Southwest Airlines Flight 1380 Engine Failure

[Speed 3]

Fast and Spurious said:

Jamesgt said:

Why does a fan blade need cooling?

It would melt. It's operating in temperatures higher than its melting point so cooling is essential.

Turbine blades opereate in temperatures higher than their melting point so they have air passage cooling but fan blades most definitely don't. That's why its called the cold section of the engine. They are solid - generally titaninium or Ti alloy and these days composite.

[anonymous-user]

Speed 3 said:

Fast and Spurious said:

Jamesgt said:

Why does a fan blade need cooling?

It would melt. It's operating in temperatures higher than its melting point so cooling is essential.

Turbine blades opereate in temperatures higher than their melting point so they have air passage cooling but fan blades most definitely don't. That's why its called the cold section of the engine. They are solid - generally titaninium or Ti alloy and these days composite.

I think the confusion is because all these blades kind of look like fans, people call all the different stage blades fan blades but obviously the fan is just the bit on the front.

There aren’t really turbine fan blades or compressor fan blades in a jet engine, just turbine blades and compressor blades.

The only fan blades are on the fan itself at the front.

[Speed 3]

El stovey said:

I think the confusion is because all these blades kind of look like fans, people call all the different stage blades fan blades but obviously the fan is just the bit on the front.

There aren’t really turbine fan blades or compressor fan blades in a jet engine, just turbine blades and compressor blades.

The only fan blades are on the fan itself at the front.

Sorry to repeat your earlier more illustrative explanation- browser took me to “Last visit” which skipped ones I hadn’t actually seen

[Mave]

Jamesgt said:

Krikkit said:

Most of them are actually relatively light, being posh titanium/aluminium alloys. A fan blade, for example, is usually a hollow structure to allow cooling air to be passed through.

That said, the parts which rotate have a huge amount of energy imparted.

Why does a fan blade need cooling?

It doesn't. The hollow structure in a fan blade is primarily to save weight - nothing to do with cooling.

[MB140]

I was also surprised by the wishy washy nature of the comms, every year on my tac check and indeed during my training flights I was required to demonstrate sending a Mayday and Pan.

Civilian world uses this Acronym I believe or as far as I was taught.

TNIPPLH (which I remember as T nipple H)

T = type =747 for example
N = nature = fire onboard
I = Intentions = descending to FL200
P = people = 150 people on board
P = position = lat/long or bearing and range
L= level = FL320
H = Heading

Which would be said something like this

Mayday mayday mayday
This is speedbird1, speedbird1, speedbird1
Boeing747
Fire onboard
Defending Flight level 200
150 soles onboard
Nxxxxxxxxx, Exxxxxxxxxx
Flight level 320
Heading 090 degrees.
Spedbird1
Mayday

In the military we use a different but similar format and I use the following saying to remember it

Please to have sexy Amy tickle testicles at every ickle chance.

Needless to say I’m not going to write it all out but it conveys similar information.

Certainly during this flight recording I never heard anything that sounded like a structured mayday Tx.

Edited by MB140 on Tuesday 24th April 12:02

[NDT]

Mave said:

It doesn't. The hollow structure in a fan blade is primarily to save weight - nothing to do with cooling.

The fan blades on a CFM56 are forged titanium. There's no hollow part.

[djc206]

MB140 said:

I was also surprised by the wishy washy nature of the comms, every year on my tac check and indeed during my training flights I was required to demonstrate sending a Mayday and Pan.

Civilian world uses this Acronym I believe or as far as I was taught.

TNIPPLH (which I remember as T nipple H)

T = type =747 for example
N = nature = fire onboard
I = Intentions = descending to FL200
P = people = 150 people on board
P = position = lat/long or bearing and range
L= level = FL320
H = Heading

Which would be said something like this

Mayday mayday mayday
This is speedbird1, speedbird1, speedbird1
Boeing747
Fire onboard
Defending Flight level 200
150 soles onboard
Nxxxxxxxxx, Exxxxxxxxxx
Flight level 320
Heading 090 degrees.
Spedbird1
Mayday

In the military we use a different but similar format and I use the following saying to remember it

Please to have sexy Amy tickle testicles at every ickle chance.

Needless to say I’m not going to write it all out but it conveys similar information.

Certainly during this flight recording I never heard anything that sounded like a structured mayday Tx.

Edited by MB140 on Tuesday 24th April 12:02

No need for type, current level, heading unless deviating from previous track or position if operating inside controlled airspace as controllers know all that. All I need is Mayday, callsign (once is enough), nature of emergency and if known intentions. Souls on board is something that can be established later. In all honesty all I need immediately is a 7700 squawk as that highlights the aircraft on radar and means I can start shifting everyone else out of the way, 7700 burns through our radar height filters so every controller in the vicinity sees it and can start planning ahead, splitting sectors, QSY other traffic (getting it off your frequency/s for those not familiar) etc etc.

I’d expect “Mayday, mayday, mayday, Southwest 1380, engine failure and decompression, descending flight level 100”. As you say the Americans seem to be a bit more verbose.

[MB140]

djc206 said:

MB140 said:

I was also surprised by the wishy washy nature of the comms, every year on my tac check and indeed during my training flights I was required to demonstrate sending a Mayday and Pan.

Civilian world uses this Acronym I believe or as far as I was taught.

TNIPPLH (which I remember as T nipple H)

T = type =747 for example
N = nature = fire onboard
I = Intentions = descending to FL200
P = people = 150 people on board
P = position = lat/long or bearing and range
L= level = FL320
H = Heading

Which would be said something like this

Mayday mayday mayday
This is speedbird1, speedbird1, speedbird1
Boeing747
Fire onboard
Defending Flight level 200
150 soles onboard
Nxxxxxxxxx, Exxxxxxxxxx
Flight level 320
Heading 090 degrees.
Spedbird1
Mayday

In the military we use a different but similar format and I use the following saying to remember it

Please to have sexy Amy tickle testicles at every ickle chance.

Needless to say I’m not going to write it all out but it conveys similar information.

Certainly during this flight recording I never heard anything that sounded like a structured mayday Tx.

Edited by MB140 on Tuesday 24th April 12:02

No need for type, current level, heading unless deviating from previous track or position if operating inside controlled airspace as controllers know all that. All I need is Mayday, callsign (once is enough), nature of emergency and if known intentions. Souls on board is something that can be established later. In all honesty all I need immediately is a 7700 squawk as that highlights the aircraft on radar and means I can start shifting everyone else out of the way, 7700 burns through our radar height filters so every controller in the vicinity sees it and can start planning ahead, splitting sectors, QSY other traffic (getting it off your frequency/s for those not familiar) etc etc.

I’d expect “Mayday, mayday, mayday, Southwest 1380, engine failure and decompression, descending flight level 100”. As you say the Americans seem to be a bit more verbose.

Yep I remember when going through training this was taught as a perfect example (what I typed originally) all my instructors have since said it’s a tac check we need the correct answers but in reality so long as you get most of the info out in some sort of order it’s enough. I often questioned the position, flight level, heading stuff as so long as your on radar it’s already known but it was pointed out to me that in some parts of the world there is no radar so it is helpful if you get all the info out.

I appreciate if your in a radar controlled area it’s overkill giving FL, heading, speed etc. But it’s a good habit to get into for that occasion when you need to declare a pan/mayday and your not on radar and the controllers don’t actually know where you are.

Hell some places don’t even have primary radar so squarking 7700 for a secondary radar return is pointless. But I do accept that in most developed countries control areas 7700 gives you pretty much everything you need apart from nature of emergency and intentions. I’m not a pilot but I would imagine the soles on board is filed as part of the flight plan. I certainly know it’s relayed to atc as part of the startup clearance.

[Mave]

NDT said:

Mave said:

It doesn't. The hollow structure in a fan blade is primarily to save weight - nothing to do with cooling.

The fan blades on a CFM56 are forged titanium. There's no hollow part.

I didn't know that. Honeycomb and diffusion bonded titanium fan blades have been around for decades - I assumed they would be used on a wide chord, snubberless fan like the CFM!

[Zad]

I think you mean turbine blade? The fan blades are at the front and provide the bulk of the thrust, and take the brunt of the hits from foreign objects flying around.

[Mave]

Zad said:

I think you mean turbine blade? The fan blades are at the front and provide the bulk of the thrust, and take the brunt of the hits from foreign objects flying around.

No, I'm talking about the fan blades :-) - the discussion was about the amount of damage the liberated blade from the front of the engine could do, and whether it was hollow or solid titanium.

Edited by Mave on Tuesday 24th April 21:46