And while aviation analysts rushed to provide answers for news media, one of the news outlets just posted images of the SWA 2016 engine along side a pic of today's event. Be damned if they don't look very similar.

[pattern_is_full]

Was the last US fatal uncontained engine failure DL1288 (Pensacola, 1996)? I don't recall any others recently.

[infrequentflyer789]

Want to correct what I said above, I was comparing the wrong pictures, the failure effect does indeed look similar.

Any idea what was concluded on the previous incident? How did CFM address the uncountained failure? FBO should always be contained, turbine blade is considered infinite energy and uncontainable, another matter all together.

Assuming we're all talking about the same previous incident (SWA 3472 / N766SW) the NTSB investigation page is here: https://www.ntsb.gov/investigations/Pages/2016-pascagoula-fl.aspx

- no final report yet (that I can see), only an interim update
- appears they may have stopped after deciding cause of fan blade failure (and remedy?)
- sounds like they believe blade exited backwards not tangential, and wasn't responsible for the fuselage damage (therefore arguably making it a contained failure)
- there is no mention in the interim update of any further work on investigating the cowling failure or what hit the fuselage, it doesn't sound like they were interested...

[thepotato232]

What a scary incident but, tragic as one death is, this seems to impress on me the resilience of modern aircraft. Surely a similar failure in the 70's/80's would have bought the aircraft down?

This comment was lost in the shuffle for a bit.
Actually, the fundamental fuselage structure of the 737 is largely unchanged from the airplane's original design - with the first flight of the prototype in April, 1967.

[freshgasflow]

Grateful if someone can clarify for me ( SLF) if engines are supposed to , or not supposed to, contain blade separation ? I always thought that engines had "kevlar" type of protection to contain blade separation and that was a certification requirement. But some posts here seem to suggest otherwise. Grateful for any clarification.

[Concours77]

I checked, I'm not convinced that it's the same failure. My rationale (and I accept it is early days and may change as the facts change) massive damage to the inlet forward of the fan (blades go slightly rearwards and out and are contained (FBO test) not forward) and the position of the broken window, well aft of the fan.

Explosion hypothesis, shredding of the cowl and what appears to be scorching, the source - I have no idea, there should never be an explosive atmosphere in that zone of the engine.

The 380 out of Singapore (Qantas) experienced a departed IPT. It was number two. And was an extremely serious event. No fatalities. RR Trent, supposedly there was an “oil fire”, in the stator cave which caused an over speed of the turbine, which turned its rotor into liquid metal bearing. It’s in here somewheres.

Partial sever of the forward wing spar, and uncontrolled throttle on number one, plus a serious fuel leak made the emergency landing quite an accomplishment.

That one? Certainly not a fan issue, a very high energy turbine.

[TURIN]

To achieve certification the engine must pass a 'blade off' test. The engine casing immediately surrounding the fan must be capable of containing the rogue blade. Kevlar is used on some. In the pictures above of this incident, the fan case is intact (or at least looks so). The fan inlet cowl however is severly damaged and largely missing. It is not designed to withstand a thrown fan blade.
You tube has a few videos of engine blade off tests. :ok:

[lomapaseo]

The engine must demonstrate that it can withstand the intentional loss of a single blade and its consequences (e.g multiple blades in a domino affect, imbalance and/or seizure forces and fire and explosions).

The engine is normally defined by its front and rear flanges and as-shipped accessories.

Under the oversight of, continued airworthiness, corrective action against a demonstrated threat to safety need be addressed (could be at the engine level or the aircraft level)

I have doubts that blade parts took out that window

At this point, I have not seen enough of what's going on at the bottom of the engine that might have affected the cowl latches.

[3RDi]

https://instagram.com/p/BhrlERyHup7/

[WillFlyForCheese]

Gotta put the Facebooker who took a video of himself with the O2 mask over his mouth up for a Darwin Award! Nice job!

You know - you really should lighten up - one passenger is dead and others were injured. Quite a few of those folks likely thought this was their last day. People do what you might consider "strange" things when faced with certain death . . . write notes, leave mementos, whatever.

For most of the passengers on that flight - there was an explosion outside - and it appears as though bits of the outside came inside - injuring several passengers. I'm sure there were some horrid sounds associated with the event, coupled with the masks dropping, the aircraft "dropping" and a passenger being sucked out of the plane (or whatever actually happened). It is the stuff of movies.

Certainly better of you to think you'd be a smooth operator in any given emergency - and not fumbling for a clean set of drawers.

There's really nothing funny about what happened - and, sorry, but I don't fault the passengers for putting that ridiculously-sized mask on incorrectly. Folks panicked . . . give them a bit of a break.

[Ranger One]

This is the best image I've found of the engine. I've given it some mild enhancement. The damage pattern is... interesting. The fan looks substantially intact, or at least not completely disrupted - but the engine forward of the fan looks completely munted. It looks almost as if (note, as if, not saying that actually happened!) it hit something fairly substantial, but didn't ingest it.

Any thoughts on what could cause that damage? The other thing it looks kinda like is the 'explosive' damage you might expect from something like a compressor surge on steroids - you know the really loud BANG type with flames out the front of the engine; like that but something worse.

Interestingly, Southwest 438 back in 2007 was determined to be "...due to the No. 2 engine experiencing a release of its fan spinner through the fan cowl as a result of an unidentified object striking the spinner, separating it from the fan disk and causing the spinner to be ingested into the fan blades."

Damage in that incident: severe to fan, much less to cowling:

http://avherald.com/img/southwest_733_dal_3_640.jpg

EDIT for clarification: above is engine from Southwest 438 in 2007; below is today's failure:

[Highway1]

Reckon that some hefty lump of the ejected cowl, or anti/de ice bleed air components will have more a part to play than a blade.


Looking at the available pictures I would agree. I would suggest it is more likely that the outboard fan cowl flipped up and exited over the top of the wing and caught the window at 15A on its way past. Not nice for the pax sitting in that seat judging by the amount of blood on the outside of the fuselage.

[tdracer]

LOL

"considered to have" infinite energy and I retracted the explosion hypothesis, do keep up.

I apologise to BluSdUp if English is not your first language.

Lots of miss-information on this thread, and Stumpy you're not helping. I also hate repeating myself, but here goes:
1) Released/broken blades are not considered 'infinite energy' - engines are certified to contain blade failures - fan blades by the fan case containment ring (used to always be steel - many newer engines use Kevlar). Compressor and turbine blades are contained by the engine case (nearly always steel). Fan blades can and do initially move forward when released - remember they are basically pulling the aircraft forward so there is a significant forward force vector on the blade. The fan case containment ring extends well ahead of the fan to account for that but it's certainly not uncommon for fan debris to damage the inlet forward of the fan case.
2) Burst engine discs are considered 'infinite energy' and are allowed to be uncontained since sufficient shielding would be impractical (they are also not supposed to ever happen). The Iowa City DC-10 was a burst fan disc, the Qantas A380 was a burst turbine disc.
This event does not appear to be a burst disc.
3)The fan inlet cowl is not intended to contain engine parts - the fan case does that. It's purpose is purely aerodynamic (to provide 'clean' airflow to the fan face and a smooth aerodynamic surface around the engine) along with acoustic treatment to suppress fan noise. However it's not supposed to fail due to the forces of a fan blade out - and they are designed to contend with the forces associated with a fan blade out event. I'm sure the NTSB, FAA, and Boeing are all concerned that there have been recent fan blade out events where the inlet departed the aircraft.
4) The preliminary report on the 2016 Southwest fan blade out event attributed the release to metal fatigue, and the fan blade inspection requirements were supposed to updated to address that failure.

[infrequentflyer789]

New images on twitter: https://twitter.com/NTSB_Newsroom

Looks awfully like a missing fan blade in the elbow/forearm area...

https://pbs.twimg.com/media/DbBjwpkWAAAGTux.jpg

[Matt48]

Injured pax was reportedly seated in 14A which, as already noted, is just forward of the wing trailing edge.

That, and the indications that whatever penetrated the cabin was travelling at an angle and not tangentially, would suggest that it wasn't a liberated fan or turbine blade.
I used to like being seated over the wing, seemed a quieter and safer spot, wondering about the pax sucked into the blown out window, did she have her seatbelt on, would a belt hold you from a similar fate.

[er340790]

Tragic though the loss of one passenger is (RIP), it does demonstrate just how spectacularly safe flying by jet transport (in the USA at least) has become.

Since 2009 you would be more likely to win the lottery twice than to perish in a jet transport incident.

Hold that thought.

[Photonic]

I used to like being seated over the wing, seemed a quieter and safer spot, wondering about the pax sucked into the blown out window, did she have her seatbelt on, would a belt hold you from a similar fate.

I always figured that sitting over the wing box structure was a good place for the more survivable crash scenarios. Nobody plans for a freak window removal, and this does seem like just very bad luck in where the debris hit.

Too early to tell if the blown window caused the major trauma or anything after that, so a seatbelt might not have made a difference. They'll be talking about this one for years.

[lomapaseo]

tdracer
it's not supposed to fail due to the forces of a fan blade out - and they are designed to contend with the forces associated with a fan blade out event. I'm sure the NTSB, FAA, and Boeing are all concerned that there have been recent fan blade out events where the inlet departed the aircraft.

There's nothing special about the behaviour of a CF56 fan blade, yet given that there is a fan blade release the B737 inlet cowls have more damage than most other cowls on Boeing aircraft.

It shouldn't be difficult to address

[tdracer]

Hopefully this isn't 'fake news' - story about the Southwest pilot during the event:

https://heavy.com/news/2018/04/tammie-jo-shults-pilot-southwest-flight-1380-engine-hero/

Not quite Sully territory, but a job well done none the less.

[Mk 1]

Anyone else find reports that the cabin staff were trying to plug the hole odd? There would be bugger all items in the cabin with anywhere near the structural strength to do that - and items being fed through the hole could have snagged.

That seems strange...

[McGinty]

In an interview on CBC Radio, the passenger Martinez said that the unfortunate lady in the seat next to the window did have her seatbelt on. He said that a male passenger forward of her seat came back and was the main individual engaged in restraining her from being sucked out.

[tdracer]

tdracer
There's nothing special about the behaviour of a CF56 fan blade, yet given that there is a fan blade release the B737 inlet cowls have more damage than most other cowls on Boeing aircraft.

It shouldn't be difficult to address
Not just the CFM56/737 - an event a couple months back on a PW4000 777.

https://www.pprune.org/rumours-news/605391-ua1175-emergency-landing-honolulu.html?highlight=PW4000

BTW that photo posted by infrequentflyer shows surprising little damage to the surrounding blades. Interesting...

[givemewings]

Anyone else find reports that the cabin staff were trying to plug the hole odd? There would be bugger all items in the cabin with anywhere near the structural strength to do that - and items being fed through the hole could have snagged.

That seems strange...

Not if it started out small. If it were an entry hole from a small fast object they may have tried to plug it to slow loss of cabin pressure (it is a thing for a slow deconpression) but may not have realised it's not going to do much with structural damage.

The procedure is usually used when you have a faulty door seal and getting noise from it not for plugging a hole. Confusion perhaps?

[McGinty]

The 7 minute CBC Radio interview with Marty Martinez can be heard via the following URL. 'This plane is going down': Passenger describes moments leading up to emergency landing | CBC Radio (http://www.cbc.ca/radio/asithappens/this-plane-is-going-down-passenger-describes-moments-leading-up-to-emergency-landing-1.4624088)

[Mk 1]

Hopefully this isn't 'fake news' - story about the Southwest pilot during the event:

https://heavy.com/news/2018/04/tammie-jo-shults-pilot-southwest-flight-1380-engine-hero/

Not quite Sully territory, but a job well done none the less.

Indeed great job from the cockpit both during and after the event.

However we are back to seeing the word 'hero' thrown about again. It was as much in Tammy's own interest as it was the rest of the passengers to get the airframe down in one piece. Heroism should be left to describe those who deliberately and selflessly risk their own lives to save the lives of others.

In this scenario, if the hole had been much larger and an entire seat with passenger was about to be sucked out, yet another passenger seated in a 'safe' part of the fuselage undid their seatbelt to hold the person from falling out - that would be heroic. They would be endangering their own life to save others.

Pedant mode off.

[Photonic]

Indeed great job from the cockpit both during and after the event.

Agreed!

However we are back to seeing the word 'hero' thrown about again. It was as much in Tammy's own interest as it was the rest of the passengers to get the airframe down in one piece. Heroism should be left to describe those who deliberately and selflessly risk their own lives to save the lives of others.

In this scenario, if the hole had been much larger and an entire seat with passenger was about to be sucked out, yet another passenger seated in a 'safe' part of the fuselage undid their seatbelt to hold the person from falling out - that would be heroic. They would be endangering their own life to save others.

Yet to be verified, but here's the report in NYT:
https://www.nytimes.com/2018/04/17/us/southwest-airlines-explosion.html?ribbon-ad-idx=4&src=trending&module=Ribbon&version=origin&region=Header&action=click&contentCollection=Trending&pgtype=article

“The top half of her torso was out the window,” he said. “There was a lot of blood because she was hit by some of the shrapnel coming off the engine after it exploded.”

Mr. Kraidelman said passengers and flight attendants struggled “to drag her back into the aircraft.” When they did, she was unconscious and seriously injured, and flight attendants and passengers tried to revive her. Upon seeing the scene, one flight attendant began to cry, Mr. Tranchin said.

“They were doing CPR on her and using the defibrillator while we were landing,” Mr. Kraidelman said. “They were working on her while everyone else had their oxygen mask on.”

Mr. Tranchin said that one of the passengers helping had at one point placed his lower back up against the opening in the plane, in an apparent effort to help with the compression. The man did this for the next 20 minutes, Mr. Tranchin said, adding that the man later told him that the pressure at his back had been extreme.'

Maybe all of that was unnecessary, but it sounds like not just flight crew but pax were trying to help out. If true, that deserves some credit.

[mrdeux]

Pictures on AVHerald appear to show damage on the leading edge, at a number of points outboard of the engine.

[jugofpropwash]

Once the engine failure is contained the only emergency is for the injured pax. Other than the dreaded single engine landing. "Brace for impact" would panic the passengers even more. I would imagine that the cabin crew would be still highly stressed.

Not so sure about that. Pilots have no way of knowing if flying debris has done other structural damage. Photos on another site show damage to the leading edge of the wing, and what appears to be at least one small hole besides the damage to the window. Maybe flaps or another control surface jams, maybe something that has been weakened comes loose. Not to mention that it sounds as if half the passengers were busy with their electronic devices taking video and sending messages to loved ones. If they didn't listen to the briefing about how to put their mask on, are they actually going to listen to anything short of "Brace for impact"?

Also - an wondering if the female passenger who was killed was actually hit by the debris that broke the window? Thinking it might be equally possible that her injuries were caused by being sucked out the hole and/or by any loose items in the cabin that were sucked out past her and might have hit her.

[crewmeal]

One good reason to keep your seatbelt fastened loosely during the flight.

[AmericanFlyer]

Here's a fresh picture of the engine:

http://a57.foxnews.com/images.foxnews.com/content/fox-news/us/2018/04/18/former-ace-navy-pilot-id-d-as-hero-who-landed-damaged-southwest-flight-report/_jcr_content/article-text/article-par-3/inline_spotlight_ima/image.img.jpg/612/344/1524028026188.jpg?ve=1&tl=1

http://a57.foxnews.com/images.foxnews.com/content/fox-news/us/2018/04/18/former-ace-navy-pilot-id-d-as-hero-who-landed-damaged-southwest-flight-report/_jcr_content/article-text/article-par-3/inline_spotlight_ima/image.img.jpg/612/344/1524028026188.jpg?ve=1&tl=1

[Heathrow Harry]

One good reason to keep your seatbelt fastened loosely during the flight.


reports are that the lady DID have her seat belt fastened -

This is a one in a zillion case but it sure as hell make an impression on the public...... just about everyone remembers what happened to Auric Goldfinger but this was real - not James Bond...... :sad::sad::sad:

[Super VC-10]

https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380

[PiggyBack]

Gotta put the Facebooker who took a video of himself with the O2 mask over his mouth up for a Darwin Award! Nice job!

In the photo I have seen there are three people wearing the mask and they are all wearing it wrongly. The right reaction to this is to ask why and what can be done to improve the situation. Is it the design of mask, the training/communication or something else? What is the typical response? What factors affect it? Ideally the shape would be such that to wear it correctly is natural and comfortable and incorrectly difficult and uncomfortable. Is that possible? Can their be picures or diagrams on the mask? Should the safety briefing be changed?

Calling for a Darwin award for someone in an unexpected situation not of their making who tries but fails to follow safety instructions is more than harsh.

[DaveReidUK]

NTSB walkround video:

IFzLkFZUUS0

[Gauges and Dials]

I don't think any simulator experience can prepare you for this. BANG! -- something is wrong. Really wrong. You have good instrumentation and automation, and you know what you're doing, but at the end of the day you're still a fallible human and your ship is wounded in ways neither you nor the automation fully know yet -- and won't fully know until you try to do something, like extend flaps or even move the yoke a bit -- and find out whether bent metal, binding bearings, or severed hydraulics will stop things from happening the way you hoped -- or whether or when additional parts of the airplane will decide to take early retirement. Respect for all involved.

[ytpete]

Eyewitnesses can be unreliable and all, but in the Marty Martinez interview recording on CNN he describes a sequence of three events separated by several seconds each: an initial explosion sound, then oxygen masks deploying, and then the window exploding -- which he witnessed fro just two rows away.

Not sure if that reveals anything meaningful -- engine/cowl pieces could have come loose on a delay due to the outside airflow, or the window could have still been struck immediately but taken a few seconds to fully fail -- but I hadn't seen that bit about the sequence mentioned here before.

Question: is it concerning that passengers / cabin crew repeatedly tried to plug the hole with various objects that kept getting sucked out the window? What are the odds those objects could widen the hole further, or strike control surfaces on the tail?

[A4]

Incorrect mask donning.........Perhaps it’s because in my experience as a very regular traveller that only about 10-20% of pax actually bother to watch the safety demo or read the emergency card.....too busy on various social media platforms, reading the paper, chatting, playing with their iPad/phone etc etc

It’s (lack of) personal responsibility - too many think it’ll never happen to me / doesn’t apply to me.......and who thinks taking a selfie or going on Facebook live (whatever that is) is that important under the circumstances? :ugh::ugh::ugh::hmm:

A4

[jolihokistix]

For measuring rough damage extent, looking at the side profile of the engine from the starboard side, "Southwest.com" has lost seven letters down to "....st.com"

[BRE]

Regarding the injury and death, the reports just don't add up.

- There was a lot of blood -- the window looks clean.
- There was a heart attack.
- The victim of the heart attack died.
- The passenger who got sucked out died of her injuries.
- It has also been proposed that the fuselage got pierced in a position different from the window, so the injury and blood would have been elsewhere.


All in all, this could be one person or three who had this happen to them.

[hexboy]

Design of oxygen mask - #108 If the mask were shaped to fit nose and mouth, similar to that used in hospital intensive care units, it would be much simpler to fit correctly in the panic mode when they drop in front of the pax.

[clareprop]

Incorrect mask donning.........Perhaps it’s because in my experience as a very regular traveller that only about 10-20% of pax actually bother to watch the safety demo or read the emergency card.....too busy on various social media platforms, reading the paper, chatting, playing with their iPad/phone etc etc

Are all the critics sure the a/c is still in the emergency descent? The videos I've seen of that initial stage show everyone with correctly fitting masks.

[mickjoebill]

Incorrect mask donning.....
There is no opportunity for passengers to practice donning face mask or life vest, so what should we expect?

Anyone care to write about the pressure/suction created by the venturi effect (or other effects) in this incident?

Is there any danger of passengers being “sucked” out once cabin pressure has equilized?

Mjb

[ddd]

Wells Fargo executive killed in Southwest Airlines flight explosion | Daily Mail Online (http://www.dailymail.co.uk/news/article-5626379/Southwest-Airlines-flight-makes-emergency-landing-Philadelphia-engine-blows-out.html)

[Car RAMROD]

Design of oxygen mask - #108 If the mask were shaped to fit nose and mouth, similar to that used in hospital intensive care units, it would be much simpler to fit correctly in the panic mode when they drop in front of the pax.


In theory yes but in practice, I would be pretty confident in saying that some people will still get it wrong.

Have a search for people wearing life jackets in the Hudson ditching. There's a bloke that is wearing one the wrong way (they are not front/back specific, but they can be top/bottom!)


P.S I think the bags on the mask typically also have the instructions/diagram on them.

[A4]

....yes, but during the demo and on the safety card it clearly states “place the mask over your nose and mouth and breath normally”.....but if you don’t watch/read it then you’re putting yourself at a disadvantage (potentially life threatening) before you’ve even left the ground.

If proof were required about lack of attention, how many evacs have we seen where pax pause to get their carry on bags? That’s puts others at risk. Again the “it doesn’t apply to me” attitude. There’s a lot of it about.

A4

[Jhieminga]

Anyone care to write about the pressure/suction created by the venturi effect (or other effects) in this incident?

Is there any danger of passengers being “sucked” out once cabin pressure has equilized?
Mythbusters did a pretty good episode about this several years ago. In short: no (in my view).

[ChicoG]

Flight 232: A Story of Disaster and Survival[/U], by Laurence Gonzales et al for in-depth reporting on a fan blade failure, what caused the failure, why it was not predicted or detected in advance (the underlying fault had existed in that blade for almost 2 decades before the catastrophe), and the effects that it had on people

Although in fairness:

The Board determined that the probable cause of this accident was the inadequate consideration given to human factors limitations in the inspection and quality control procedures used by United Airlines' engine overhaul facility. These resulted in the failure to detect a fatigue crack originating from a previously undetected metallurgical defect located in a critical area of the titanium-alloy stage 1 fan disk that was manufactured by General Electric Aircraft Engines.

[clareprop]

I doubt the shape of the mask really matters just as much as it doesn't matter if the mask is not completely over both the mouth and nose. It is not delivering air to breath like a scuba system, it's delivering supplemental oxygen because the atmosphere above 10,000ft ('ish) does not have enough. As long as some of the gas is getting through, you'll live until the aircraft descends to a safe height.

[IrishBoy2]

Getting pretty sick of the OTT comments about the oxygen masks. Even if it is not over your nose just you mouth and you breath through your mouth, you'll be fine.

Why do I get the feeling the hysterical focus on this is by non-pilots?

[silverstrata]

With the SW 3472 incident in 2016, plus the SW 438 incident in 2007, and now this, I think the focus of attention needs to be as much on the cowl as the blade. In two (perhaps all three) cases the root of an N1 fan-blade failed (due to fatigue on the 2016 incident) and the blade separated.

But in all three cases the blade appears to have missed the containment ring and struck the cowl instead, causing a complete failure of the cowl, and all the attendant risks with all that material flying off into the slipstream. If you look at the N1 containment ring on the recent incident, it appears to be untouched all the way around. But the cowl took the full force of the departing blade, and disintegrated.

The N1 blade is under considerable aerodynamic forward pressure in flight, and will naturally spring forwards when released. But in static testing for cerification the blade still seems to hit the containment ring. Yet here it appears that the blade moved forward enough to miss the containment ring, and strike the cowl. Perhaps an engineer on this board might suggest why that might be. Why would the forward speed of the aircraft have any effect on the trajectory of the departing blade?

ST

[enginesuck]

Regarding the injury and death, the reports just don't add up.

- There was a lot of blood -- the window looks clean.
- There was a heart attack.
- The victim of the heart attack died.
- The passenger who got sucked out died of her injuries.
- It has also been proposed that the fuselage got pierced in a position different from the window, so the injury and blood would have been elsewhere.


All in all, this could be one person or three who had this happen to them.

If you look at the footage aft of the damaged window on the exterior you see quite a lot if blood actually

[Less Hair]

Maybe the visual part of the mask donning demo should be changed?
FA's on a demo just put it close to their face but never show the mask sitting on the face like when actually using it. So people see and remember the distanced position and never realize they have to put it over nose and mouth as demanded in the vocal text.

[TURIN]

In the photo I have seen there are three people wearing the mask and they are all wearing it wrongly. The right reaction to this is to ask why and what can be done to improve the situation. Is it the design of mask, the training/communication or something else? What is the typical response? What factors affect it? Ideally the shape would be such that to wear it correctly is natural and comfortable and incorrectly difficult and uncomfortable. Is that possible? Can their be picures or diagrams on the mask? Should the safety briefing be changed?

I have often wondered why the pax masks are different to the ones attached to the crew portable O2 botttles.
I'm guessing its a combination of (as someone above has already said) the yellow mask is a one size fits all compromise and is quite flexible. This also allows it to fit in the combined space of the overhead PSU.

Re: Damaged window. A while back a BA 777 suffered a loss of the hydraulic ADP access panel in flight. The panel hit a couple of windows edge on, bits of the panel made it inside the cabin, presumably through the seal between window and frame. Unbelievable really but never underestimate the energy in a CRP or fibreglass panel at that sort of impact speed.

[infrequentflyer789]

Media briefing here: https://www.youtube.com/watch?v=JxNS8H63oAc

Loss of fan blade confirmed, broken "right at the hub" and evidence of fatigue cracking at failure point. Sounds more and more like a carbon copy of N766SW / WN-3472 in 2016.

[strake]

Maybe the visual part of the mask donning demo should be changed?

As has been correctly pointed out, you do not need to have the mask completely or tightly over both your mouth and nose. The mask is only producing oxygen to add to the ambient air the user is breathing in the cabin which is now at the same altitude as the aircraft. There are many pilots and passengers doing the same in high performance unpressurised singles and twins every day using nasal canulas - for a considerably longer duration than would be required in the emergency that occurred here.

[Rob Bamber]

Mythbusters did a pretty good episode about this several years ago. In short: no (in my view).I've just rewatched it (season 1, episode 10). In their tests they couldn't get a crash test dummy to be sucked out of the plane, in any scenario.

However, they did blow out the window in a manner very similar to this one, and in the footage you can see how traumatic it would be for the passenger sitting next to it. Sucked out: no chance.

[RAT 5]

Amazing. On a PILOT chat forum not one discussion about what the pilots did. It's more like an engineers and health & safety chat forum. From page 1.
Mrdeux: in post #101 hinted at possible problems from a pilot perspective.
No doubt there was considerable panic/discomfort in the cabin. Well done to all, including pax.

I was interested looking at the LED's on left side. They would be out of sight from LHS FD. Equally the engine nacelle was out of sight. Much would depend on CA <10,000, or perhaps a pilot did have a look. That would be interesting to know. The reason I'm curious is that there have been engine blow-ups that damaged LED's and caused an uncontrollable UAP/roll when deployed. I wonder if they conducted a flight control/flap test at 10,000'. This is such a rare event, and certainly not trained for, so anything the rest of us could learn is immensely valuable.

I appreciate most would want to be the ground PDQ, but much can depend on where you are, where your target is and what the state of pax & cabin is. I'm not suggesting something so simple.
The report, which would tell us, could take a long time, but the passing of knowledge might be more beneficial if quicker.

[stagger]

Regarding the injury and death, the reports just don't add up.

- There was a lot of blood -- the window looks clean.
- There was a heart attack.
- The victim of the heart attack died.
- The passenger who got sucked out died of her injuries.
- It has also been proposed that the fuselage got pierced in a position different from the window, so the injury and blood would have been elsewhere.


All in all, this could be one person or three who had this happen to them.

Someone who has lost blood due to traumatic injury may suffer a cardiac arrest - or enter a state called PEA (pulseless electrically activity).

In the absence of a pulse, trained first aiders would likely start CPR and, if available, attach an AED (automated external defibrillator). Depending on the nature of the arrest the AED will decide whether or not to administer a shock.

All this activity would lead many bystanders to describe what they are witnessing as a "heart attack".

[Ozgrade3]

Question from one of my senior students today.

During a rapid depressurisation (greater than 3 seconds) does the outflow valve move to full close, thereby increasing the total volume of air exiting the window hole?

Was it a rapid or an explosive decompression.

Once level at 10,000 are the a/c packs turned off on the operating engine(s) to minimise the airflow through the cabin and out the new hole.

Quite ironic as I covered this very subject in class 12 hrs before the accident.

[kwh]

I've just rewatched it (season 1, episode 10). In their tests they couldn't get a crash test dummy to be sucked out of the plane, in any scenario.

However, they did blow out the window in a manner very similar to this one, and in the footage you can see how traumatic it would be for the passenger sitting next to it. Sucked out: no chance.

The sense I got from the various reports is that whatever broke the window also hit & seriously injured the passenger, probably knocking her unconscious, and so her upper body ending up jammed in the window with her having been partially sucked out of it would fit with the reports...

[framer]

Amazing. On a PILOT chat forum not one discussion about what the pilots did. It's more like an engineers and health & safety chat forum
It’s not amazing when you consider that there are only eight of us pilots left on the forum :)
I’ve been considering the way I would prioritise my actions in this circumstance. There would be a lot to do with the depressurisation and engine fail/fire indications occurring simultaneously. The first 120 seconds would be very intense.

[BluSdUp]

I would imagine that after 10000 level off ,Memory items engine Severe damage complete, the next on the Cpt list is: Will those damaged Slats jam??
In the -800 I can see half the wing, and I suppose the shorter -700 she could see a bit more , including some damage. F5 with just extend was a excellent place to stop.
Flap/slat asymmetry CL is a long and windy process. For the superstitious: Blade 13 was the culprit!

[Car RAMROD]

Amazing. On a PILOT chat forum not one discussion about what the pilots did. It's more like an engineers and health & safety chat forum. From page 1.


No doubt there was considerable panic/discomfort in the cabin. Well done to all, including pax.

I was interested looking at the LED's on left side. They would be out of sight from LHS FD. Equally the engine nacelle was out of sight. Much would depend on CA <10,000, or perhaps a pilot did have a look. That would be interesting to know. The reason I'm curious is that there have been engine blow-ups that damaged LED's and caused an uncontrollable UAP/roll when deployed. I wonder if they conducted a flight control/flap test at 10,000'. This is such a rare event, and certainly not trained for, so anything the rest of us could learn is immensely valuable.

I appreciate most would want to be the ground PDQ, but much can depend on where you are, where your target is and what the state of pax & cabin is. I'm not suggesting something so simple.
The report, which would tell us, could take a long time, but the passing of knowledge might be more beneficial if quicker.

In one of the recordings I listened to I think I heard the pilots saying to the fire crew that they were putting the flaps down (my guess is in case a fire starts/evac). If they were lowered at this point, I'm wondering did they pull them up initially after landing, or land with zero or reduced flap, or land with a normal (but not full) flap setting then extend them fully?

[Rob Bamber]

The sense I got from the various reports is that whatever broke the window also hit & seriously injured the passenger,I've found the mythbusters on YouTube. The window test is at 3:00. Take a look and see if you think it's nessesary for debris to enter the cabin to cause serious injury.https://www.youtube.com/watch?v=Fi1_1l7M8FA

[givemewings]

I have often wondered why the pax masks are different to the ones attached to the crew portable O2 botttles.

Depends on the airline. One I worked for the crew had the medical style clear fitted masks. FD had full face mask. The other (very large B777/A380 operator) crew bottles had the same round yellow masks as pax O2.

Yes it stinks, chemical generator hence the descriptions of 'smelt like fire(burning)'

[A0283]

Some notes...

@RAT5 perhaps a pilot did have a look
BBC has what appears piece audio of the/a female pilot talking to ATC where she says someone "went out"... If the pilot had taken a look in the cabin at that time she would have known that the pax was held inside. She may have gone in later though.

About oxygen masks... Reports since the 1960s that the majority of pax dont read the safety cards. And in two well documented cases in each only 2 of 180 pax knew how to operate and put the mask on correctly. That is extremely serious. So hopefully the Darwin remarks wakens some people (dont get mad, please read the card). In documented cases, if they can get it working, people generally put the mask over their mouth only. Apart from pax negligence you have to wonder about the ergonomy of the design. Certainly something that experienced engineers should know about. So I am surprised that the design has not changed. Even a specific minor change could help.

Masks is not the only thing of course...same stories about taking carry on luggage, how to open doors, how to jump n slide, where are the lifevests and how do you put them on. One marine ferry case had multiple people putting on their vest the wrong way which caused the vests to put them head down, which drowned instead of saved a number of ferry passengers in a survivable situation.

NTSB said that part of the cowl was found 60-70 miles away. Wonder what the damage sequence will turn out to be. Fanblade, cowl, window.. Or cowl, fanblade, with window in parallel... The pax could have been hit by fragments or might have been injured by edges of the window construction. There is documentation of hits and fatal hits, but as far as i know not of such cuts/blunt.

On leading edge damage and risks... The Hawker HS door that struck and stuck to the horstab leading edge brought the plane down. During the investigations they found multiple cases where the door had opened, multiple cases in which the door was lost, but only that case led to an accident. I think it was a DC9 where maintenance forgot to refix the leading edge of the lefthand horstab. On the second flight after maintenance the plane lost the edge which caused LOC and crash. Both might be called freak accidents, but certainly inportant to obtain as much detailed data as possible. NTSB Docket system is the best, so we will get some information in the end.

[wrighar]

Fan blade 13 missing at hub with evidence of metal fatigue

msn.com/en-gb/video/news/evidence-of-metal-fatigue-in-deadly-plane-engine-explosion/vi-AAw0iVd?ocid

[DaveReidUK]

I was interested looking at the LED's on left side. They would be out of sight from LHS FD. Equally the engine nacelle was out of sight. Much would depend on CA <10,000, or perhaps a pilot did have a look. That would be interesting to know. The reason I'm curious is that there have been engine blow-ups that damaged LED's and caused an uncontrollable UAP/roll when deployed. I wonder if they conducted a flight control/flap test at 10,000'. This is such a rare event, and certainly not trained for, so anything the rest of us could learn is immensely valuable.

The NTSB briefing makes it clear that the decision to deploy only Flap 5 for the landing was due to consideration of potential controllability issues.

It may or may not be relevant that LEDs are only partially extended at that flap setting on the 737.

[UPP]

The "expert" in question claims to have been managing director of the NTSB.

He was indeed. But that's the top admin post. It's NOT a technical job. It's admin.

His background is PR and admin. He has no specific technical qualifications I know of.

So, he's no more an aviation expert than I am. At least I used to actually work on planes! :mad:

[Eclectic]

The pilot, Tammie Jo Shults, is an ex USN fast jet pilot. She flew F18s and left the Navy as a lieutenant commander.
.

[DaveReidUK]

Yes, his current job is administrative, but his brackground is not (at least not exclusively) "PR and admin", although that has been true for some previous chairmen.

He said in the media briefing that he flew Boeing 737 for 10 years, so I think that would qualify him as an aviation expert.

Wikipedia (https://en.wikipedia.org/wiki/Robert_L._Sumwalt_(U.S._government_official))confirms he has been an airline pilot for 24 years (pilot for 32 years).

EDIT: The NTSB is also a board, not a company, so it does not have a "managing director", but a chairman.

You are quoting Bob Sumwalt's CV (NTSB Chair). That's not who we're talking about here.

[bsieker]

The NTSB briefing makes it clear that the decision to deploy only Flap 5 for the landing was due to consideration of potential controllability issues.

It may or may not be relevant that LEDs are only partially extended at that flap setting on the 737.

The photos on Avherald (http://avherald.com/img/southwest_b737_n772sw_philadelphia_180417_3.jpg) certainly look like more than 5 degrees. Avherald also said egress was via stairs, so there does not seem to have been a reason to lower the flaps (which serve as emergency "slides" for the overwing exits on the 737). Or is it standard procedure to lower the flaps after an emergency landing in anticipation of an emergency evacuation even if flaps were only partially deployed during the landing?

Bernd

[bsieker]

You are quoting Bob Sumwalt's CV (NTSB Chair). That's not who we're talking about here.

Yes, I noticed my mistake and deleted my post. Sorry for the confusion.

[Sailvi767]

In one of the recordings I listened to I think I heard the pilots saying to the fire crew that they were putting the flaps down (my guess is in case a fire starts/evac). If they were lowered at this point, I'm wondering did they pull them up initially after landing, or land with zero or reduced flap, or land with a normal (but not full) flap setting then extend them fully?

In most transport category aircraft you land with reduced flap if single engine to preserve go around margins.

[hoss183]

The sense I got from the various reports is that whatever broke the window also hit & seriously injured the passenger, probably knocking her unconscious, and so her upper body ending up jammed in the window with her having been partially sucked out of it would fit with the reports...

I doubt it. If the pax was in line with the axis of the fan there would have been a high energy penetration. Being that the failed window was behind the wing, its likely that it was an unlucky strike of some debris falling rearwards.
The report is she was out of the window up to her waist, and the injury likely occurred flailing in the slipstream against the fuselage.

[joncw8]

Identical Southwest jet in another emergency this morning. Flight 577 taking off from Nashville for Phoenix had to turn back 20 minutes later after a bird strike. Plane landed safely.

[Jhieminga]

During a rapid depressurisation (greater than 3 seconds) does the outflow valve move to full close, thereby increasing the total volume of air exiting the window hole?
The outflow valve is controlled using pressure differential as the major input variable. If the cabin pressure drops, then the outflow valve will close. The volume of air through the window will not change a whole lot, this is limited by the size of the hole and the max speed it will accellerate to through this hole.
Was it a rapid or an explosive decompression.
That depends on the definitions for 'rapid' and 'explosive'. In my view, this was not an explosive decompression as there was no further structural damage as a result of the first breach of the fuselage. But that's just my definition.
Once level at 10,000 are the a/c packs turned off on the operating engine(s) to minimise the airflow through the cabin and out the new hole.
The checklist will most likely not suggest this. Also, common sense dictates that without full knowledge of what the problem is, the crew will leave everything 'as is' to avoid additional problems. Also, they'll be concentrating on getting the aircraft down to 10,000', sorting out the engine issue and getting back on the ground at the diversion airfield. Theoretically (only that!) you could influence the airflow through the hole by manually selecting the outflow valve to full open, but why fiddle with something when you don't know what other problems you might invite.

Personal views only...

[ManaAdaSystem]

Aside from the noise and vibrations, it is quite possible the other engine indications were pretty normal. I don’t see much damage to the engine itself, apart from the missing fan blade.
The evaquation checklist on the 737 calls for (time permitting) FL40.
You would be able to see some of the damage to the leading edge from the cockpit in a -700 model.

As for the pilots actions, the aircraft and passengers/crew are safely on the ground. Not much to debate.

Job very well done! :D

[J-Class]

A user on AVHerald posted a question which merits an answer from the pilots here:

Downstream consequence of derated takeoffs?
By Lee on Tuesday, Apr 17th 2018 21:32Z

Due to the way they operate, it seems the highest N1 fan speed will be encountered during climb at high altitude rather than during takeoff (since derated power takeoffs are the norm). This accident appeared to happen at almost the exact same altitude as the previous [SWA] incident (around FL300), which would be when N1 is approaching the maximum seen during the flight. Perhaps they should do a periodic max power takeoff or ground tests to 104% N1 to flush out any bad fan blades. In the past these types of failures would occur on takeoff, everything would be contained, and the cowl would stay on. Either Boeing needs to figure out how to keep the engine cowl intact if the fan throws a blade at altitude, or SW needs to do more rigorous blade inspections.

It must be true that if this accident had begun on the ground, there could not have been injuries from cabin decompression.

Is there any merit in the argument that stressing engines to the max on the ground from time to time would be a good idea?

[ManaAdaSystem]

N1 is highest during the final part of the climb, typically around 100%.

[NWA SLF]

EMT interviewed said it was apparent from looking at the patient's upper body what the end result would be but as per training, she + another EMT continued CPR until the passenger could be offloaded. One would conclude injuries were from upper body in slipstream with consequent injuries.

Report on AvHerald is flaps 5 used due to control ability concerns so higher than normal landing speed. Interesting to hear some passengers say rougher than normal landing while others say very smooth. All in one's perception. It was good to hear that many passengers had a frantic response while probably more experienced passengers kept telling them to calm down, we are going to get through this okay. Importance of experienced travelers assisting cabin crew (only 3 of them) to calm those having a panic attack.

[Good Business Sense]

It’s not amazing when you consider that there are only eight of us pilots left on the forum :)
I’ve been considering the way I would prioritise my actions in this circumstance. There would be a lot to do with the depressurisation and engine fail/fire indications occurring simultaneously. The first 120 seconds would be very intense.

Spot on Framer - very intense indeed - for my sins I got this T-shirt in a full A330 in 1996 - engine failure climbing through 37,000 immediately followed by a depress. Thankfully, the engine didn't destroy itself in the way this one did - it just stopped with a bang. The biggest bug bear is the noise of the multiple warnings and cautions - noise can really interfere with a clear thought process and I don't think this is considered enough in accident investigation.

I've got to say that having our Air Traffic brothers and sisters helping in situations like these is a great workload relief in terms of navigation, aircraft separation etc, unfortunately, my day was departing from a small far eastern airport where ATC doubled the workload with their comms and actions. The controllers on this one were just fantastic - hats off to them too.

Sounds as though the flight crew did a really great professional job.

Best

[sandos]

I've just rewatched it (season 1, episode 10). In their tests they couldn't get a crash test dummy to be sucked out of the plane, in any scenario.

However, they did blow out the window in a manner very similar to this one, and in the footage you can see how traumatic it would be for the passenger sitting next to it. Sucked out: no chance.

Crash test dummies are very stiff compared to humans, you can see the dummy keeping its body inside the plane using its HEAD only. Would you have the power in your neck muscles for that? I doubt it.

[aliwyatt]

It can be seen that a minor amendment to the certification requirement may relieve the interference of multiple aural alerts expressed by "Good Business Sense"


"b. Multiple Aural Alerts
(1) Aural alerts should be prioritised so that only one aural alert is presented at a time. If more than one
aural alert needs to be presented at a time, each alert must be clearly distinguishable and intelligible by the flight
crew (CS 25.1322(a)(2)).
(2) When aural alerts are provided, an active aural alert should finish before another aural alert begins.
However, active aural alerts must be interrupted by alerts from higher urgency levels if the delay to annunciate the
higher-priority alert impacts the timely response of the flight crew (CS 25.1301(a)). If the condition that triggered the
interrupted alert is still active, that alert may be repeated once the higher-urgency alert is completed. If more than
one aural alert requires immediate awareness and the interrupted alert(s) affects the safe operation of the
aeroplane, an effective alternative means of presenting the alert to the flight crew must be provided to meet the
requirements of CS 25.1322(a)(1) and (a)(2)."

[DaveReidUK]

A user on AVHerald posted a question which merits an answer from the pilots here

Leaving aside the oxymoron inherent in that statement, the suggestion that

Perhaps they should do a periodic max power takeoff or ground tests to 104% N1 to flush out any bad fan blades.is simplistic in the extreme, being based on the assumption that if a blade is going to let go it will do so the first time N1 reaches a certain value and not on some subsequent occasion.

It's particularly irrelevant in this case, given that the NTSB is already reporting indications of metal fatigue at the blade root.

[Procrastinus]

Really puts me off long over water flights in twin engined aircraft!

[Mk 1]

Maybe the visual part of the mask donning demo should be changed?
FA's on a demo just put it close to their face but never show the mask sitting on the face like when actually using it. So people see and remember the distanced position and never realize they have to put it over nose and mouth as demanded in the vocal text.

This ^. Don't know if its a fear of germs or that they don't want to ruin their makeup but they are never shown on the face. However, the safety card will show how to use it - more fool those who don't read it.

[hoss183]

As pointed out, the mask does not have to be fully over both nose and mouth. Systems for providing oxygen to high alt flights in unpressurised a/c do include just nose clip tubes.
Any by the way just to be pedantic, there is as much oxygen at altitude as at sea level, its still 20.9%, what is different is the way the body absorbs it due to the partial pressure of the gas.
e.ghttp://www.boldmethod.com/images/learn-to-fly/aircraft-systems/oxygen-systems/cannula-wearing-large.jpg

[Mk 1]

Agreed!



Yet to be verified, but here's the report in NYT:
https://www.nytimes.com/2018/04/17/us/southwest-airlines-explosion.html?ribbon-ad-idx=4&src=trending&module=Ribbon&version=origin&region=Header&action=click&contentCollection=Trending&pgtype=article


Maybe all of that was unnecessary, but it sounds like not just flight crew but pax were trying to help out. If true, that deserves some credit.

Yes it does and perhaps in due course we will hear about the heroic actions that occurred inside the cabin.

I was however railing against the pilots actions being described as heroic. The captain and first officer did a very competent job in the cockpit, no doubt about it - and the cherry on top was Tammy's concern for her passengers after landing. She could have left the evacuation to cabin staff and emergency crews - but she took her time to re-assure passengers etc, that's class.

[Carbon Bootprint]

I've just rewatched it (season 1, episode 10). In their tests they couldn't get a crash test dummy to be sucked out of the plane, in any scenario.

However, they did blow out the window in a manner very similar to this one, and in the footage you can see how traumatic it would be for the passenger sitting next to it. Sucked out: no chance.However unpleasant the thought, for the record, it has happened: National Airlines Flight 27 (https://en.wikipedia.org/wiki/National_Airlines_Flight_27).One passenger, G.F. Gardner of Beaumont, Texas, was partially forced into the opening made by a failed cabin window, after it too was struck by engine fragments. He was temporarily retained in that position by his seatbelt. "Efforts to pull the passenger back into the airplane by another passenger were unsuccessful, and the occupant of seat 17H was forced entirely through the cabin window." The unfortunate gentleman's remains weren't located for two years, and it took another year to positively identify them.

[wiggy]

Any by the way just to be pedantic, there is as much oxygen at altitude as at sea level, its still 20.9%, what is different is the way the body absorbs it due to the partial pressure of the gas.

:confused:

there is as much oxygen at altitude as at sea level,

No there isn't.

Maybe it's a case of terminology but as understand it the partial pressure of oxygen (measured as a percentage) is the same at altitude as at sea level, but the actual amount of oxygen (as in molecules per unit volume/breath taken) is less at altitude.......

[ChicoG]

Leaving aside the oxymoron inherent in that statement, the suggestion that

is simplistic in the extreme, being based on the assumption that if a blade is going to let go it will do so the first time N1 reaches a certain value and not on some subsequent occasion.

It's particularly irrelevant in this case, given that the NTSB is already reporting indications of metal fatigue at the blade root.


"Last year, the engine maker and the Federal Aviation Administration instructed airlines to make ultrasonic inspections of the fan blades of engines like those on the Southwest jet. The FAA said the move was prompted by a report of a fan blade failing and hurling debris. A Southwest spokeswoman said the engine that failed Tuesday was not covered by that directive, but the airline announced it would speed up ultrasonic inspections of fan blades of its CFM56-series engines anyway.".

https://www.newsday.com/news/new-york/southwest-engine-victim-1.18129205

[darobstacraw]

Can anyone comment on what it would take to detect the type of fatigue that would cause a blade failure like this?
If you pointed a high speed IR camera at the front of the engine(s), would you perhaps see a different heat signature from the root of the fan blades?
In this age of Internet of Things where data is being so heavily collected from everything (especially jet engines) what metric would give you fore-warning of a failure of a fan blade?

[ktcanuck]

Can anyone comment on what it would take to detect the type of fatigue that would cause a blade failure like this?
If you pointed a high speed IR camera at the front of the engine(s), would you perhaps see a different heat signature from the root of the fan blades?
In this age of Internet of Things where data is being so heavily collected from everything (especially jet engines) what metric would give you fore-warning of a failure of a fan blade?

Eddie current and dye static testing can detect cracks. Acoustic emission can detect crack growth (not very practical on a fan blade!).

[FIRESYSOK]

Eddy current testing, ultrasound

[alphasun]

I am not in aviation engineering, but have edited aircraft manuals. One report raised a question in my mind.
A passenger reported that there was a lot of vibration after the main disintegration impact. i.e as the pilot was reacting.
Could this mean that the engine hub was still rotating or would it be connected to rapid manoevering?

[OldnGrounded]

@darobstacraw:

There are a number of processes for detecting metal fatigue that is not visible to humans, including ultrasound, eddy current, radiography, etc. In cases like this (fan blades) some version of ultrasound testing is probably most-used.

I can't post links (I usually read here, not write), but the Aviation Pros website has a quick introduction.

[Lost in Saigon]

I assume the un-named male First Officer was the Pilot Flying during the descent and initial approach, while Captain Tammie Jo Shults ran the checklist and the radio. (except when the FO responded to ATC clearing SWA1380 direct to Philadelphia)

On final, when they switched to the tower frequency, Captain Shults took over flying while the First Officer worked the radio.
(after landing the Captain went on the radio again)



EDIT: This one is better than the one I originally linked to:

#WN1380 Southwest Engine Explodes in midair and a Window Breaks!

[FIRESYSOK]

I am not in aviation engineering, but have edited aircraft manuals. One report raised a question in my mind.
A passenger reported that there was a lot of vibration after the main disintegration impact. i.e as the pilot was reacting.
Could this mean that the engine hub was still rotating or would it be connected to rapid manoevering?

Alright let’s use some common sense here. 5,000 rpm disc weighing hundreds of pounds just became completely unbalanced. Even if the fadec commanded a shutdown automatically, nothing happens quickly. And the engine would likely continue to windmill. Significant damage to wing leading edge, nacelle, etc. What kind of maneuvers do you think the pilots put on that would cause airframe vibration? If anything some soeedbrake for the emer descent. This used to be a professional forum.

[Pilot DAR]

As pointed out, the mask does not have to be fully over both nose and mouth.

Correct. The mask should be worn to cover the nose and mouth, but if mis worn as shown, it's still going to get the oxygen to the wearer.

To complete the thinking on this, it helps to understand that your average adult will take about 12 one to two liter breaths per minute. Of those breaths, 21% or so will be oxygen, and the rest the other components of the air, most nitrogen. While the overhead oxygen generator is providing near pure oxygen to the mask, that need and may only be 1/5 of the volume of air which the wearer would naturally like to inhale. So, if they inhale the rest of the non (or very low concentration oxygen) "around" the mask, the objective of providing the oxygen has been met. To this end, close examination of the "dixie cup" oxygen mask will show that in addition to a rather poor face fit, it actually has a rubber flapper valve for both in flow, and outflow. So, if a panicked passenger is pressing the mask tight to their face, those valves can open to assure that an adequate volume of air is being breathed in, in addition to the required oxygen.

But, yes, it would be nice if the passengers actually comprehended the passenger briefing, and wore the mask as it is designed to be worn!

[pax2908]

Certification somehow requires to demonstrate that separation one fan blade be contained ... here it looks like it was not ... was wondering if the certification process requires only one such successful test instead of a statistically significant number of blade release tests and/or recurrent such tests? ($$$)

[gums]

No, Wiggy, the partial pressure is the problem as well as less total oxygen.

At my mountain cabin the pressure is about 75% of sea level and the total amount of "air" is also about 75%. Since I have COPD, I am intimately familiar with these things. Also wore a nose hose in jets for 20 years, so have been thru explosive decomp and flying unpressurized as high as 40,000 feet on positive pressure, pure oxygen.
+++++
The ATC transcript illustrates an outstanding degree of professionalism. Can't wait to see the CVR.

On my serious structural damage approach I was not as adamant about the serious part and both approach and tower didn't really give me the priority they gave SW1380. Lesson learned, and you don't have to scream at them, heh heh. On my profile and the linked interview/bio, you can see the damage of my plane and might be able to see/hear the video of the approach.

Gums...

[JW411]

I am reading elsewhere on Pprune that Captain Tammy Shults was one of the US Navy's first female F-18 pilots. Anyone who can reunite an F-18 with a pitching carrier deserves my respect at least. She did a good job and so did the rest of the crew.

[Highway1]

Certification somehow requires to demonstrate that separation one fan blade be contained ... here it looks like it was not ... was wondering if the certification process requires only one such successful test instead of a statistically significant number of blade release tests and/or recurrent such tests? ($$$)

You are making the assumption that the fan bade wasn't contained - no evidence to support that so far.

[Herod]

gums.

Right about the partial pressure. Perhaps another way to explain it to the uninitiated. (Aeromed lectures a long time ago.)

Call the pressure of air at sea level 100. Oxygen then has a partial pressure of 20, sufficient to force it into the bloodstream. At about 35,000' the pressure of the air in total is only now about 20. 100% oxygen from an economy (non-pressure) mask is still 20, so OK. Above this it drops with altitude, necessitating pressure breathing to get it back up again. As I understand it anyway.

[climber314]

:confused:



No there isn't.

Maybe it's a case of terminology but as understand it the partial pressure of oxygen (measured as a percentage) is the same at altitude as at sea level, but the actual amount of oxygen (as in molecules per unit volume/breath taken) is less at altitude.......

"as in molecules per unit"

Correct!

[wiggy]

No, Wiggy, the partial pressure is the problem as well as less total oxygen.


Hi gums, like you having been through the joys of military aviation med training (British version), altitude chamber runs and (before my civvie days) used hoses attached to the likes of the F-4 :ok: through to the (mighty, noisy but unpressurised) Jet Provost Mk 3 :eek: I know that partial pressure of O2 becomes an issue, but I would certainly still take issue with the claim in the statement that kicked off this bit of the debate that the “amount” of oxygen is unchanged at altitude...

Anyhow above all this is a distraction from the body of the thread and I need to add my chapeau” to the crew in the SWA flight.

Rgds

Wiggy

[pax2908]

You are making the assumption that the fan bade wasn't contained - no evidence to support that so far.
Was only a question re. certification.

[DaveReidUK]

Was only a question re certification.

What part of

here it looks like it was not [contained]...

have we misunderstood ?

[Mad (Flt) Scientist]

A user on AVHerald posted a question which merits an answer from the pilots here:



It must be true that if this accident had begun on the ground, there could not have been injuries from cabin decompression.

Is there any merit in the argument that stressing engines to the max on the ground from time to time would be a good idea?

When operating flex takeoffs, there's a requirement to assure that max thrust is still available on the engine when(if) required. Traditionally that was done via requiring a full power (non flex) takeoff periodically (100 flights). Today, operators can also use trend monitoring programmes to keep an eye on engine wear and react before they would have failed the full piower check.

All of this however is intended to check that you can get full rated thrust without breaching ITT limits (the normal problemthat occurs first on a "worn" engine is failing to be able to do so); it was never seen as a check on fatigue life remaining. So by that logic, using trend monitoring in lieu of the full power check is entirely reasonable.

[Cows getting bigger]

hoss183, your pretty picture of two blokes with white moustaches. The manufacturer only 'certifies' those to 18000ft, which is just a bit different to 30000+ft.

[BARKINGMAD]

How many of todays 73', e-jet and small 'bus drivers get into the cowling and stroke every one of the blades on each engine on the leading edge to check for new FOD nicks?

Maybe that's how I got my posting name and got laughed at by the rest of my colleagues but once the daily servicing has been signed off by base engineer, then flight crew are the only ones to supposedly check for potential crack initiators on subsequent sectors.

Oh, and before the flak starts flying, I ensured I didn't leave any little bits of FOD in the intake area.

But I am forgetting, it wasn't taught by the airline's training department, just a hangover from associating with those wonderful flight engineer chappies...

I must get out more often. Tin hat donned and await incoming......:(

[golfbananajam]

Having listened to the audio a couple of time now I'd like to add
1. My condolences to the family of the deceased PAX
2. My congratulations to the crew for a professional job, without panic, in getting the plane to the ground without further incident
3. My congratulations to the ATC staff whose "you tell me what you want and I'll clear it" attitude is a welcome breath of fresh air showing what common sense professionalism can achieve when it's needed

[PAXfips]

VASAviation made a multi-channel ATC recording, including subtitles and radar overlay. Very professional handling in the cockpit, I think, as a PAX.

https://www.youtube.com/watch?v=cnSizWZVyD4

[Brian W May]

Post #191 Barking . . . absolutely agreed.

No incoming from this direction . . . what a tragedy. That's one engine you CAN actually see, however when it's raining all of us have been guilty of a cursory look on occasion . . .

Before ANYBODY infers I'm criticising the crew . . . THINK AGAIN. No such inference, they did really well.

[Smott999]

Props to the Captain and FD crew for such a high level of professionalism.
Props and thoughts as well to the CC for working to resuscitate a gravely injured passenger, must have been horrific.
Props to the passengers who ignored their own safety to bring the passenger back onboard and block the hole.

A lot of very fine performances on this day, so sad that a life was lost.

[lomapaseo]

With the SW 3472 incident in 2016, plus the SW 438 incident in 2007, and now this, I think the focus of attention needs to be as much on the cowl as the blade. In two (perhaps all three) cases the root of an N1 fan-blade failed (due to fatigue on the 2016 incident) and the blade separated.

But in all three cases the blade appears to have missed the containment ring and struck the cowl instead, causing a complete failure of the cowl, and all the attendant risks with all that material flying off into the slipstream. If you look at the N1 containment ring on the recent incident, it appears to be untouched all the way around. But the cowl took the full force of the departing blade, and disintegrated.

The N1 blade is under considerable aerodynamic forward pressure in flight, and will naturally spring forwards when released. But in static testing for cerification the blade still seems to hit the containment ring. Yet here it appears that the blade moved forward enough to miss the containment ring, and strike the cowl. Perhaps an engineer on this board might suggest why that might be. Why would the forward speed of the aircraft have any effect on the trajectory of the departing blade?

ST

Just for general understanding .. the released blade loses significant aero forces such as lift as soon as it is released. Given that it now contacts the engine casing within milliseconds the forces acting on the blade tip are friction against tangential inertia. Like a downhill skier the blade tip follows the line of lowest friction which skate it forward of the plane of rotation.

I was struck by the excellent quality of the referenced NTSB Walk-around video and the observation that the engine itself closely matched the manufacturer's successfully certified blade out test.

The secondary events immediately following the loss of the blade now become of primary importance to resolve.

[OldnGrounded]

>>> Like a downhill skier the blade tip follows the line of lowest friction which skate it forward of the plane of rotation.

Yes, exactly. Perfect analogy succinctly explaining the physics.

>>> The secondary events immediately following the loss of the blade now become of primary importance to resolve.

Yup. Given the possible consequences, it appears that better containment of an FBO is required forward of the containment ring.

Also, another chapeau to the crew, ATC and the pax who immediately stepped forward to assist. Cool, collected and competent, across the board. Gold stars to everyone.

[Concours77]

lomapaseo. Always a reliable source of engine data, I’d be interested in a description of the actual path of number thirteen such that a ‘minds eye’ picture could occur?

As in, with a spiral track through space whilst attached to the rotor, how long could this radial trajectory sustain after root failure? The cowl looks “scrubbed clean” at the containment ring forward. Did the blade complete at least one revolution post release with energy enough to remove all the “crumple cowling”?

[Retired DC9 driver]

How many of todays 73', e-jet and small 'bus drivers get into the cowling and stroke every one of the blades on each engine on the leading edge to check for new FOD nicks?

Well I used to. Except on the 767, if it was parked with a strong tailwind, and fan turning over at high speed !
Once we had a 319 (CFM) that had landed with previous crew in icing conditions. I asked my F/O, doing the walkaround to check the fan blades for ice buildup, after inbound crew taxied to gate.
He found 1/8 inch of ice on back of the N1 blades ! Maintenance had to bring in a ground heater to melt ice off fan blades, before engine start.

[DaveReidUK]

Was the initial NTSB walkaround already posted?


Post #109.

NTSB walkround video:

[JPJP]

I assume the un-named male First Officer was the Pilot Flying during the descent and initial approach, while Captain Tammie Jo Shults ran the checklist and the radio. (except when the FO responded to ATC clearing SWA1380 direct to Philadelphia)

On final, when they switched to the tower frequency, Captain Shults took over flying while the First Officer worked the radio.
(after landing the Captain went on the radio again)


Other way around - The PF would be working the radios, and the FO would be running the checklist. If the FO answered a radio call it may indicate that the CA was communicating with the FAs or making a PA. On approach the roles may return to normal, with the majority of checklists complete.

Obviously, it’s the CA perogative if she wants to run the checklist/manage.

[Yancey Slide]

I doubt it. If the pax was in line with the axis of the fan there would have been a high energy penetration. Being that the failed window was behind the wing, its likely that it was an unlucky strike of some debris falling rearwards.
The report is she was out of the window up to her waist, and the injury likely occurred flailing in the slipstream against the fuselage.

Something like https://en.wikipedia.org/wiki/British_Airways_Flight_5390 ?

[pax2908]

What part of

"looks like it was not"

have we misunderstood ?

I don't know for sure.

However somebody earlier wrote "Fan blade 13 missing at hub with evidence of metal fatigue".
This seems to indicate (at least as a possibility) the root cause of this event was a fan blade broken.
After this, whether the blade itself remained "contained" but something else was triggered (some other piece went off as a result) which in turn caused cabin damage etc, in my opinion is immaterial.

I stand to be corrected!

[Lost in Saigon]

Other way around - The PF would be working the radios, and the FO would be running the checklist. If the FO answered a radio call it may indicate that the CA was communicating with the FAs or making a PA. On approach the roles may return to normal, with the majority of checklists complete.

Obviously, it’s the CA perogative if she wants to run the checklist/manage.

The Captain was working the radios before they lost the engine. I guess she may have taken control and let the FO run the checklist. We'll have to wait for the CVR transcripts to know for sure.

[ex-EGLL]

You can’t, this was the number 13 blade and there are only 24 blades....(/s)
#1 per chance?

[lomapaseo]

This seems to indicate (at least as a possibility) the root cause of this event was a fan blade broken.
After this, whether the blade itself remained "contained" but something else was triggered (some other piece went off as a result) which in turn caused cabin damage etc, in my opinion is immaterial.

I stand to be corrected!

Lawyer speak

"had it not been for..."

But in aviation we work in balancing risks so the regulatory aspects recognize that nothing is perfect among all the systems including their human maintenance and operation.

Thus the operating words are "in spite of"

precautions need be taken to etc. etc.

[hans brinker]

#1 per chance?

See the /s?

[foxcharliep2]

Props to the Captain and FD crew for such a high level of professionalism.
Props and thoughts as well to the CC for working to resuscitate a gravely injured passenger, must have been horrific.
Props to the passengers who ignored their own safety to bring the passenger back onboard and block the hole.

A lot of very fine performances on this day, so sad that a life was lost.

Thank you for your comment, my thoughts as well.

[tdracer]

was wondering if the certification process requires only one such successful test instead of a statistically significant number of blade release tests and/or recurrent such tests? ($$$)
Assuming it passes, the complete engine fan blade out test is only run once - the test is horribly expensive (it basically destroys the test engine, plus it's heavily instrumented with much of the instrumentation also effectively written off, plus all the 'normal' costs of doing an engine test). They often do rig tests - basically an isolated fan - to test out certain aspects to make sure it'll work when they do the whole engine test. The test is done at redline N1, which is normally considered to be the worst case condition.
The only time I know of where they repeated the test was on the original GE90 - although the blade was contained, the resultant vibrations caused a bunch of other stuff to fail (including the inlet coming off at the attachment flange). Although they tried to convince the Feds that they could show analytically that they'd fixed all the failures, the FAA made them repeat it. Scuttlebut was the cost of repeating the test was north of $40 million.

All that being said, I've not seen anything that says the fan blade was uncontained. Clearly the inlet structurally failed, but the why is unclear.

[CONSO]

hey tdracer
All that being said, I've not seen anything that says the fan blade was uncontained. Clearly the inlet structurally failed, but the why is unclear.

Suggest you check post by silverstrata

https://www.pprune.org/10122411-post125.html

for a plausible explanation as to path of missing blade

which would probably be enough to whack a chunk off of cowl/inlet

[Lonewolf_50]

I'll be flying up to Reagan Airport next month on Southwest, with the Missus. I advised her that as usual, she can have the window seat.

If looks could maim, they'd have to put me into a laundry basket. This news story has quite unnerved her.

Me, understanding reliability and probability, am now the proud window sitting passenger of we two on a trip for the first time in years.

[pilotmike]

lomapaseo. Always a reliable source of engine data, I’d be interested in a description of the actual path of number thirteen such that a ‘minds eye’ picture could occur?

As in, with a spiral track through space whilst attached to the rotor, how long could this radial trajectory sustain after root failure? The cowl looks “scrubbed clean” at the containment ring forward. Did the blade complete at least one revolution post release with energy enough to remove all the “crumple cowling”?

The only force that kept the blade continuing its circular path around the shaft was the 'inward' centripetal acceleration force while it was still attached.

Once the blade has failed at the root, that centripetal force has gone, there is no further acceleration force acting on the blade, and its trajectory immediately becomes linear, directly tangential at the moment of release.

Of course, the swirl of air, as well as possible impact by the other blades which are still rotating might well cause it to have some rotational path, and the momentary residual forward force on the blade as well as the 'pitot' force of incoming air will complicate the picture further.

In any case, my main point is that there is no inherent mechanical force or tendency for the liberated blade causing "this radial trajectory [to] sustain after root failure" as you seem to suggest.

pm

[RatherBeFlying]

The role of the containment ring is to prevent a detached fan blade from flying straight off. To illustrate the damage potential, recall the DC-6 accident at Burbank where a departed prop blade passed through the fuselage and hydraulic lines before damaging the number 2 engine which failed not long after. https://aviation-safety.net/database/record.php?id=19760208-0

The errant blade will lose energy contacting the containment ring, possibly more than once, but may gain energy from the remaining fan blades - all within a fraction of a second before it exits the cowl in whichever direction not blocked by the containment ring.

[Gegenbeispiel]

[QUOTE=pilotmike;10123195]The only force that kept the blade continuing its circular path around the shaft was the 'inward' centripetal acceleration force while it was still attached.
Once the blade has failed at the root, that centripetal force has gone, there is no further acceleration force acting on the blade, and its trajectory immediately becomes linear, directly tangential at the moment of release.

Yes, but:

1. We need to be clear this is happening in airframe co-ordinates.

2. At the moment of blade departure, there will be a significant pressure drop (as before, when the blade was attached) from the back to the front of the blade. Thus, I'd expect the blade's departure path to somewhat behind tangential, opposite the direction of rotation and somewhat towards the nose. That's likely how the blade got around the cowl leading edge to smash the window.

On a different topic, I see reports of a hydraulic failure but evidence of that in the ATC recording. Surely the crew would have reported that to ATC if it did happen?

Well done, crew!

[averow]

Exactly this....took me a while to wrap my head around this. The percentage of oxygen in air does NOT change with altitude, but the amount does. Air at sea level has the same percentage of oxygen at 20k feet, 30k feet etc. However air pressure drops with altitude, as do the absolute numbers of molecules on nitrogen, oxygen, argon, etc. The concept of "partial pressure" explains this more scientifically but is not terribly intuitive. There are two ways to fix this: increase the inspired fraction of oxygen above 21%, thereby making more molecules of oxygen available, OR force air at higher pressure into the lungs making the pressure (and amount) of oxygen more like breathing at sea level. The first method can help up to a certain altitude and is what happens with the loosely fitting masks that drop down for passengers. Certainly OK for a short period, say to go from 30K feet down to 10K. For the pilots it makes more sense to have tightly fitted masks connected to pressurized air (or air enriched with additional O2) of unlimited supply. That way they can maintain near normal intake of oxygen while flying the plane. Interestingly enough climbers in the Himalayas suffering from altitude sickness can be supported by pressurizing them in a Gamov bag: basically a foot pressurized habitat that is pumped full of ambient air so that the patient receives 21% O2 at higher than ambient pressure.

[Highway1]

2. At the moment of blade departure, there will be a significant pressure drop (as before, when the blade was attached) from the back to the front of the blade. Thus, I'd expect the blade's departure path to somewhat behind tangential, opposite the direction of rotation and somewhat towards the nose. That's likely how the blade got around the cowl leading edge to smash the window.



There is no evidence that it was the blade that smashed the window - you are jumping to assumptions.

[WingNut60]

In any case, my main point is that there is no inherent mechanical force or tendency for the liberated blade causing "this radial trajectory [to] sustain after root failure" as you seem to suggest.

pm

Seems reasonable, trajectory after separation would certainly be chaotic.

But this does also assume instantaneous separation under tension (typical fatigue failure).
However the blade in operation is subject to considerable bending and twisting moment, cyclic with every engine power change or every time that the load on the blade changes. This could (is likely) to see crack propagation originating along the trailing edge surface, the surface under tension when the blade is bent forward.
It is conceivable that the final failure is not instantaneous, no matter how quickly it occurs, but occurs over the course of some part of rotation or full rotations of the fan.

Possible that final separation might occur progressively with the leading edge surface failing under combined bending / tensile load, at which time the tip of the blade could well be "hinged forward" to some extent.

Such a failure would be evidenced by plastic deformation along the leading edge fracture zone.

In routine inspection, is the focus on the trailing edge root area?

[tdracer]

hey tdracer
.

Suggest you check post by silverstrata

https://www.pprune.org/10122411-post125.html

for a plausible explanation as to path of missing blade

which would probably be enough to whack a chunk off of cowl/inlet
Conso, while there is a first time for everything, we did a lot of investigations of fan blade releases over the years. In some of the events, there was some low energy debris that did damage forward and aft of the fan containment ring (in most cases it didn't penetrate the acoustic lining), but never any indication of high energy debris missing or penetrating the containment ring.
Again, I've seen no evidence that the fan blade was uncontained or that was what took out the window. My personal theory is it was a large chunk of the disintegrating inlet that hit the fuselage. The question remains why the inlet broke up. The inlet is designed to withstand the aero loads inflight, and it's designed to withstand the forces (mainly vibration) from a fan blade out. It appears that perhaps the combination of those two loads was not adequately accounted for.

[DType]

WN60, I think I sort of remember balancing a blade so that the SLIGHTLY offset CofG counteracted the aero forces, at a specific speed, etc., but it's all a very long time ago.

TDR, thanks for your measured, informed and intelligent contributions.

[Gegenbeispiel]

tdracer: >"I've seen no evidence that the fan blade was uncontained"

The NTSB has stated that fan blade 13 is missing. That's not simply missing from the hub, it's gone and they cannot find it. To me, that's uncontained.

Did you mean "no evidence of high kinetic energy blade departure"?

[OldnGrounded]

@WingNut60:

>>> It is conceivable that the final failure is not instantaneous, no matter how quickly it occurs, but occurs over the course of some part of rotation or full rotations of the fan.

[. . .]

>>> Possible that final separation might occur progressively. . .

Yes. In fact, however fast it may occur, it almost certainly is progressive. Very short time periods are still time periods.

Also, as has been pointed out, this failure didn't occur in a vacuum or on a fan that was motionless (except for rotation) with respect to surrounding structures. It took place at speed, on an aircraft engine moving, to various degrees, along multiple axes.

Taken together all of the forces likely to have been in play would presumably have resulted in the separated blade moving forward and along a(n at least somewhat) radial path.

Regardless of the above, it certainly seems that serious consideration should be given to the containment capability of the inlet cowl.

[flymesome]

I must give my props to the crew for their handling of the situation. But I have a few questions.

1) As the story has unfolded, I can assume that the crew first received the Engine Fire indications with Fire Warning going off. As they were still climbing (or maybe cruising), first thing they would be doing is Engine Fire or Engine Sever Damage or Separation Checklist memory items. But the cabin was punctured and they had a rapid depressuzation coming. If the cabin altitude warning horn sounded while they were doing the Engine Severe Damage memory items, does that mean that they have to hold checklist and continue with the Rapid Depressuzation memory items?

2) We didn't have the option of choosing between Flaps 15 and any other Flap setting on our QRH in the One Engine Inoperative Landing Checklist. Does planning a Flaps 5 landing raise the question of legality in terms of crew training?

I'm just curious.

[ph-sbe]

The NTSB briefing makes it clear that the decision to deploy only Flap 5 for the landing was due to consideration of potential controllability issues.


Which was one of the smartest decisions made by the crew. Remember the ELAL1862 incident where slats were damaged by the engines being ripped off. This may very well have produced a similar scenario of uncontrollability at lower speeds while deploying flaps/slats.

Excellent crew (both flight and cabin), and soooo sad about the loss of life.

[Highway1]

tdracer: >"I've seen no evidence that the fan blade was uncontained"

The NTSB has stated that fan blade 13 is missing. That's not simply missing from the hub, it's gone and they cannot find it. To me, that's uncontained.


But that isn't what the design designation means. The containment ring did its job and prevented the separated blade from exiting the engine at 90 degrees. The investigation now is to discover why there was a catastrophic failures of the nose cowl assy.

[Matt48]

In the photo I have seen there are three people wearing the mask and they are all wearing it wrongly. The right reaction to this is to ask why and what can be done to improve the situation. Is it the design of mask, the training/communication or something else? What is the typical response? What factors affect it? Ideally the shape would be such that to wear it correctly is natural and comfortable and incorrectly difficult and uncomfortable. Is that possible? Can their be picures or diagrams on the mask? Should the safety briefing be changed?

Calling for a Darwin award for someone in an unexpected situation not of their making who tries but fails to follow safety instructions is more than harsh.

Given that there were NO reports of incapacitations or fatalities caused by the incorrect wearing of the O2 masks, maybe it's time to just let it go.

[tdracer]

tdracer: >"I've seen no evidence that the fan blade was uncontained"

The NTSB has stated that fan blade 13 is missing. That's not simply missing from the hub, it's gone and they cannot find it. To me, that's uncontained.

Did you mean "no evidence of high kinetic energy blade departure"?
Highway1 beat me to it, but the definition of 'uncontained' is engine parts exciting tangentially out of the engine nacelle. Bits that come out the nozzle are, by definition, not 'uncontained'. Furthermore, bits of engine that make it through the engine case or fan containment ring but don't penetrate the nacelle are still considered 'contained' (e.g. engine parts that come tumbling out when they open up the nacelle are considered contained).
So, a turbine blade coming out the side of the engine is an uncontained failure, a broken turbine blade that exits out the tailpipe isn't.

[hunbet]

tdracer: >"I've seen no evidence that the fan blade was uncontained"

The NTSB has stated that fan blade 13 is missing. That's not simply missing from the hub, it's gone and they cannot find it. To me, that's uncontained.

Did you mean "no evidence of high kinetic energy blade departure"?

During the NTSB briefing that I watched a little while ago, the Chairman stated that they had the lower 1/3 of the blade. After the blade was liberated it fractured again and the outer 2/3 rds is missing.

"Fan blade separated in 2 places.
5 p.m.: There was a fatigue fracture where the #13 fan blade would have gone into the engine. That was the initiating event that caused a secondary failure of the jet engine."

News media is concentrating on the fact the plane landed at higher than normal speeds and the entire briefing isn't on youtube yet.

[chucko]

During the NTSB briefing that I watched a little while ago, the Chairman stated that they had the lower 1/3 of the blade. After the blade was liberated it fractured again and the outer 2/3 rds is missing.

"Fan blade separated in 2 places.
5 p.m.: There was a fatigue fracture where the #13 fan blade would have gone into the engine. That was the initiating event that caused a secondary failure of the jet engine."

News media is concentrating on the fact the plane landed at higher than normal speeds and the entire briefing isn't on youtube yet.


The NYTimes is quoting Sumwalt in today's briefing as saying that a fan blade was missing from the No. 2 engine as well.


...and that statement has since disappeared from the on-line edition of the Times.

[clark y]

Matt48, well said.
For us, this would be similar to studying the escape routes of the hotels we stay at on overnights. One day it might save your life.

As for the mystery blade, looking at the remaining fan, my guess is it went out the front or through the inlet cowl. There seems to be very little damage to the remaining fan. One adjacent blade bent? The previous incident showed massive damage. Either the blade went forward or it slid cleanly between the remaining blades and out the back of the engine.
Something caused the cowl to self destruct. Blade, vibration, what ever, hopefully the investigators can learn what so it can be prevented in future.
As for the window, something hit it. Once again, I'll leave it to the investigators.

Finally, great job by the crew on a really bad day.

[Matt48]

Matt48, well said.
For us, this would be similar to studying the escape routes of the hotels we stay at on overnights. One day it might save your life.

As for the mystery blade, looking at the remaining fan, my guess is it went out the front or through the inlet cowl. There seems to be very little damage to the remaining fan. One adjacent blade bent? The previous incident showed massive damage. Either the blade went forward or it slid cleanly between the remaining blades and out the back of the engine.
Something caused the cowl to self destruct. Blade, vibration, what ever, hopefully the investigators can learn what so it can be prevented in future.
As for the window, something hit it. Once again, I'll leave it to the investigators.

Finally, great job by the crew on a really bad day.

Been wondering if the damage to the forward part of the cowl could be a result of some damage to it from the departing blade, magnified by a severe shaking from the immediate imbalance at near redline N1 speed plus aerodynamic loads at 4-500kts. Any takers ?

[Guptar]

Many years ago during my commercial training i was shown a blade off video of a test engine where the impact of the blade against the fan case cause a small but dense component mounted on the outside of the engine to fly off at high speed much like a cueball hitting an 8ball. Slomo video shows the outside of the engine case flexing significantly durng the bladeoff test. Could this be a possibility?

[PineappleFrenzy]

Been wondering if the damage to the forward part of the cowl could be a result of some damage to it from the departing blade, magnified by a severe shaking from the immediate imbalance at near redline N1 speed plus aerodynamic loads at 4-500kts. Any takers ?

I think we've beaten this dead horse enough. A fan blade departed and bad things happened. The NTSB will tell us exactly what happened, and why.

[Matt48]

While some passengers sobbed and screamed, others took off their oxygen masks and proceeded to rescue and apply first aid to the injured woman, that is my definition of 'hero'.

[ACMS]

+1 Matt48.........

[freshgasflow]

An earlier post mentioned that while engines are designed to contain blade separation, engines are not designed to contain disc failure. As a SLF i would be grateful if someone will explain what are discs in an engine. A link to a diagram would be great. I googled it and could not find a diagram showing engine discs. I know this must be a very basic question for those in the know, but it would help us , SLF , to follow things. Thank you.

[tdracer]

An earlier post mentioned that while engines are designed to contain blade separation, engines are not designed to contain disc failure. As a SLF i would be grateful if someone will explain what are discs in an engine. A link to a diagram would be great. I googled it and could not find a diagram showing engine discs. I know this must be a very basic question for those in the know, but it would help us , SLF , to follow things. Thank you.

At a very basic level, the 'discs' are what hold the fan, compressor, and turbine blades - the 'hub' of the wheel if you will. The fan disc is massive - several feet in diameter on most turbofan engines - and needs to be heavy duty enough to not only restrain the centrifugal force of the (relatively) large and heavy fan blades spinning at several thousand RPM, but also the thrust loads since the fan produces the majority of the thrust on modern engines. A fan disc failing is seriously bad news - a piece several feet across with massive rotational energy. We have a saying 'where does 1/3rd of a fan disc go? Anywhere it wants to" Google 'Sioux City DC-10' to see what can happen when a fan disc lets go.
The compressor and turbine discs are similar but smaller (some newer engines use a compressor 'spool' - a cylindrical piece that holds the compressor blades for multiple compressor stages, replacing several individual compressor discs). Since they are smaller, compressor/turbine discs have less mass than a fan disc, however the high pressure section of the engine spins far faster than the fan (upwards of 10,000 rpm - sometimes higher than 20,000 rpm depending on the engine) so they also have massive rotational energy.

A burst disc - with all it's energy - will go almost perfectly tangential to the axis of rotation (cert requirements give a +/- 10 degree cone for burst disc debris, vs. +/- 30 degrees for 'lower' energy debris such as blades.

Does that help? Teaching isn't my forte :hmm:

[RodH]

Whilst the crew did a very good job just as they and all of us are trained to do I do think their R/T procedures were very lacking.
There were quite a few queries as to the status of the flight from ATC.
Why did the Capt. not simply give a mayday call as it was most appropriate. Maybe not initially but when she found what had happened there was still confusion with ATC as to the aircraft's status.
After listening to a lot of " Live ATC " on you tube it seems that in the USA the terms Pan or Mayday are hardly ever used and because of that there is a lot of verbal with ATC as to aircraft's status.
Is it not an International Standard to use Pan or Mayday?
Apparently not in the USA.

Anyway the crew , cabin crew and some pax did a very fine job so well done to them!:confused::confused::confused::confused::confused:

[DaveReidUK]

Whilst the crew did a very good job just as they and all of us are trained to do I do think their R/T procedures were very lacking.

Yes, it's almost as if they had given more priority to Aviating and Navigating ...

[ExSp33db1rd]

Mayday ?

M'aidez - Help me.

Yes, they certainly needed help, nearest available, ground support once down, ATC giving them an interrupted approach, but ... they achieved that anyway, and ..... we weren't there.

DaveReidUK has put it in perspective, they got their priorities right, or when in doubt ....Fly The Aeroplane.

[RodH]

Yes, it's almost as if they had given more priority to Aviating and Navigating ...

Sure they did that but there was a lot of conversation as to their status so why not a May Day call which puts it all in a better perspective!

[sleeper]

I think it's more of a culture difference. In the US you "declare an emergency", in the rest of the world it is a mayday. Like rcsa said in their (US) mindset mayday is the final chapter, ie you're going down.

[thelearner]

An earlier post mentioned that while engines are designed to contain blade separation, engines are not designed to contain disc failure. As a SLF i would be grateful if someone will explain what are discs in an engine. A link to a diagram would be great. I googled it and could not find a diagram showing engine discs. I know this must be a very basic question for those in the know, but it would help us , SLF , to follow things. Thank you.

Also SLF - flew more in Helicopters than airliners, and experience working with aero engines driving compressors and power turbines. Couple of links below that may help you.

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

https://www.youtube.com/watch?v=1Vzbd3kO7kU

The blades in the video are much smaller than the ones used on the large fan which failed on this flight. (scroll down to major components in wikipedia page to see this)

Echo other thoughts - incident handled extremely well by crew and PAX who went to assist. Thoughts with the family of the deceased lady. Terrible time for them.

[hikoushi]

Because 'Mayday!' means "I'm going down, right here, right now, and there's nothing I can do about it'. Which this a/c wasn't - it was going to Philly, under controlled flight.

And because aircrew are trained to not make a drama out of a crisis.

In the USA we "declare an emergency". "Emergency" is a correct, official radiotelephony term used in both the ATC handbook and AIM. This gives us priority handling. It does not necessarily (though in practice does usually) automatically give you ARFF response. Note she also asked them specifically to "roll the trucks" which while most definitely incorrect per ICAO, would not be misunderstood by any ATCO in the country. An ATC controller will never ask you "if you are MAYDAY" but will ask you "are you declaring an emergency?" if you have not said so but request priority for whatever reason. If you say "I am single-engine" or any of a number of similarly severe scenarios, they will not burden you by asking but simply understand the implications, give you assistance, and "declare an emergency" to their supervisors on your behalf.

Yes MAYDAY would be the technically correct ICAO term (and yes it is also recommended in the AIM right after it describes the normal, more direct and informal way to communicate in a distress condition) but as mentioned it would be understood in the USA to imply that your situation is, to some degree, out of control. It is commonly understood that if a non-US carrier uses the term "MAYDAY" that they are saying the same thing that we mean by "declaring an emergency". It is also understood that "emergency" declaration means nothing outside of the USA, and that if we need priority handling elsewhere "MAYDAY" is the word to use.

However if lack of use of the word "MAYDAY" is the only criticism we can throw at this American domestic crew operating in American domestic airspace, let's just shut up and say good job.

Weren't there some people on here saying the same thing a couple days after the Miracle on the Hudson? Bet they were shocked when the CVR recording came out and Sully's "MAYDAY" was there after all!

[Heidhurtin]

Question from a non-pilot, feel free to move if it's the wrong forum.
I know there is a maximum single-engine height but assume that if an engine is lost, descent to this height would be a (relatively) gentle business, whereas an emergency descent due to loss of cabin pressure would be a much more rapid affair.
Would it be normal to tell ATC you were depressurised and descending rapidly, rather than simply that you were single-engined and descending?
No criticism intended - I've dealt with a few "holy sh#t" moments myself and after listening to the recording am reassured by the calm professionalism of crew, ATC and the emergency responders.

[wiggy]

but assume that if an engine is lost, descent to this height would be a (relatively) gentle business, whereas an emergency descent due to loss of cabin pressure would be a much more rapid affair.

Might be, might not be..if you have lost cabin pressure and structural integrity is in doubt you might contemplate a relatively gentle descent, rather than diving height off at high speed.

As for comments about R/T calls ... having had a quick listen to the archived feeds provided by others earlier in the thread I personally had ended up assuming some of the early calls that one would perhaps have expected to have been made when this all unravelled approaching top of climb were missing from the record. Certainly some of the exchanges you can hear are remarkably low key and will be interesting to see the transcripts.

[Cloudtopper]

Considering the gravity of this situation , 2 serious failures and memory actions accordingly plus a flap non normal checklist - landing with flap 5.

Theres no doubt about it , they managed the situation quiet well looking at the outset.

The ATC commucation was a little amateur in places . Perhaps a bit more force - personally i would of starting with a MAYDAY . Get the point across .

Did ATC speak a little too much - Much Slang?

The non normal checklist calls for a descent to 10000 during a rapid descent - why would they accept 11000 as per audio .

The rate of descent from 10K to circuit alt - how high ROD .

I also saw a bank angle of close to 45 recorded. This would imply the aircraft was close to an upset condition or very close to approaching one

Lastly . Regarding the earlier career of the captain flying for the US navy , should this imply that a non navy trained airline pilot is unable to carry out the above manoeuvres in a safe fashion - The media unfortunately appear to snowball this and quite often refer to this accident as a single pilot ops .

Significant investigative effort should also be placed on examining the
procedures and why the airline has had a similar occurrence 2 years back .

Out .

[pax britanica]

Captain certainly was extremely calm but then her years in the cockpit of an F18 doing stuff like night carrier landings would mean that while this was not exactly a walk in the park it probably wasnt the most frightning experience of her career.

The ATC tapes certainly show a very calm professional teamwork between ground and flight deck with a lot of quick thinking by ATC to give her a non standard visual approach into Philidelphia.

Humans 2 Automated FD and ATC Nil on this one, yes?

[Herod]

Flymesome.
We didn't have the option of choosing between Flaps 15 and any other Flap setting on our QRH in the One Engine Inoperative Landing Checklist. Does planning a Flaps 5 landing raise the question of legality in terms of crew training?

As I recall. you are right. 15 flap on one engine. However, there are times when a command decision calls for operation outside SOPs. That decision was made here, and I would suggest it was the right one. Successful outcome.

[PEI_3721]

Flymesome, you should always have options. QRH/SOPs are guidance; it’s up to you to select the most appropriate option for the situation, which may not be covered by documentation.
Forget the legalities; if you choose a justifiable option then there is a defensible case - for events at that time, and not based on evaluation after event or with hindsight.
In this instance, with wing leading edge/ slat damage, a ‘good’ option is to leave configuration as it - the aircraft is flying and still controllable. cf MD 80 tail trim accident.

[deadheader]

ICAO recommends the use of standard "PANPAN" and "MAYDAY" calls instead of "declaring an emergency" as failing to use non-standard phraseology has previously resulted in confusion and aircraft handling errors:

https://www.hkatc.gov.hk/HK_AIP/aic/AIC21-12.pdf

https://www.skybrary.aero/bookshelf/books/115.pdf

[megan]

Sure, I listen to the brief.

https://scontent.fadl1-1.fna.fbcdn.net/v/t1.0-9/30716019_10211707830994061_1703516321299888695_n.jpg?_nc_cat =0&_nc_eui2=v1%3AAeG5j-O3TILMB8IBk8U01UXCGiy8nFjueAzcpbDS3hvZu_E88TnI14CmsuDl4Zz3Lo et9-Sw9Ivs5NrwY-UCWIas8uRZs9UxFQeJYOuZdO2gpg&oh=df3f05b8d49af592dcdc1919e472b393&oe=5B660FE3

[bizdev]

For info - although a bit of thread drift - one of the very many cowling release incidents happened to an A320 Airtours aircraft out of LGW. The departing cowl took out an outer pax window but in this instance did not cause a depressurisation as the inner pane remained intact. Only reason for mentioning this is that it may not have been the exiting fan blade that hit the window (albeit that this was not the same aircraft type)

[RAT 5]

F5 with LED's at EXT was an understandable choice. When the Qantas A380 blew one, I also believe they did some handling checks. I presume that included some flap selections, but I can't remember all the ACI program details.
I wonder if a F5 election at 10,000 would be a good idea to confirm, before finals, that it was not going to cause control problems.
I'll be interested to hear how soon after the engine fire indication, i.e. the first 'attention- getting startle item', that the depressurisation warning pinged. The engine shutdown = immediate descent from FL32.5 anyway and the memory items being taken care of as the descent is being set up: then ping goes the pressurisation. Wow, that is a can of worms that not even the nastiest TRE would dream up in an RST sim. I'm glad there was more than a few years experience up front to deal with this. It would have been a real team effort as they bounced around checklists from Recall and had to include ATC.
I would have expected the broken window to create an explosive decompression, but it is a small opening. That will also be interesting hear about. Thus was it a MMo descent or same speed? I wonder how suction changes with IAS.

[infrequentflyer789]

Latest from the NTSB is now on youtube:

https://www.youtube.com/watch?v=EL5eMVGz5gk

Some interesting info on the window - they have found no trace of window material inside the aircraft. He didn't conclude anything from this, but I would suspect it points away from window being shattered by high energy impact (ie. the blade) and towards the window or frame being cracked by blunt impact from other debris and then blown out. From the photos we have the frame looks to me to be pretty intact though.

[M.Mouse]

In the video the speaker says the cabin altitude warning goes off at around 13,500'? Is that correct. My experience of Boeings is that the warning sounds at a cabin altitude of 10,000' and the masks will drop automatically at 13,500'. Is the B737 different?