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(Yahoo)   Bagram crash recorded on dashcam--oh, my. A big airplane like that shouldn't just stop in mid-air   (news.yahoo.com) divider line 537
    More: Scary, Bagram, Bagram Airfield, public-benefit corporation, evidence  
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33870 clicks; posted to Main » on 30 Apr 2013 at 9:26 PM (1 year ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2013-05-01 12:29:35 AM

DeadPuppySociety: Quantum Apostrophe: scubamage: at least they got to go out doing something they loved

So did you know who.

Michael Hutchence?


I was thinking Dale Earnhardt.
 
2013-05-01 12:30:53 AM
Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.

Put me down for human error (only because it usually is), or control system malfunction.
 
2013-05-01 12:31:57 AM

sjcousins: JohnAnnArbor: I_Am_Weasel: SpikeStrip: remus: SpikeStrip: remus: SpikeStrip: remus: this isn't going to be pretty.

opposed to what?

// have actually had a conversation, while eating lunch, that included the words "what's that?  I think it's a piece of tongue..."
// continued eating lunch...

what happened next?

We dug it out and sent it to the lab.  What else do you do with some tongue?  We don't normally get the parts, so it was a little exciting.

no, what happened after you continued eating lunch, what with the ellipsis and all

You had an ellipsis for lunch?

It's the thing, lately.  I had a couple quote marks and a tilde, myself.

You're lucky. I had a bowl of parentheses that were full of ampersands. I had a semi colon after that.



Ampersands are the worst thing for any VaJayJay. Makes ya biitchy!
 
2013-05-01 12:33:33 AM

thedumbone: Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.

Put me down for human error (only because it usually is), or control system malfunction.


You've got 20,000 pounds of thrust counteracting that, at least for a little bit.  It only impacted nose first once it got the 10 milliseconds of control back, at which point I'm sure all that cargo shifted to the front.
 
2013-05-01 12:34:17 AM

Peki: iron_city_ap: Not CSB: Apparently, my first officer used to work with and knew one of the guys onboard.

It just makes you feel ill seeing something like this.

Tell him someone sends a hug from California. My bro works on an aircraft carrier in the gulf; all military is family.

Valiente: RexTalionis: Damn, that is a really bad stall.

Classic execution. I've seen Pittmans do that at air shows at much greater heights, but not a big honking jet.

It's like they took off, pulled all throttles to zero, and yanked the yoke into their ball sacks, standing the plane on its tale.

A whole lot of ugly.

Makes for a great story though.


You win an Internet. Me making a typo like that is pretty rare. I blame the skipper's nerve tonic, personally.
 
2013-05-01 12:36:59 AM

thedumbone: Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.


Inertia.
 
2013-05-01 12:38:17 AM

Lsherm: You've got 20,000 pounds of thrust counteracting that


More like 100,000.
 
2013-05-01 12:38:28 AM

remus: SpikeStrip: remus: this isn't going to be pretty.

opposed to what?

I worked one where the pilot ejected and only got a few scratches on his arm from the sage brush while he was walking out to the nearest road.

I worked another where the co-pilot was beheaded by a bird coming thru the canopy.

The worst, hands down, was the A-10 Lt Col who ejected in a full bank horizontal to the ground; his seat worked perfectly right until it hit the Oak tree.  It was worse than the decapitated guy because the lab reeked for weeks.

// have actually had a conversation, while eating lunch, that included the words "what's that?  I think it's a piece of tongue..."
// continued eating lunch...


I am so going to hell. I laughed way too hard at the A-10 bit.

/Still laughing
//Aisle seat
 
2013-05-01 12:40:45 AM
http://www.youtube.com/watch?v=wXJ_MfAnjgQ

This video has a graphic of how load shift works, for anyone who wants to take a look.  It's not the best graphic, but it gives a basic idea of how it happens.
 
2013-05-01 12:41:31 AM
Charlie Freak:
cyberspacedout:
powhound:
ElLoco:


OK, I understand now that you can't do anything against roll in a stall even at full power. Thank you for the answers.
 
2013-05-01 12:42:09 AM

HBK: WizardofToast: One of my greatest fears is riding a plane that just drops out of the sky mid-flight. Now I'm going to hate every take off unless all the fat people are kept in the center seats.

/I know fat people can't bring down a plane
//But ya never know

Here's a story for you, and something that maybe the pilot-folk here on fark can shed some light on.

I was sleeping on a Continental flight from Little Rock to Houston. I woke up and my stomach was in my chest, like when you're on one of those tower of terror or dungeon drop rides at an amusement park. The plane felt like it was just dropping out of the sky. Everyone started cursing and screaming.

It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out.  Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."

I muttered to myself "That's how Goose died." and the guy next asked me frantically "Who's Goose? is that a friend of yours?" He hadn't seen the movie.
 So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?


Your pilot just dodged a plane by less than 100 yds.
 
2013-05-01 12:44:06 AM

Quantum Apostrophe: Lsherm: You've got 20,000 pounds of thrust counteracting that

More like 100,000.


More like 240,000+.
 
2013-05-01 12:44:44 AM

Peki: Strangerarranger: Well I hope those in First Class got marshmellows on sticks before they landed. I'm thinking they would have had a good use for those. S'Mores anyone?

And I hope nobody had to pay to check their baggage on the flight. I'm thinkig all baggage was lost inflight.

I think you missed the part where it's a cargo plane.



Technically, the cargo was lost on the ground. It's *c-o-n-t-r-o-l* that was lost in-flight.
 
2013-05-01 12:45:03 AM

Quantum Apostrophe: Lsherm: You've got 20,000 pounds of thrust counteracting that

More like 100,000.


OK, fark, I didn't look it up, OK?  But it's pretty clear from the video what happened.
 
2013-05-01 12:45:55 AM

base935: Quantum Apostrophe: Lsherm: You've got 20,000 pounds of thrust counteracting that

More like 100,000.

More like 240,000+.


Yup, not mathing too well tonight.
 
2013-05-01 12:46:01 AM

youmightberight: HBK: WizardofToast: One of my greatest fears is riding a plane that just drops out of the sky mid-flight. Now I'm going to hate every take off unless all the fat people are kept in the center seats.

/I know fat people can't bring down a plane
//But ya never know

Here's a story for you, and something that maybe the pilot-folk here on fark can shed some light on.

I was sleeping on a Continental flight from Little Rock to Houston. I woke up and my stomach was in my chest, like when you're on one of those tower of terror or dungeon drop rides at an amusement park. The plane felt like it was just dropping out of the sky. Everyone started cursing and screaming.

It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out.  Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."

I muttered to myself "That's how Goose died." and the guy next asked me frantically "Who's Goose? is that a friend of yours?" He hadn't seen the movie.
 So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?

Your pilot just dodged a plane by less than 100 yds.


This. Although wake turbulence (not exactly "jetwash") can severely disturb flight.
 
2013-05-01 12:46:33 AM

thedumbone: Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.

Put me down for human error (only because it usually is), or control system malfunction.


Dude. The control system worked.  The load shifted suddenly making it tail heavy, so it was a stall-spin to the left due to too high angle of attack.  Lowering the nose is how you recover from a stall.  They correctly leveled the wings with opposite aileron and lowered the nose with the elevator.  They needed another few thousand feet of altitude to recover successfully.
 
2013-05-01 12:48:15 AM

SpikeStrip: people_are_chumps: I'm flying for the first time in 12 years next week so I'm not getting a kick....

we're all missing the point here, which is to give people_are_chumpsencouragement.

[i780.photobucket.com image 220x230]



OH, now I see........ Ok, well....... uhhhhhhhhhhhh........ Ok, got it: PRC, don't worry, no matter what happens to the plane, most likely you'll come out ALIVE.

/How does that one bite ya??? Right on the a55, huh?
/And watch out for clouds; some of them have rocks in 'em.
 
HBK
2013-05-01 12:48:56 AM

Charlie Freak: youmightberight: HBK: WizardofToast: One of my greatest fears is riding a plane that just drops out of the sky mid-flight. Now I'm going to hate every take off unless all the fat people are kept in the center seats.

/I know fat people can't bring down a plane
//But ya never know

Here's a story for you, and something that maybe the pilot-folk here on fark can shed some light on.

I was sleeping on a Continental flight from Little Rock to Houston. I woke up and my stomach was in my chest, like when you're on one of those tower of terror or dungeon drop rides at an amusement park. The plane felt like it was just dropping out of the sky. Everyone started cursing and screaming.

It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out.  Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."

I muttered to myself "That's how Goose died." and the guy next asked me frantically "Who's Goose? is that a friend of yours?" He hadn't seen the movie.
 So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?

Your pilot just dodged a plane by less than 100 yds.

This. Although wake turbulence (not exactly "jetwash") can severely disturb flight.


Well that's terrifying. Doesn't GPS/radar, whatever give you a good heads up about nearby planes? Did the pilot just fall asleep or something?
 
2013-05-01 12:50:03 AM

Lsherm: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Put me down for human error (only because it usually is), or control system malfunction.

You've got 20,000 pounds of thrust counteracting that, at least for a little bit.  It only impacted nose first once it got the 10 milliseconds of control back, at which point I'm sure all that cargo shifted to the front.


Thrust doesn't work that way.  Aircraft are design to minimize pitch changes due to thrust, with the exception of certain seaplanes.

Also, you don't get "control back" until you get speed back, and that doesn't happen until the nose drops.

FizixJunkee: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Inertia.


Inertia doesn't cause a aircraft to change from nose-up to nose-down - it tends to keep things where they are.
 
2013-05-01 12:51:32 AM

thedumbone: Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.

Put me down for human error (only because it usually is), or control system malfunction.


The tailplane's natural state is to fly upside down - in normal flight it is actually producing lift that causes a tail-down moment. When the main wing stalls, the tail often stalls as well, either due to the same low speed or because it is in the buffeted slipstream from the wing. The loss of this tail-down moment causes, you guessed it, a nose-down moment. Lower altitude, less time, and the tail-first thing might have played out, but there are a lot of other dynamics at play here as the wings and horizontal stabs alternately tried to go flying again.
 
2013-05-01 12:52:49 AM

netringer: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Dude. The control system worked.  The load shifted suddenly making it tail heavy, so it was a stall-spin to the left due to too high angle of attack.  Lowering the nose is how you recover from a stall.  They correctly leveled the wings with opposite aileron and lowered the nose with the elevator.  They needed another few thousand feet of altitude to recover successfully.


If they could have levelled the nose with the elevator, they would have done it before they stalled.  It is a textbook example of how you attempt to recover from a stall - in a normally balanced airplane.

Also, you level the wings with opposite rudder, not aileron, due to adverse yaw.
 
2013-05-01 12:54:54 AM

Charlie Freak: Wow, that's got to be a cargo shift.


Either that or massively bad weight and balance during the load process (if it hasn't been said already in the comments, sorry I haven't read them all).

But yeah, highly suspect the cargo went waay off the CG to the aft. Looks like flaps and gear were full as well so that thing went to the extreme AoA.
 
2013-05-01 12:56:50 AM

flightmonkey88: Here is another unsettling bit, That bird went down on the edge of an old russian minefield at the end of the runway


...sigh. Such a tragedy.
 
2013-05-01 12:57:05 AM

HBK: Charlie Freak: youmightberight: HBK: WizardofToast: One of my greatest fears is riding a plane that just drops out of the sky mid-flight. Now I'm going to hate every take off unless all the fat people are kept in the center seats.

/I know fat people can't bring down a plane
//But ya never know

Here's a story for you, and something that maybe the pilot-folk here on fark can shed some light on.

I was sleeping on a Continental flight from Little Rock to Houston. I woke up and my stomach was in my chest, like when you're on one of those tower of terror or dungeon drop rides at an amusement park. The plane felt like it was just dropping out of the sky. Everyone started cursing and screaming.

It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out.  Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."

I muttered to myself "That's how Goose died." and the guy next asked me frantically "Who's Goose? is that a friend of yours?" He hadn't seen the movie.
 So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?

Your pilot just dodged a plane by less than 100 yds.

This. Although wake turbulence (not exactly "jetwash") can severely disturb flight.

Well that's terrifying. Doesn't GPS/radar, whatever give you a good heads up about nearby planes? Did the pilot just fall asleep or something?


Normally. GPS no. ATC radar with Mode C transponders, TCAS, and ADS-B yes, but only if everyone is equipped, participating, and paying attention. Your case could have very well been the result of a TCAS resolution advisory (RA) in which the TCAS of both conflicting aircraft have "talked" to each other and advised the pilots of each how to deconflict. This usually involves putting on some climb or descent right the fark now and telling ATC about it afterwards.

It also means a lot of paperwork for a few people.
 
2013-05-01 12:57:05 AM

HBK:  So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?


It has nothing to do with the engines.

It's called wake turbulence:

www.faa.gov www.pilotfriend.com
graphics8.nytimes.com

The air gets stirred up in vortexes - little tornadoes - from the tips of the wings of a preceding jet.  The vortexes can last for a long time in still air. They descend below the previous jet's flight path and and spread out horizontally.

They can flip a smaller plane on its back, and they're invisible.  Planes have to try to fly above the flight path of the previous.

Maverick and Goose had an engine flameout when they got so close to the previous jet's exhaust one of their F-14's engine intake starved for clean air and the engine quit.
 
2013-05-01 12:58:53 AM

thedumbone: netringer: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Dude. The control system worked.  The load shifted suddenly making it tail heavy, so it was a stall-spin to the left due to too high angle of attack.  Lowering the nose is how you recover from a stall.  They correctly leveled the wings with opposite aileron and lowered the nose with the elevator.  They needed another few thousand feet of altitude to recover successfully.

If they could have levelled the nose with the elevator, they would have done it before they stalled.  It is a textbook example of how you attempt to recover from a stall - in a normally balanced airplane.

Also, you level the wings with opposite rudder, not aileron, due to adverse yaw.


Yeah. That.  Brain fart.
 
2013-05-01 12:59:50 AM

Charlie Freak: thedumbone: Put me down as the (first?) to say - NOT a load shift.

The tailplane's natural state is to fly upside down - in normal flight it is actually producing lift that causes a tail-down moment. When the main wing stalls, the tail often stalls as well, either due to the same low speed or because it is in the buffeted slipstream from the wing. The loss of this tail-down moment causes, you guessed it, a nose-down moment. Lower altitude, less time, and the tail-first thing might have played out, but there are a lot of other dynamics at play here as the wings and horizontal stabs alternately tried to go flying again.


The tail is designed to stall after the wing.  A tail stall is a whole different beast and rarely happens outside of icing conditions.

In any event, a stalled tail is producing effectively zero lift.  A flying tail, with the elevator forward, is trying to push the nose down.  A stalled tail would be LESS likely to drop the nose than a flying one.

/CFII, AMEL ASEL, 2000 hrs
 
2013-05-01 12:59:53 AM

HBK: WizardofToast: One of my greatest fears is riding a plane that just drops out of the sky mid-flight. Now I'm going to hate every take off unless all the fat people are kept in the center seats.

/I know fat people can't bring down a plane
//But ya never know

Here's a story for you, and something that maybe the pilot-folk here on fark can shed some light on.

I was sleeping on a Continental flight from Little Rock to Houston. I woke up and my stomach was in my chest, like when you're on one of those tower of terror or dungeon drop rides at an amusement park. The plane felt like it was just dropping out of the sky. Everyone started cursing and screaming.

It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out.  Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."

I muttered to myself "That's how Goose died." and the guy next asked me frantically "Who's Goose? is that a friend of yours?" He hadn't seen the movie.
 So fark pilot folks my question is this- I thought jet wash dissipates pretty rapidly. So how close were we to another jet for jetwash to cause what happened? And did the jetwash cause the engines to stall, or was a rapid descent done to avoid a stall?


Wake turbulence descends through the air column as it dissipates, so you can be a fair distance (1000-1500 ft vertically, 1-2 miles horizontally) away from the generating aircraft  and still feel the effects, especially if you are following or overtaking it at a lower altitude.  The descent was most likely an attempt to get below the turbulence. Think of the wake vortex descending left to right (\) and your aircraft descending right to left (/), the shortest way through the "danger zone" will make an X shape.  That said, unless it was an extreme case,  wake turbulence at altitude is more on an annoyance than a safety issue.

Per the engine question; even if the engines had quit, which they most assuredly didn't, you would not plummet from the sky.  In fact, if you had on noise cancelling headphones you probably wouldn't even notice.
 
2013-05-01 12:59:57 AM

thedumbone: Lsherm: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Put me down for human error (only because it usually is), or control system malfunction.

You've got 20,000 pounds of thrust counteracting that, at least for a little bit.  It only impacted nose first once it got the 10 milliseconds of control back, at which point I'm sure all that cargo shifted to the front.

Thrust doesn't work that way.  Aircraft are design to minimize pitch changes due to thrust, with the exception of certain seaplanes.

Also, you don't get "control back" until you get speed back, and that doesn't happen until the nose drops.

FizixJunkee: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Inertia.

Inertia doesn't cause a aircraft to change from nose-up to nose-down - it tends to keep things where they are.


Did that damn airplane look like it was minimizing a pitch change?
 
2013-05-01 01:02:30 AM

Peki: Warthog: But then they landed.  In the middle of a herd of angry west Texas steer.  They ended up climbing what passed for a tree in that part of Texas -- a scrawny thing full of thorns -- and ended up sustaining greater injuries from the tree while evading the bovines than they did in the ejection.  Everyone in the unit thought this was hilariously funny.

I've always wondered about these stories. The line I was told was that ejection seats generally compress your spine so badly in the attempt to get you TFO of the way that walking afterwards is pretty much impossible.

The vid is just gnarly. Thanks for the Farkers who explained cargo shift, because my family has been in the aerospace business long enough that I know there's not much mechanical that can cause that.


That was true of the old F-111.  A number of pilots were actually, measurably, shorter after ejecting and had life long spinal problems.  The newer seats such as the ACES II do not have this problem.  They ramp up their speed over a short time to accelerate the pilot out of the aircraft rather than reaching full thrust instantly.  That protects them from the instantaneous G forces that caused the spinal problems.
 
2013-05-01 01:03:27 AM

Tony_Pepperoni: Anyone else notice the time stamp on the video?


Anyone else notice the dog yelping when the guy started to back up?  He must have stomped on it or something.
 
2013-05-01 01:03:33 AM
To anyone who is a pilot (or know about such things), why didn't he put the nose down and power up? If you can see you're about to be in a stall situation, that's fairly easy to determine in VERY short order.
 
2013-05-01 01:05:28 AM
 
HBK
2013-05-01 01:05:38 AM
Thank you guys for all the explanations. Sorry I derailed the thread a bit, it was something I'd been curious about for a while.
 
2013-05-01 01:09:09 AM
Horrifying video. Wonder if any Farkers have unknowingly been in this aircraft -- she started life in the early 90s as an Air France Combi (2/3 passenger, 1/3 cargo on the main deck), and wasn't converted to a BCF until about 2007, so that's 14+ years in passenger service.
 
2013-05-01 01:09:30 AM

Lsherm: thedumbone: Lsherm: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Aircraft are design to minimize pitch changes due to thrust, with the exception of certain seaplanes.

Did that damn airplane look like it was minimizing a pitch change?


Nope, but thrust had nothing to due with it.  A center of gravity that wasn't in the tail did.

Put another way: once it stalled, it became a glorified lawn dart, with weight in the nose and fins on the tail.  The elevator must have been acting to bring the nose up, and then the nose fell once the elevator/wing became ineffective.
 
2013-05-01 01:09:46 AM

ThisIsntMe: SpikeStrip: remus: SpikeStrip: remus: this isn't going to be pretty.

opposed to what?

// have actually had a conversation, while eating lunch, that included the words "what's that?  I think it's a piece of tongue..."
// continued eating lunch...

what happened next?

Dessert, I'm guessing.


Well, what else would you do?  It's not like you should skip the pudding.

Seriously, the first time I worked the accident investigation lab, I couldn't eat that day.  By the time I had done it a few times, I could eat while working.  You just get used to it.
 
2013-05-01 01:10:10 AM

thedumbone: Put me down as the (first?) to say - NOT a load shift.

If the airplane was tail-heavy enough to overwhelm the elevator, it would have come down tail first.  It impacted nose first.

Put me down for human error (only because it usually is), or control system malfunction.


Once it stalled it was effectively free falling. In freefall you have zero g, so where the weight is suddely doesn't matter. Looks like they went over sideways where they would have been ballistic where you still have zero g so again the weight being at the back wouldn't have mattered.
Once the nose was down and they started to get some lift, and therefore g, back the load if it was loose could have rolled to the front where it would now stop them pulling up, not that they had enough altitude anyway.
 
2013-05-01 01:11:02 AM
Growing up I've had a few friends who lost their dads to military aircraft crashes.  My old man was in 3 separate helo crashes.  Just... fark....

/need to go have a drink and a tear
//farking memories
 
2013-05-01 01:11:27 AM

neilbradley: To anyone who is a pilot (or know about such things), why didn't he put the nose down and power up? If you can see you're about to be in a stall situation, that's fairly easy to determine in VERY short order.


That's just what they'd be expecting.

/I'm sure that they tried to do exactly that, but were unable to for unknown reasons.
 
2013-05-01 01:11:55 AM

HBK: It felt like we were falling for 30 seconds, but I'm sure it was probably less than 10 seconds. The plane leveled out. Fifteen minutes the stewardess comes on the intercom and says "Sorry about the turbulence. We flew through some jetwash."


You can run into wind shear in otherwise quiet air. One moment the plane is flying along at 400 knots then the wind direction changes and now the plane is flying at 350 knots and stalls.  Since you have sufficient airspeed the pilot still maintains control, but you sink like a stone.  If you think in level flight the lift is just enough to keep the plane level.  If the apparent airspeed or angle of attack changes suddenly, then you can have substantially less lift than you need to keep the plane in the air.
 
2013-05-01 01:14:11 AM

HBK: Thank you guys for all the explanations. Sorry I derailed the thread a bit, it was something I'd been curious about for a while.


This one doesn't mind. Like I said somewhere, I like Fark because of all the goodies you learn in the comments. The article I couldn't give a fark less about (except for pure social currency and knowing what's going on in the world).

And the best part about threads like these is you usually get a few techies/SMEs/etc. who outgeek each other. Even if they don't agree, you still get a pretty decent look at both sides of the argument enough to form your own opinion about it.

/and any BS gets filtered REALLY quickly
 
2013-05-01 01:14:27 AM

neilbradley: To anyone who is a pilot (or know about such things), why didn't he put the nose down and power up? If you can see you're about to be in a stall situation, that's fairly easy to determine in VERY short order.


If the load has move backwards, or was loaded too far back, the controls are not enough to put the nose down.
A few years ago a commuter prop had too much luggage in the tail and did exactly the same thing on takeoff.
 
2013-05-01 01:15:12 AM

thedumbone: Lsherm: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Put me down for human error (only because it usually is), or control system malfunction.

You've got 20,000 pounds of thrust counteracting that, at least for a little bit.  It only impacted nose first once it got the 10 milliseconds of control back, at which point I'm sure all that cargo shifted to the front.

Thrust doesn't work that way.  Aircraft are design to minimize pitch changes due to thrust, with the exception of certain seaplanes.

Also, you don't get "control back" until you get speed back, and that doesn't happen until the nose drops.

FizixJunkee: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Inertia.

Inertia doesn't cause a aircraft to change from nose-up to nose-down - it tends to keep things where they are.


Wow lot of armchair flightsim pilots in the comments tonight.

You are correct. Inertia has nothing to do with it. It has everything to do with the laminar to turbulent flow of air, the former generating more lift. The wing design of that aircraft is very similar to the modern 747-8 series which employs slats and Kruger flaps which send that transition point way far back so that you can achieve very very high angles of attack and reduced airflow conditions before the turbulent flow creeps too far back up the camber, reducing lift and increasing stall risk. As seen in the video, she already had a huuuuge AoA with big big wings and slats full out so it wasn't a controls issue - she had to have enough control to get into that configuration. And her engines were screaming. Highly highly likely a load shift caused by something not being secured or improper loading to begin with once she cleared ground effect and those big muscles on her wings took over and lost the arm wrestling match.
 
2013-05-01 01:17:17 AM
phalaeo:This video has a graphic of how load shift works, for anyone who wants to take a look.  It's not the best graphic, but it gives a basic idea of how it happens.

...and caused the engines to stall..." ARRGH!  NO!

The WINGS stalled.
 
2013-05-01 01:17:18 AM

neilbradley: To anyone who is a pilot (or know about such things), why didn't he put the nose down and power up? If you can see you're about to be in a stall situation, that's fairly easy to determine in VERY short order.


You won't be able to if your cargo is all aft of your center of gravity. My old flight instructor died this way in a 172 believe it or not. It can happen to the best of us if we're not careful.
 
2013-05-01 01:17:45 AM

Flint Ironstag: thedumbone: Put me down as the (first?) to say - NOT a load shift.

Once it stalled it was effectively free falling. In freefall you have zero g, so where the weight is suddely doesn't matter.


Physics doesn't work that way on things with air resistance.  They tend to fall heavy-part first.

Build a paper airplane.  Check that it flies normally.  Tape a bunch of coins to the nose/tail and throw it towards the ceiling.  Notice now it crashes.

Now, a paper airplane is more Newton that Bernoulli, but the difference is moot when you're stalled anyway.
 
2013-05-01 01:21:55 AM

thedumbone: Charlie Freak: thedumbone: Put me down as the (first?) to say - NOT a load shift.

The tailplane's natural state is to fly upside down - in normal flight it is actually producing lift that causes a tail-down moment. When the main wing stalls, the tail often stalls as well, either due to the same low speed or because it is in the buffeted slipstream from the wing. The loss of this tail-down moment causes, you guessed it, a nose-down moment. Lower altitude, less time, and the tail-first thing might have played out, but there are a lot of other dynamics at play here as the wings and horizontal stabs alternately tried to go flying again.

The tail is designed to stall after the wing.  A tail stall is a whole different beast and rarely happens outside of icing conditions.

In any event, a stalled tail is producing effectively zero lift.  A flying tail, with the elevator forward, is trying to push the nose down.  A stalled tail would be LESS likely to drop the nose than a flying one.

/CFII, AMEL ASEL, 2000 hrs


Bingo. If your tail is stalled, you're in a whole new and exciting world of aerobatic flight, whether your rig is rated for it or not. And if that's not your intent, soiled underwear to go along with it.
 
2013-05-01 01:22:49 AM

flightmonkey88: Here is another unsettling bit, That bird went down on the edge of an old russian minefield at the end of the runway


damn, because sometimes you are just not quite farked enough already...
 
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