Author Topic: 737 down  (Read 2379 times)

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
737 down
« on: March 21, 2022, 08:47:13 AM »
737-800 down in China with 132 people on board
Developing  story

China Eastern: Plane carrying 132 people crashes in Guangxi hills
https://www.bbc.com/news/world-asia-china-60819760
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #1 on: March 21, 2022, 08:53:04 AM »
Video supposedly showing the 737 plunging at high speed straight down. Yikes

"Horrifying footage shows the Boeing 737 plummeting to the ground after falling from 29,100ft in a minute and a half."

https://www.youtube.com/watch?v=DDDiB1dOGgs
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #2 on: March 21, 2022, 08:54:55 AM »
JET CRASH China Eastern Airlines crash – Shocking moment Boeing 737 with 132 on board nosedives vertically into mountain at 400mph
https://www.thesun.co.uk/news/18014251/china-eastern-airlines-crash-jet-mountain/
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

Fly320s

  • friend
  • Senior Member
  • ***
  • Posts: 14,415
  • Formerly, Arthur, King of the Britons
Re: 737 down
« Reply #3 on: March 21, 2022, 09:36:54 AM »
Lose 29,000 feet in 90 seconds?  Intentional or inflight break-up.

Looks more intentional to me.
Islamic sex dolls.  Do they blow themselves up?

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #4 on: March 21, 2022, 10:13:48 AM »
Notice the speed suddenly dropping a bit right before increasing? In flight break up? Or maybe it occurred right after they throttled back for decent?

"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #5 on: March 21, 2022, 10:22:15 AM »
Or maybe a thrust reversal incident?
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

RocketMan

  • Mad Rocket Scientist
  • friend
  • Senior Member
  • ***
  • Posts: 13,578
  • Semper Fidelis
Re: 737 down
« Reply #6 on: March 21, 2022, 12:13:51 PM »
In that short snippet of video of the plane just before impact, it looked like the vertical stabilizer was missing.  It was hard to tell for sure, though, as the video was pretty poor quality.
If there really was intelligent life on other planets, we'd be sending them foreign aid.

Conservatives see George Orwell's "1984" as a cautionary tale.  Progressives view it as a "how to" manual.

My wife often says to me, "You are evil and must be destroyed." She may be right.

Liberals believe one should never let reason, logic and facts get in the way of a good emotional argument.

dogmush

  • friend
  • Senior Member
  • ***
  • Posts: 13,671
Re: 737 down
« Reply #7 on: March 21, 2022, 01:31:00 PM »
If it had much of a sustained vertical dive, much less a powered vertical dive, It would be well past Vmo (maximum operating speed) and could have already had structural failure even if it had started the dive in good shape.  Especially as it got lower at high speed.

It looks like Vmo for a 737-800 is 340ktsCAS/.82 Mach.  I'd expect if it held .85-.9 Mach as it went under 15,000 or so feet it'd start to come apart.

Ben

  • Administrator
  • Senior Member
  • *****
  • Posts: 45,746
  • I'm an Extremist!
Re: 737 down
« Reply #8 on: March 21, 2022, 02:22:18 PM »
I wonder if this might end up being similar to Alaska Air 261. I was on the response to that one. As I recall, their first dive was pretty much nose down near vertical, from which they recovered, then they went inverted and back in. The horizontal stabilizer system was the problem there.
"I'm a foolish old man that has been drawn into a wild goose chase by a harpy in trousers and a nincompoop."

BobR

  • Just a pup compared to a few old dogs here!
  • friend
  • Senior Member
  • ***
  • Posts: 7,246
Re: 737 down
« Reply #9 on: March 21, 2022, 02:50:02 PM »
I wonder if this might end up being similar to Alaska Air 261. I was on the response to that one. As I recall, their first dive was pretty much nose down near vertical, from which they recovered, then they went inverted and back in. The horizontal stabilizer system was the problem there.

Alaska air was an MD80. There have been a couple of (not sure how many) reports of 737s going straight down after a uncommanded rudder hardover malfunction. One of the was in Pittsburgh IIRC. https://en.wikipedia.org/wiki/Boeing_737_rudder_issues

The 737 has had its share of issues, I remember a couple that lost an engine (as in fell off) in flight. The rudder hardover issues and then the 737 Max goundings.

bob


WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #10 on: March 24, 2022, 12:26:43 PM »
Reported the cockpit recorder has been found. Hopefully it can answer some questions

Also
Quote
The radar data shows the plane reaching maximum descent speeds of 31,000 ft per minute - or 157m per second.

"This is extremely excessive and not something we would normally see in any sort of flight. The aircraft would have been almost vertical," says Dr Sonya Brown, an aviation expert from the University of New South Wales.

At about 7,000-8,000 ft from the ground, there was a slight upturn, the data shows.

But then it continued it's high speed plummet to the ground.
https://www.bbc.com/news/world-asia-china-60856855
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

RocketMan

  • Mad Rocket Scientist
  • friend
  • Senior Member
  • ***
  • Posts: 13,578
  • Semper Fidelis
Re: 737 down
« Reply #11 on: March 24, 2022, 02:12:41 PM »
157 meters per second translates to about 565 km/hour or 351 mph.  Not that fast for a 737-800, even at lower altitudes.  Cruise at altitude is 0.785 Mach, and that works out to about 590 mph.  I wonder how correct the FlightRadar24 data is?
If there really was intelligent life on other planets, we'd be sending them foreign aid.

Conservatives see George Orwell's "1984" as a cautionary tale.  Progressives view it as a "how to" manual.

My wife often says to me, "You are evil and must be destroyed." She may be right.

Liberals believe one should never let reason, logic and facts get in the way of a good emotional argument.

sumpnz

  • friend
  • Senior Member
  • ***
  • Posts: 8,304
Re: 737 down
« Reply #12 on: March 25, 2022, 02:42:11 AM »
157 meters per second translates to about 565 km/hour or 351 mph.  Not that fast for a 737-800, even at lower altitudes.  Cruise at altitude is 0.785 Mach, and that works out to about 590 mph.  I wonder how correct the FlightRadar24 data is?

That was the vertical component of the velocity.

RocketMan

  • Mad Rocket Scientist
  • friend
  • Senior Member
  • ***
  • Posts: 13,578
  • Semper Fidelis
Re: 737 down
« Reply #13 on: March 25, 2022, 09:58:55 AM »
That was the vertical component of the velocity.

Yes, headed almost straight down at around 350 mph.  I'm thinking it wouldn't have been shedding parts at that velocity.
If there really was intelligent life on other planets, we'd be sending them foreign aid.

Conservatives see George Orwell's "1984" as a cautionary tale.  Progressives view it as a "how to" manual.

My wife often says to me, "You are evil and must be destroyed." She may be right.

Liberals believe one should never let reason, logic and facts get in the way of a good emotional argument.

Brad Johnson

  • friend
  • Senior Member
  • ***
  • Posts: 18,030
  • Witty, charming, handsome, and completely insane.
Re: 737 down
« Reply #14 on: March 25, 2022, 10:13:29 AM »
Yes, headed almost straight down at around 350 mph.  I'm thinking it wouldn't have been shedding parts at that velocity.

Shouldn't be considering the cruising speed is around 520 mph.

Brad
It's all about the pancakes, people.
"And he thought cops wouldn't chase... a STOLEN DONUT TRUCK???? That would be like Willie Nelson ignoring a pickup full of weed."
-HankB

sumpnz

  • friend
  • Senior Member
  • ***
  • Posts: 8,304
Re: 737 down
« Reply #15 on: March 25, 2022, 10:13:45 AM »
Yes, headed almost straight down at around 350 mph.  I'm thinking it wouldn't have been shedding parts at that velocity.


Any parts it shed would have probably parted company when they overstressed the airframe trying to pull out of the dive.

RocketMan

  • Mad Rocket Scientist
  • friend
  • Senior Member
  • ***
  • Posts: 13,578
  • Semper Fidelis
Re: 737 down
« Reply #16 on: March 25, 2022, 10:17:43 AM »


Any parts it shed would have probably parted company when they overstressed the airframe trying to pull out of the dive.

If that actually happened.  There was that brief bobble in the dive, so maybe an attempt to pull out was made.  I haven't heard whether any major parts were found away from the impact site.  If there were, that would indicate parts coming off at high speed.
If there really was intelligent life on other planets, we'd be sending them foreign aid.

Conservatives see George Orwell's "1984" as a cautionary tale.  Progressives view it as a "how to" manual.

My wife often says to me, "You are evil and must be destroyed." She may be right.

Liberals believe one should never let reason, logic and facts get in the way of a good emotional argument.

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #17 on: March 25, 2022, 10:22:09 AM »
If that actually happened.  There was that brief bobble in the dive, so maybe an attempt to pull out was made.  I haven't heard whether any major parts were found away from the impact site.  If there were, that would indicate parts coming off at high speed.

The terrain in that area judging from videos appears to be quite rugged. Could be months, years, or even never in finding parts.
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

Unisaw

  • friend
  • Senior Member
  • ***
  • Posts: 1,415
Re: 737 down
« Reply #18 on: March 25, 2022, 04:35:05 PM »
Bloomberg is reporting that a piece of the jet was found about 6 miles from the crash site.  That piece had not yet been identified.
Well, if you have the sudden urge to lick your balls you'll know you got the veterinary version... K Frame

sumpnz

  • friend
  • Senior Member
  • ***
  • Posts: 8,304
Re: 737 down
« Reply #19 on: March 25, 2022, 05:19:01 PM »
If that actually happened.  There was that brief bobble in the dive, so maybe an attempt to pull out was made.  I haven't heard whether any major parts were found away from the impact site.  If there were, that would indicate parts coming off at high speed.

Not necessarily.  If they way overloaded the airframe pulling out of the dive they could lose parts just from that, even if speeds weren’t especially high.  Or if they were in a high AOA resulting in a stall it’s possible for flutter to occur (especially in an already overload damaged part) that could break it off at unremarkable speeds.

RocketMan

  • Mad Rocket Scientist
  • friend
  • Senior Member
  • ***
  • Posts: 13,578
  • Semper Fidelis
Re: 737 down
« Reply #20 on: March 25, 2022, 07:19:27 PM »
Not necessarily.  If they way overloaded the airframe pulling out of the dive they could lose parts just from that, even if speeds weren’t especially high.  Or if they were in a high AOA resulting in a stall it’s possible for flutter to occur (especially in an already overload damaged part) that could break it off at unremarkable speeds.

All very true.
If there really was intelligent life on other planets, we'd be sending them foreign aid.

Conservatives see George Orwell's "1984" as a cautionary tale.  Progressives view it as a "how to" manual.

My wife often says to me, "You are evil and must be destroyed." She may be right.

Liberals believe one should never let reason, logic and facts get in the way of a good emotional argument.

WLJ

  • friends
  • Senior Member
  • ***
  • Posts: 27,853
  • On Patrol In The Epsilon Eridani System
Re: 737 down
« Reply #21 on: March 25, 2022, 07:46:09 PM »
I wonder how correct the FlightRadar24 data is?

How about when it's hacked? https://youtu.be/Zlyw5bPXs0U?t=776
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us".
- Calvin and Hobbes

230RN

  • It's like swimming to shore in an ebb tide.
  • friend
  • Senior Member
  • ***
  • Posts: 18,826
  • Pushing back. Help me out, here...
Re: 737 down
« Reply #22 on: March 26, 2022, 02:29:59 AM »
Peer Beer review requested.

I read when the Challenger capsule hit the water the acceleration was 300g.

So I kinda wondered morbidly what the acceleration might have been in the recent 737-800 disaster.

I was a little uncomfortable with my logic in the following.

One g of acceleration is 21.94 miles per hour per second, per 'net lookup.

Fuselage length is 190 feet total stopping distance with no crater depth figured in as part of the stopping distance.  190 feet is .036 miles.

Time to stop is .036 miles / 350 miles per hour (IOW the time to go from 350mph to
 zero miles per hour)

This is .0003028 hours. In seconds this is .370 seconds.

Rate X time = distance

Rate = distance / time

mph per second = .036 miles / .370 seconds to stop = .097

I get mph/second = .097 mph/sec

21.94 / .097 = 226 gee without adding in the crater depth (unknown) as part of the stopping distance, which would reduce the acceleration by a factor of (fuselage length / ( fuselage length + crater depth)).

I think.

Terry, 230RN

« Last Edit: March 26, 2022, 07:11:26 AM by 230RN »

sumpnz

  • friend
  • Senior Member
  • ***
  • Posts: 8,304
Re: 737 down
« Reply #23 on: March 26, 2022, 02:47:00 AM »
150-250g is in the ballpark.

Many F1 drivers have survived 50g impacts, and an Indy car driver survived a 214g impact, but those last for a couple, maybe tens of milliseconds at most at that peak level.  The 737 (or Challenger) impacts were not only as high or higher peak, but lasted a lot longer (hundreds of milliseconds at least, likely 1000-2000 milliseconds).  It’s the duration that’s really deadly, more so than the peak.  Plus, airline pax aren’t nearly as well restrained, and there’s the whole fireball, and huge amounts of shredded metal going everywhere too.

Fly320s

  • friend
  • Senior Member
  • ***
  • Posts: 14,415
  • Formerly, Arthur, King of the Britons
Re: 737 down
« Reply #24 on: March 26, 2022, 08:18:01 AM »
Shouldn't be considering the cruising speed is around 520 mph.

Brad
Yes, headed almost straight down at around 350 mph.  I'm thinking it wouldn't have been shedding parts at that velocity.

350 mph in the thick air at low altitude is not the same as 520mph crusing speed at altitude.  The 350 has a higher "feel" on the plane.

The cruising speed of 520 is True Air Speed (TAS), not Indicated Air Speed (IAS).  IAS is the wind you feel when you stick your hand out of the window.  Flying 350mph at low altitude will result in a bunch of wind on your hand.  Take that same speed into space and you won't feel anything, that's TAS.

Even 350 in thick air is not an issue.  The 737 family has a maximum operating speed around 350 kts (402 mph).  So the 350 mph vertical speed probably didn't damage the plane. 

I
Islamic sex dolls.  Do they blow themselves up?