News Accident: Southwest B737-700 N766SW near Pensacola, FL catastrophic engine failure

[dbeachy1]

From the article here:

A Southwest Airlines Boeing 737-700, registration N766SW performing flight WN-3472 from New Orleans,LA to Orlando,FL (USA) with 99 passengers and 5 crew, was climbing through FL310 out of New Orleans, about 80nm west of Pensacola,FL (USA) when the front section of the left hand engine (CFM56) separated, debris impacted and punctured the left side of the fuselage causing a loss of cabin pressure. The crew diverted the aircraft to Pensacola for a safe landing on runway 17, the aircraft vacated the runway and taxied to the apron with emergency services following the aircraft. There were no injuries, the aircraft sustained substantial damage.

Ouch...

 

[Ripley]

Finally, a happy ending one!

 

[Urwumpe]

That isn't exactly what I want to see when I look out of the window....

 

[Quick_Nick]

So what you're saying is... the front fell off?

That isn't exactly what I want to see when I look out of the window....

Or a new window that wasn't there before!

 

[Artlav]

So, the ten million dollar question is whether the debris all went outwards or some of it fell through the engine.

Hm, is fuselage damage like that repairable or not?

 

[Urwumpe]

So, the ten million dollar question is whether the debris all went outwards or some of it fell through the engine.

Hm, is fuselage damage like that repairable or not?

The pipe on top looks like it sheared off in one large piece and then followed the airflow.

And yes, it should be repairable for a old plane like 737. Such damages also happen on a smaller scale by clumsy airport workers. Modern carbon fiber hulls would be a total loss after such a damage.

 

[N_Molson]

Congratulations to the crew for their calm and great airmanship. Looks a bit like a bomber returning from a flakky bombing run on Germany during WWII :blink:

 

[Quick_Nick]

From pictures, it looks like there is damage to the fuselage/cabin, inboard and outboard areas of the wing (all the way to the winglet), the horizontal stabilizer (possibly vertical as well), and obviously the engine.

 

[ADSWNJ]

Reports (from airliners.net and pprune.org) suggesting that the cowl ruptured possibly due to fatigue / possibly bleed air overheat. The main fan disc is still intact in the photos, so it's not an engine explosion. But the impact force was sufficient to cut the fuselage directly alongside the cowl position, and to cut the wing fence as well, so there was some major explosive force in the disassembly.

Listening to the LiveATC was cool ... the pilots were hugely professional (apart from leaving a hot mic for a small period), as were ATC and the ground rescue services. Good ending for all, and an interesting case for NTSB.

 

[Andy44]

I have always had a reservation about sitting in the rotation plane of spinning machinery, especially propellers and engine fans. Not that it keeps me from sitting there, but I think about it, and those photos are the reason why.

Back in the 80s I remember a report of a turboprop that threw a propeller which wound up embedded in the cabin. I don't think anyone got hurt but if not they were lucky.

Spinning machinery on the loose is no joke.

 

[Notebook]

Yes, the one I remember is the Sioux City incident.

https://en.wikipedia.org/wiki/United_Airlines_Flight_232

The National Transportation Safety 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 stage 1 fan disk that was manufactured by General Electric Aircraft Engines. The uncontained manner in which the engine failed resulted in high-speed metal fragments being hurled from the engine; these fragments penetrated the hydraulic lines of all three independent hydraulic systems on board the aircraft, which rapidly lost their hydraulic fluid.

 

[MaverickSawyer]

Well, I'm pretty sure that engine is going to be scrap afterwards. There was no doubt a number of cowl fragments that got ingested, and that'll cause a lot of FOD in the core section.

 

[Quick_Nick]

I have always had a reservation about sitting in the rotation plane of spinning machinery, especially propellers and engine fans. Not that it keeps me from sitting there, but I think about it, and those photos are the reason why.

Looks like the debris impacted at a larger than normal gap between the windows/seats. Not sure what's there, maybe equipment for the flight attendants (I would say a gap between classes, but Southwest doesn't have a first class).

 

[ADSWNJ]

Looks like the debris impacted at a larger than normal gap between the windows/seats. Not sure what's there, maybe equipment for the flight attendants (I would say a gap between classes, but Southwest doesn't have a first class).

Seat Guru SWA 737-700

I looked at the layout here ... all seats are regular spacing. Seat 7A has no window though, and that appears to be the exact impact point. I would say that the passenger there was very lucky.

 

[Linguofreak]

I have always had a reservation about sitting in the rotation plane of spinning machinery, especially propellers and engine fans. Not that it keeps me from sitting there, but I think about it, and those photos are the reason why.

Back in the 80s I remember a report of a turboprop that threw a propeller which wound up embedded in the cabin. I don't think anyone got hurt but if not they were lucky.

Spinning machinery on the loose is no joke.

But the irony here is that this was structural failure of the nacelle, not an uncontained failure of the spinny bits, which is what you tend to think of as the type of failure that results in cabin penetrations.

 

[Quick_Nick]

Seat Guru SWA 737-700

I looked at the layout here ... all seats are regular spacing. Seat 7A has no window though, and that appears to be the exact impact point. I would say that the passenger there was very lucky.

I want to believe that the passenger in that seat was previously complaining that his 'window seat' had no window. :lol:

 

[Hielor]

I want to believe that the passenger in that seat was previously complaining that his 'window seat' had no window. :lol:

It's Southwest, they do open seating, so whoever was sitting there would've chosen that seat on their own.

Also, the article said there were only 97 passengers onboard? So, not a full flight, it seems...

 

[Thunder Chicken]

So how did debris get thrown into the side of the fuselage if the turbine disks are intact? The only thing that makes sense is the bleed air used for the cowl anti-icing overpressurized it and blew off the cowl, but that normally wouldn't be much more than 40 psi. It would take a fair amount of pressure to slam something against the fuselage fighting a several-hunded knot slipstream.

Are they sure that the cabin was actually breached, or did the bleed air system get compromised (which would lead to loss of cabin pressurization)?

---------- Post added at 07:25 PM ---------- Previous post was at 07:21 PM ----------

Hmm...may have found the missing cowl:

http://www.boredpanda.com/boeing-737-jet-engine-chair-cowling-fallen-furniture/

 

[boogabooga]

So how did debris get thrown into the side of the fuselage if the turbine disks are intact?

How about a piece of debris from the nacel falls onto the spinning fan and gets smacked and flung into the fuselage- baseball & bat style?

Which way does that fan rotate?

 

[Quick_Nick]

How about a piece of debris from the nacel falls onto the spinning fan and gets smacked and flung into the fuselage- baseball & bat style?

Which way does that fan rotate?

Facing the inlet, looks like counter-clockwise. So objects hitting the top of the fan go toward the fuselage. And quite probably, debris gets flung in all directions.

So, just how much kinetic energy can get imparted into just how big of an object without breaking a fan blade?

The damaged winglet is so far away from the engine, but I suppose bee-line flinging of that degree may be similar to the energy of the fuselage impact.