Southwest Airlines Flight 1380 Engine Failure
Discussion
Max_Torque said:
Is one engine enough on a 737 to maintain full cabin pressurization?
Yes, single pack operation is something that is tested. The engine bleed and A/C system goes into a 'high flow' mode on the remaining engine. However the procedure is generally still to descend quickly to 10'000ft.
With a window out, there's no way the aircraft will hole pressure no matter what is being pumped in.
Chuck328 said:
It appears only one fan blade detached? With the low pressure at the front (intake) of the engine, how freakish for that one blade to hit the window! Or am I missing something?
Wasn't necessarily the blade that hit the window, a lot of fan case and nacelle came off too. The unfortunate woman was likely killed by the secondary phase of debris if she got partially sucked out after the initial strike had taken out the window. Anything coming off a disintegrating engine is more than likely to hit the fuselage or empennage somewhere. Just slightly unusual for it to take out a single window. Look at the damage caused when fan cowls depart on A320's. For those that don't know, there is a row ahead of the emergency exit that has a blank window.
This is to mitigate an uncontained engine failure, but assumes it's travelling laterally, exactly perpendicular to the engine. I don't know of any cases where this has actually had any benefit on a turbofan powered aircraft. It generally dates as a design philosophy from propliners where a prop is likely to travel in that direction if it lets go.
I once did a flight testing course at Cranfield in a Jetstream and on takeoff we had a couple of loud thumps. Upon landing we discovered a bent prop which had been caused by the engine sucking up bits of concrete from a deteriorated runway and flinging them at the fuselage.....
kapiteinlangzaam said:
The recent training we had is that more and more airlines are now disregarding the FL100 'rule' which really surprised me.
Turkish airlines for eg. drop initially to 18000ft. And start working on the problem from there.
Most people can breath ok above 10,000 ft though. I think 18,000 might be difficult for some? Turkey has a lot of high ground and any eastbound flights from turkey will be flying for long periods with terrain above 10,000. Turkish airlines for eg. drop initially to 18000ft. And start working on the problem from there.
In Europe and Central Asia having to avoid Syria, Iraq and the northern part of the Black Sea around the Crimea has a lot more airways with high minimum safe altitudes on them around turkey, Azerbaijan, Turkmenistan, Afghanistan etc
They’d still be aiming to get the aircraft down to 10,000 Ft soon though. Many aircraft types only have around 12 mins of cabin oxygen through the masks.
For anyone interested, in a decompression, the pilots will be doing this sort of thing.
General cabin pressurisation is controlled by regulating the flow of air, either bleed air from engines or electrically with air compressors and outflow valves on the fuselage.
Normally the cabin altitude is controlled to be around 8,000ft in some newer aircraft it’s lower at around 6000ft. You’ll get some kind of warning in the cockpit when the cabin altitude rises to around 10,000.
So you then (depending on aircraft and airline)
-Put on your oxygen masks (these are stowed beside the pilots and you have a bit of a faf with headsets and glasses etc doing it)
-Getting communication established between the pilots (some button pressing to select microphones in the mask rather than headset.
-Checking what’s happening
There may be an initial call to cabin crew and air traffic depending on the airline and allocation of duties.
Then if you need to go down, you have to select a lower altitude do some more selections with the autopilot and thrust levers (as fitted) and speed brakes depending on what caused the decompression. Plus if there’s other aircraft below you, you have to do some turning before actually descending.
Once you’re on your way down you need to be making sure the altitude you’ve chosen to go to is safe, and you’ve done the above correctly, checking passenger oxygen is working, turn on lights to show other aircraft where you are, set 7700 on the transponder to tell air traffic control what’s up. Possibly sending an emergency message report by datalink.
Then because you’ve likely increased the speed to descend quicker you have to slowdown a bit before you level off to stop the aircraft overspeeeding.
Then there’s communications with atc, cabin crew ,passengers etc.
Having an engine explode before all that obviously adds to your workload as you’d have done initial actions to deal with that and then when the hole appeared, stop to do the descent and then complete the engine problem checklists etc after levelling off.
Maybe they happen simultaneously and your displays fill up with messages about cabin alt and engine problems. You’ve got to prioritise and get your oxygen masks on first as you can’t do the engine drills very well if you’ve got hypoxia or are unconscious.
Edited by anonymous-user on Thursday 19th April 11:18
El stovey said:
.......... You’ve got to prioritise and get your oxygen masks on first as you can’t do the engine drills very well if you’ve got hypoxia or are unconscious.
Remember seeing an interview with a passenger after a decompression event.Complained bitterly about the selfishness of the cabin crew putting on their mobile oxgen kit before helping the passengers.
Steve
Max_Torque said:
Is one engine enough on a 737 to maintain full cabin pressurization?
Witness reports are of a bang, the oxygen masks dropping, about 10 sec, then the window blowing out. Seems too quick to have a loss of cabin pressure just by loosing the fan off the front of one engine no? (ie before the gross window failure lead to depressurization) Might be the eye witness account just got the order wrong?
Assuming the passenger's recollection is correct I'd imagine the sequence was something like:Witness reports are of a bang, the oxygen masks dropping, about 10 sec, then the window blowing out. Seems too quick to have a loss of cabin pressure just by loosing the fan off the front of one engine no? (ie before the gross window failure lead to depressurization) Might be the eye witness account just got the order wrong?
- Fan blade departs
- Pressure loss at the bleed circuit for the dead engine causes masks drop automatically
- Front cowling breaks up due to damage from the blade, some debris (or the blade itself) punctures the partially-broken window
- Pressure differential pops the window completely, and sucks the poor victim out
Ayahuasca said:
RobDickinson said:
Ayahuasca said:
I don't think anyone died of asphyxia - the masks worked.
Because the skilled pilots dropped altitude quickly... AshVX220 said:
Which is lucky, because they certainly weren't used as intended.
How do you know that the photo wasn't taken at a lower altitude and the masks were no longer needed so people popped them off their noses? I cant see anyone taking a selfie during the point when the aircraft is in a dive.RobDickinson said:
Picture and story of the masks is front page on stuff, one of nz's big news sites.
Imo could be helped by shaping the mask so it's actually obvious
They are designed without it intentionally. The idea is so that there is no proper mask orientation required ie. there is no upside down. Also this shape more easily fits many different sized and shaped faces: children, adults, big nose, small nose, narrow face, wide face, etc.Imo could be helped by shaping the mask so it's actually obvious
As long as enough oxygen reaches the lungs, it doesn't matter whether it is breathed through the nose of the mouth or both.
I suspect the idea of having the nose in the mask is to allow nose breathing, but I suspect a) most panicked people breathe through the mouth, and b) if you wanted to breathe through the nose you would instinctively put the mask over your nose. It would be better in theory - but maybe difficult in a live situation - to breathe through the nose as that would help to prevent hyperventilation (so would exhaling into the mask), and allow the limited supply of oxygen to last longer.
I suspect the idea of having the nose in the mask is to allow nose breathing, but I suspect a) most panicked people breathe through the mouth, and b) if you wanted to breathe through the nose you would instinctively put the mask over your nose. It would be better in theory - but maybe difficult in a live situation - to breathe through the nose as that would help to prevent hyperventilation (so would exhaling into the mask), and allow the limited supply of oxygen to last longer.
KrazyIvan said:
Training/procedure and real life are not the same, but if you don't think anything they did was note worthy, then fair enough, me personally I still think they deserve a virtual pat and recognition on the back for job well done in a difficult situation.
It’s a sight to behold. I used to work herc’s (C130-J) and was lucky/unlucky enough to be in the cockpit when we had an engine fire warning. (Transpired later to be FireWire damaged due to vibration giving a false alarm). It was the first (and only to this date) time I had seen an inflight emergency from inside the cockpit. Jesus Christ are they good, talk about calm, professional and so so so quick with h their drills (engine fire is a red card drill (life threatening), they never even looked at th FRCs, it was just pure instinct.
I realise as miltry pilots they spend so much time in a simulator and have access to training civilian pilots probably don’t get but it made me realise 2 things. I could never be a pilot and boy do they earn their money when it goes wrong.
Ayahuasca said:
RobDickinson said:
Ayahuasca said:
I don't think anyone died of asphyxia - the masks worked.
Because the skilled pilots dropped altitude quickly... Speed 3 said:
For those that don't know, there is a row ahead of the emergency exit that has a blank window.
This is to mitigate an uncontained engine failure, but assumes it's travelling laterally, exactly perpendicular to the engine. I don't know of any cases where this has actually had any benefit on a turbofan powered aircraft. It generally dates as a design philosophy from propliners where a prop is likely to travel in that direction if it lets go.
I get the principle, but surely a detached anything would penetrate aluminium as easily (if not more so) as it would do a window? Or is the idea to stop a window unit being blown out?This is to mitigate an uncontained engine failure, but assumes it's travelling laterally, exactly perpendicular to the engine. I don't know of any cases where this has actually had any benefit on a turbofan powered aircraft. It generally dates as a design philosophy from propliners where a prop is likely to travel in that direction if it lets go.
MB140 said:
KrazyIvan said:
Training/procedure and real life are not the same, but if you don't think anything they did was note worthy, then fair enough, me personally I still think they deserve a virtual pat and recognition on the back for job well done in a difficult situation.
It’s a sight to behold. I used to work herc’s (C130-J) and was lucky/unlucky enough to be in the cockpit when we had an engine fire warning. (Transpired later to be FireWire damaged due to vibration giving a false alarm). It was the first (and only to this date) time I had seen an inflight emergency from inside the cockpit. Jesus Christ are they good, talk about calm, professional and so so so quick with h their drills (engine fire is a red card drill (life threatening), they never even looked at th FRCs, it was just pure instinct.
I realise as miltry pilots they spend so much time in a simulator and have access to training civilian pilots probably don’t get but it made me realise 2 things. I could never be a pilot and boy do they earn their money when it goes wrong.
Talking to other friends who are pilots and have been in similar circumstances, anything in anything from a light aircraft to a full on airliner, it seems the training kicks in and you don't have time to panic.
tannhauser said:
I get the principle, but surely a detached anything would penetrate aluminium as easily (if not more so) as it would do a window? Or is the idea to stop a window unit being blown out?
Like I said, it's a somewhat outdated design principle orginated from props which have a bit more blunt, low pressure force but you are right in that a small puncture (even at high energy/velocity) is preferable to a whole window blowing. The area is typically thicker aluminium alloy than the general fuselage on some aircraft, being a "belt" principle.Gassing Station | Boats, Planes & Trains | Top of Page | What's New | My Stuff