Decompression Event in an airliner

[BmillsSkier]

You've done it now.

Seriously. I fucking hate sharks.

[Art Shirk]

Emergency crew out the window now. Got hit by lightening coming into Ohare from Knoxville. Happened right at my window and scared the hangover right out of me. Off to Frontera.

[DBdude]

oh boy...

[DBdude]

As far as "how many people are in the air, let's just focus on the A380 alone.
208 planes so far delivered to airlines. Lets say 1/2 of those are in the air at any given time (104 planes). 525-853 passenger capacity (lets say there are an average of 675 people per plane).

156x675 = 70,200 people!

My guess is that there are between 700,000 and 1.5 million people in the air at any given time.

this was just on city in the sky, a documentary shown on PBS. I think the number they gave was at any given time there are two million people flying

[From_the_NEK]

Emergency crew out the window now. Got hit by lightening coming into Ohare from Knoxville. Happened right at my window and scared the hangover right out of me. Off to Frontera.

Yikes. Lots of storms on the radar around Chicago.
Glad you made it to the ground in one piece. Although they try to avoid lightening as it is not good for the plane nor for the hearts of passengers, airliners are designed to handle a lightening strike.

[huckbucket]

The 380 is an abomination.

Abomination or not, It's fuggin hudge!! I snapped this shot at Heathrow on Friday. Massive.

[The AD]

Yikes. Lots of storms on the radar around Chicago.
Glad you made it to the ground in one piece. Although they try to avoid lightening as it is not good for the plane nor for the hearts of passengers, airliners are designed to handle a lightening strike.

For the record it's spelled "lightning." Lightening would be losing weight.

[abraham]

For the record it's spelled "lightning." Lightening would be losing weight.

But personal lightening due to lightning isn't good for the plane, crew, or passengers

[iceman]

The 380 is an abomination.

Just curious, why? From a passenger viewpoint they seem okay.

[From_the_NEK]

But personal lightening due to lightning isn't good for the plane, crew, or passengers

I know that it is spelled ""lightning" I was kind of making fun of the spelling Commonlaw used in his post. I guess I should have gone a different direction with it

[powbmps]

Emergency crew out the window now. Got hit by lightening coming into Ohare from Knoxville. Happened right at my window and scared the hangover right out of me. Off to Frontera.

Same thing happened to me a few years back, coming back east from Denver. Circling Chicago, going in and out of some very dark clouds. I was looking out the window and listening to the pilot on one of the channels. He was talking about getting low on fuel and needing to land. I swear the wing lit up and there was a very loud bang. Scared the shit out of me. The pilot said "yeah....uh....we just took a lightning strike....we need to land". Talking to a commercial airline pilot a couple weeks later, and he said it is not that uncommon, and as NEK said, they are designed for it. The lightning can burn little pin holes in the fuselage where it enters and exits, so they need to be inspected carefully when it happens.

Or so I was told.

[Ted Striker]

Talking to a commercial airline pilot a couple weeks later, and he said it is not that uncommon, and as NEK said, they are designed for it. The lightning can burn little pin holes in the fuselage where it enters and exits, so they need to be inspected carefully when it happens.

True, depending on your definition of common. Every pilot has had (or probably will have) one or two over the course of their career, but anyone who's had more than that is either unlucky or doing it wrong.

A few years ago, I got called on a day off to go pick up an airplane that had been struck by lightning and fly it to a heavy maintenance facility. The line mechanic who inspected the airplane marked each pinhole with a sharpie. There were easily over 100.

The cockpit stank like an electrical fire, but everything still worked.

[Ted Striker]

Just curious, why? From a passenger viewpoint they seem okay.

Oh yeah, I'm sure it's a good airplane.

It was more a comment on being stuck in a metal tube with 850 people for a dozen hours. Kinda grosses me out - especially because I know how the thing works. After takeoff, every molecule of air in the cabin comes from the compressor stage of the engines. Getting that compressed air takes work, which means fuel burned for a purpose other than propulsion. So some clever engineers came up with the idea of recirculating some of the air in the cabin to save fuel. Much of that recirculated air has been exhaled (or worse) by your cabinmates. Hopefully, (doubtfully) none of them are sick.

And don't even get me started on the lavatories.

[abraham]

I know that it is spelled ""lightning" I was kind of making fun of the spelling Commonlaw used in his post. I guess I should have gone a different direction with it

I thought that's what we were all doing?

[The SnowShow]

This is the kind of turbulence that freaks the shit out of me: https://youtu.be/NB__Wf06S8M

[huckbucket]

This is the kind of turbulence that freaks the shit out of me: https://youtu.be/NB__Wf06S8M

Just keep reminding yourself that there's a lot of air under your wings between you and the ground and that there would have to be a 5,000 ft vacuum for you to suddenly plummet to earth. Fact check for Pisteoff, but I doubt a plane has ever fallen out of the sky due to turbulence.

[iceman]

Oh yeah, I'm sure it's a good airplane.

It was more a comment on being stuck in a metal tube with 850 people for a dozen hours. Kinda grosses me out - especially because I know how the thing works. After takeoff, every molecule of air in the cabin comes from the compressor stage of the engines. Getting that compressed air takes work, which means fuel burned for a purpose other than propulsion. So some clever engineers came up with the idea of recirculating some of the air in the cabin to save fuel. Much of that recirculated air has been exhaled (or worse) by your cabinmates. Hopefully, (doubtfully) none of them are sick.

And don't even get me started on the lavatories.

I should have replied when you posted this, I read it then, but it thoroughly bummed me out so I moved on. But thanks for writing it, and I guess it's obvious the cockpit gets the same air as everyone else (or is it?), that seems like a lot to deal with at work.

[Ted Striker]

Technically, we do have a non-recirculated air source in the cockpit, but all the air goes everywhere. We can smell the coffee brewing in the forward galley after takeoff.

Twin engine airplanes have two independent air conditioning systems for redundancy, and it's typical for manufacturers to bias one toward the cockpit and the other toward the rear cabin, but that's really more for temperature control (fewer bodies in the front) than air quality.

The good news is that Boeing is all over this now. One of the design goals on the 787 was to improve air quality without burning more fuel. The air conditioning system is electrically powered vs pneumatic which is typical on older airliners, so the air is more humid. Additionally, the cabin is capable of a higher than typical pressure differential, so more O2 in your blood.

[Ted Striker]

I doubt a plane has ever fallen out of the sky due to turbulence.

Not that I'm aware of, and it wouldn't be that type of turbulence.

In order to bend the airframe, the bumps would have to be severe enough that strapped into your seat you would be flopping around like the balloon man thing at a car dealer, and anything not strapped down would be thrown around the cabin. Even then, bent airplanes still get to the airport.

[huckbucket]

Even then, bent airplanes still get to the airport.

I always thought aluminum breaks catastrophically rather than bends.

[Ted Striker]

It bends up to a point. That point may be sooner than other materials, but airframes can (and have) be (been) bent and remain intact. An example closer to home would be lots of riders (myself included) have bent aluminum bike frames without cracking them, but at some point they do crack/fail.

Plus, the enginerds choose their alloys carefully.

There have been airframe breakups, but not due to typical clear air turbulence (AFAIK)

[DJSapp]

I always thought aluminum breaks catastrophically rather than bends.

[Timberridge]

Oh yeah, I'm sure it's a good airplane.

It was more a comment on being stuck in a metal tube with 850 people for a dozen hours. Kinda grosses me out - especially because I know how the thing works. After takeoff, every molecule of air in the cabin comes from the compressor stage of the engines. Getting that compressed air takes work, which means fuel burned for a purpose other than propulsion. So some clever engineers came up with the idea of recirculating some of the air in the cabin to save fuel. Much of that recirculated air has been exhaled (or worse) by your cabinmates. Hopefully, (doubtfully) none of them are sick.

And don't even get me started on the lavatories.

In these respects, plus never having to worry about a decompression event the DC3 is a far superior airplane.

[huckbucket]

Flex, bend and break. Three different concepts?

[DJSapp]

Flex, bend and break. Three different concepts?

One concept.





Yield Strength--how much it can take before being permanently deformed (aka elastic deformation)
Ultimate Strength--how much it can take before catastrophically failing, though it will be permanently deformed through strain hardening (aka plastic deformation)
Fracture--aka it dun broke in two pieces

Aluminum has a lower difference between strength and ultimate strength WRT steel and high carbon steel.