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Posted (edited)

Blancolirio's take on it:

 

(He explains that the turbulence encounter caused a flight path excursion in the low hundreds.

The subsequent 6000' 'plunge' was in fact a controlled descent.)

 

https://www.youtube.com/watch?v=0UYNFthOx1o

 

Edited by Garfly
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Posted

Turbulence from storm activity is pretty common in that part of the world and I cannot see any good reason to unbuckle the belt completely unless going to use the toilets.

It may be a hard lesson for some to learn, but I bet all the passengers on this flight will keep them buckled in future.

Cumulonimbus storm clouds can top out above 50,000ft, way higher than normal aircraft cruise levels and are certainly to be avoided.

Way back in 1954 a De Havilland Comet broke up mid flight due to excess stresses on the airframe when flying through a storm.

Posted

My flight from Mackay to SW of Rockhampton Brisbane Center was issuing strong turbulence advice to the high flyers.  There was crap low level turbulence considering the temp and wind direction and strength so must have been getting downdrafts deflected off the hills that I was feeling at times on both Saturday afternoon and Monday morning.

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Posted

Yes, one guy observed that no one who was buckled in was injured. Not surprising. Like you say, every single passenger from that flight is going to remain buckled in during flights from now on...

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Posted

The Comets broke up due to a design fault around the windows. Fatigue when a lot of pressure cycles have been attained.

If there was storms about it would be evident on the weather radar and the seat belt signs would have been  activated and a PA made. If it's Clear Air turbulence CAT. there's little or no warning and usually associated with Jetstreams which can reach over 200 knots and naturally turbulence at the boundaries, all around the jetstream occur.   Nev

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Posted

One observer said a pitch up then shaking before the drop. ??

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Posted

I believe the cabin pressue in the Comet was found to be too high which also put stress on the airframe which was not up to the task. It is sad that we have to learn from such tragedies, but fortunately airframes these days seem far more capable.

Cabin pressure and fatige caused the windows to pop as I understand it.

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Posted

The cruising height  for most of these planes is quite close to both stall boundaries, (VMo and Mmo)  Under those conditions an "upset" is quite likely in a turbulence event. Turbulence or control input will slow the plane down..   Nev

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Posted (edited)

Yes, I think the aircraft would have broken up before attaining that vertical speed.

 

(Blancolirio explains that the turbulence encounter caused a flight path excursion in the low hundreds.

The subsequent 6000' 'plunge' was in fact a controlled descent.)

 

 

 

Edited by Garfly
Posted

It's about the minimum height you'd lose in any upset  in the thin air where you're cruising.  Nev

Posted (edited)

And this CBC journalist while getting closer to the right ROD

insists that 2000 ft per minute is a 'catastrophic drop'.

(at 01:30 - it's not advisable to suffer the whole thing)

We need Blancolirio to explain that the 6,000' controlled descent happened 15 minutes after the turbulence encounter.

 

 

 

Edited by Garfly
Posted

Whatever the details, people smashed their heads on the ceiling. Lesson? Stay buckled up, no matter what the sign says.

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Posted (edited)

Not the first time a Singapore airplane has stalled at high altitude. 

They use a much tighter margin to determine max altitude than others ......

The 6,000' descent would be down to the next available altitude.

 

Edited by Deano747
Posted (edited)

I've heard a few reports from pilots that the weather radars are next to useless in the area with the tropical storms.

they are set up - and trained for north american weather patterns. and newly forming thunderstorms aren't picked up by it

Edited by spenaroo
Posted
22 minutes ago, spenaroo said:

I've heard a few reports from pilots that the weather radars are next to useless in the area with the tropical storms.

they are set up - and trained for north american weather patterns. and newly forming thunderstorms aren't picked up by it

Somewhat true for old generation weather radars, the one's I have a little experience with post 1990 are pretty good, and suspect the 777 in this incident was better again.

Comes down to interpretation though - how it is used and what avoidance action was attempted.

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Posted

Weather radar is specifically designed to show precipitation and dense clouds. You can pan up and down to determine vertical development   If you have no idea what you are doing you can mistake a lake for a storm cell.  Radar is ESSENTIAL for safe flight. Downwind of a big CB is also no place to be as you can get large hail in clear air..  You can also pick areas where a lightning strike is less likely  and avoid major cells in a frontal line.  I have NEVER gone through a thunderstorm cell . You may have to deviate well off track. but you do it IF you want to  manage risk..Nev

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Posted (edited)

From Reddit (so not the best source)

Quote
 
 

They definitely flew through something, this wasn't CAT, it was likely a cell that didn't paint much.

The Honeywell RDR-4000 radar doesn't do tilt settings, instead, it scans all tilts at once and displays weather as either "at your altitude", or "below you" (crosshatched out on the display). At tropical latitudes the tops of the cells are all ice crystals and don't paint much, I've seen a lot of cells that are clearly above FL400+ but are hatched out on the display. You go around everything even if it's hatched out when flying near the ITCZ. Fly around with max gain so the weak returns actually show up.

 

 

Also have to wonder if maybe they inadvertently had the WX display opacity turned down? Kind of a gotcha in the 777, you can dim the radar display on the ND to the point that it may not be apparent there's something painting. Most guys I know fly around with it on max brightness all the time and have that as part of their preflight flow.

 

From an article I was reading this morning

Quote

Speaking to Fox News, Captain Shem Malmquist, a pilot and instructor at the Florida Institute of Technology College of Aeronautics, suggested another theory.

 

“I have extensive experience flying Boeing 777s over the Bay of Bengal, the exact area that this occurred,” he said.

“When you look at a turbulence-type event, there’s only a few factors that can cause turbulence of this nature.”

Mr Malmquist said it could have been caused by a fast-flowing jet stream, but those are “normally closer to the poles, relatively speaking”.

He suggested it could also have been caused by flying close to a thunderstorm.

“One of the things that caught my eye is the knowledge that when you fly over the area of Bay of Bengal, it’s warm tropical waters, the thunderstorms don’t manifest the way they do in other parts of the world,” he said.

“Most pilot training is based on the kind of thunderstorms we see in North America. But thunderstorms over warm oceanic areas manifest significantly differently, and because of that the way the pilots are trained and even some of the automated radar algorithms can miss it and not depict the storm, and the next thing they know they’re flying right into it.”

 

Edited by spenaroo
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Posted

It's the Inter Tropic Convergence zone and is near the thermal equator. When I used to fly F 27's from Darwin to Baucau (Timor L Este) at certain times of the year the clouds went to over 60,000feet and looked like a wall of green Ice. Planes have disappeared without trace in that area.   Nev

Posted

I flew that route often,  20 or so years ago on British Airways 747s, always got seat 59a up the back next to the drink machine, did not even have to get out of my seat for a drink 🤩 

Brisbane to Narita Japan is another route that could get rough, too.

I ALWAYS wear set belts, regardless and never had a problem…..

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Posted

I hear this morning it hit an airpocket. There's no such thing.. Certainly attracting a lot of Media attention.   Nev

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Posted
1 hour ago, facthunter said:

I hear this morning it hit an airpocket. There's no such thing.. Certainly attracting a lot of Media attention.   Nev

 

Popular media has deep pockets.

 

 

(and shallow chat peeps )

https://www.youtube.com/watch?v=7rsB59MX8Xo

 

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