Germanwings A320 down in French Alps

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Germanwings A320 down in French Alps

Postby AndyToop » Tue Mar 24, 2015 11:26 am

http://www.bbc.co.uk/news/live/32030778

Current reports are no survivors expected. :(

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Re: Germanwings A320 down in French Alps

Postby tds » Tue Mar 24, 2015 11:48 am


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monchavo
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Re: Germanwings A320 down in French Alps

Postby monchavo » Tue Mar 24, 2015 12:46 pm

Currently top billing across media all over Europe. Unsurprising given the significance. Isn't Helios the last big passenger bird to go down?
Be interesting to see what the cause was. Rescue teams en-route to a "difficult to access location" apparently.
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Re: Germanwings A320 down in French Alps

Postby 3WE » Tue Mar 24, 2015 1:33 pm

A lot of recent incidents could unfortunately be dismissed as coming from not-so-first-world crews and/or low-time-less-sharp regional crews...

Not this one.
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Re: Germanwings A320 down in French Alps

Postby AndyToop » Tue Mar 24, 2015 2:04 pm

Oh the joys of continuous news reporting:-
"The plane went down at approximately 10:45 local time GMT."

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Re: Germanwings A320 down in French Alps

Postby J » Tue Mar 24, 2015 3:20 pm

Recent Summaries:

625 pm crash site located near ski resort of Pra Loup at about 2,000 meters

640 pm photos provided of rescue teams at alps

732 pm no visible deviation in flight path

8 00 pm summary of crew / plane;

A320 built for LH in 1991, transferred to Germanwings in 2001 - last routine check was yesterday 23 March in Dusselforf, last major check summer 2013

Captain had 10 years with LH and Germanwings - 6,000 hours in the A320

http://www.firstpost.com/world/live-cap ... 70837.html

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Re: Germanwings A320 down in French Alps

Postby flyboy2548m » Tue Mar 24, 2015 3:58 pm

No worries, Evan and Gabriel will the answer by the end of the day.
"Lav sinks on 737 Max are too small"

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Re: Germanwings A320 down in French Alps

Postby J » Tue Mar 24, 2015 6:03 pm

Flight Data Recorder has been recovered. Latest reports say no distress message was sent and that the plane appeared to be in a rapid but controlled descent for 8 minutes prior to impact.
http://www.foxnews.com/world/2015/03/24 ... -on-board/

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Re: Germanwings A320 down in French Alps

Postby 3WE » Tue Mar 24, 2015 8:42 pm

No worries, Evan and Gabriel will [have] the answer by the end of the day.
Indeed.
This has to be a freak swiss-cheese scenario to make any sense. It seems like a crew incapacitation event but somebody had to input a command to descend. The descent appears to be open (idle thrust/speed on elevator) with lateral guidance. Perhaps, on the verge of hypoxia, they selected OP DES and spun down to 6,800' and left in the current airspeed, then lost consciousness. AvHerald reports that the A/C appears to have leveled off at 6,800' about a minute prior to impact.

The trouble with this is the clear warnings (crickets, master warning, pressurization page up on the SD) when the cabin alt goes above 9550'. There's still plenty of time to don masks and deal with the issue. So what's the next slice of cheese here? A latent malfunction of the crew 02 system? Flawed procedure delaying the masks? Situational awareness?

How could this happen to a Lufthansa crewed and maintained flight? I hope this doesn't lead to another Air France-style revelation...
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Re: Germanwings A320 down in French Alps

Postby J » Tue Mar 24, 2015 10:11 pm

A video that may support Evan's analysis.

http://video.foxnews.com/v/4132057928001

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Re: Germanwings A320 down in French Alps

Postby 3WE » Tue Mar 24, 2015 11:07 pm

Yeah, but a few too many whys and too premature...

Why 6_00 feet and not something higher where you can still be awake and not hit mountains?
Why a course change?
The descent rate is not all THAT remarkable (i.e. who says it's an emergency descent for depressurization).
Was that blip on the flight tracking website (14,000 fpm descent rate- but no real altitude change) something major that also caused a hiccup in the static system?
Why didn't they just cruise on till fuel exhaustion like most other insidious decompression cases?
Why couldn't it be one of about 100 potential catastrophic failures- engine explosion destroys controls, in-flight-structural-break-up (ok, bend up), some other control failure, explosive device, terrorist incident...

etc.

With a little luck, there may be lots of insight from the recorders in the near future.
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Re: Germanwings A320 down in French Alps

Postby Robert Hilton » Wed Mar 25, 2015 12:35 pm

I'm sure the aviation safety boards will consult Evan on the possibilities. He seems to have it down pat..............

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Re: Germanwings A320 down in French Alps

Postby AndyToop » Wed Mar 25, 2015 4:34 pm

This has to be a freak swiss-cheese scenario to make any sense.
Aren't they all (usually need at least two slices e.g. after pilot fed dog, dog's mouth was full so it could not bite pilot before he pressed the button)
It seems like a crew incapacitation event but somebody had to input a command to descend.
Agreed as long as that word "seems" is there
The descent appears to be open (idle thrust/speed on elevator) with lateral guidance. Perhaps, on the verge of hypoxia, they selected OP DES and spun down to 6,800' and left in the current airspeed, then lost consciousness. AvHerald reports that the A/C appears to have leveled off at 6,800' about a minute prior to impact.
Radar data

Radar data suggest the aircraft had reached FL380 about 3 minutes prior to leaving FL380 and descended from FL380 through FL110 in 8 minutes (average rate of descent 3375 fpm). The aircraft appeared to have levelled off at FL068 for one minute while on a northeasterly heading of 26 degrees true, mountains rise up to 8900 feet about 1nm north of the last reported aircraft position.
This is where it all gets far too wooly.
- The 8900 ft mountain 1kt due north of the last report is irrelevant, because a simple tan(26) shows it would miss that easilly.
- A quick look at a contour map of the area shows that the only peak rising above 2000m between the last reported position and the crash site is 2010m and is closer to the last reported position than the crash site.

So there is nothing about the terain that suggests that the plane would need to have done anything but descend between the last report and the crash site.

The level off is based on the difference in height between the last report FL068 (6800ft) and the reports of debris being found at 2000m (6500ft)
- First off its secondary radar data, i.e. it is transponder data received from the plane.
- Transponder altitude is PA, depending on the actual pressure at the last reporting point the plane could have been quite a bit higher than 6800 ft
- dependant on the actual pressures at FL380 and FL068 the true descent rate could be a bit higher or lower
- The rock they hit rises almost vertically from 5000ft to over 8000ft
- The report of finding wreckage at 2000M came from the helicopter search. My guess given the images of the wreckage is that this is at best "ballpark" and very likely to be based on the pilots local knowledge rather than any instrument reading.
Given the vaguaries of the start altitude MSL, end altitude MSL and true descent rate, it is quite possible that the plane was still in the same descent profile all the way from the last reporting point to the crash.
The trouble with this is the clear warnings (crickets, master warning, pressurization page up on the SD) when the cabin alt goes above 9550'. There's still plenty of time to don masks and deal with the issue. So what's the next slice of cheese here? A latent malfunction of the crew 02 system? Flawed procedure delaying the masks? Situational awareness?
The trouble with an explsoive decompression event at 38000ft you only have a few seconds of usefull conciousness - towards the lower end in a state of high stress and activity and its likely that the rapidly cooling air just brought the clouds into the cockpit obscuring visibility. The only two other cases of rapid decompression I can think of atm are the BA (18,000ft) and aloha (24,000ft) at these altitudes the usefull conciousness is measured in minutes not seconds. Take a look at this mask demo When the video kicks in at 3 seconds and he is already reaching for the mask. Its on and flowing at around 11 seconds and he wasn't wearing a headset. In other words in the most optimal conditions it will take 8 seconds - add in reaction times, headset removal etc. and there is not "plenty of time".
How could this happen to a Lufthansa crewed and maintained flight? I hope this doesn't lead to another Air France-style revelation...
If it was explosive decompression at 38,000ft - it wouldn't matter who had trained the crew, the odds of getting the mask out, adjusted for headset and on securely enough for the 02 to be headed into your lungs and not out the sides quickly enough is slim. This guy is an airforce pilot from the U2 program and the mask drops right in front of his face - and he still can't get it on without assistance.

My guess. Something happened at the point the -14,000ft vert speed was reported. That triggered an explosive decompression. One of the crew managed to get as far as iniitiating the descent but was unconcious within seconds of doing so. The altitude dialled in was < 6000ft.

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Re: Germanwings A320 down in French Alps

Postby 3WE » Wed Mar 25, 2015 7:27 pm

I don't suppose there's a link somewhere to one BIG HUGE table on the effect of hypoxia...

...Here's where I'm going with this...you get the descent started and pass out...shouldn't you wake up somewhere in the upper teens???

I think I've heard (possibly wrong) that passengers will generally survive a decompression and "immediate" emergency descent with no supplemental O2.

I recognize that this whole thing is complicated as hell....10,000 feet for sustained, sharp mental function...Possibly 'drunk'-but-still-basically-correct function to 15K with sustained performance? Still generally conscious but kind of drunk off your a$$, largely incapable of decent function through 20K?

...All of this being rough averages with a fair bit of person to person variability and depressurizing being different from re pressurizing...etc. etc. etc.

Anyway- if the plane was pretty functional, is it reasonable to expect the guys to wake up sometime well before 6,800 feet?
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Re: Germanwings A320 down in French Alps

Postby monchavo » Wed Mar 25, 2015 8:00 pm

Hello chaps.

Some questions if I may

- Very few photographs of the site of impact but a great deal of the debris field - I can find no verifiable image of the supposed "point of impact".

- Debris field is of course fascinating, with many many small pieces . I have been looking for patterns of distribution in the images that I've seen - I can find none (unsurprising, I am not trained in these matters)

- Not seen any scorch marks or fire damage - would welcome any images of such

- Hollande foolishly indicated that the casing of the FDR had been found but "there was nothing inside it". I don't agree this with revelation, you shouldn't tease the public like this.
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Re: Germanwings A320 down in French Alps

Postby AndyToop » Wed Mar 25, 2015 8:22 pm

Return to consciousness depends on how much oxygen starvation your brain has suffered. So a gradual increase in cabin altitude to something like 25,000 feet over a minute and then another couple of minutes to get down to 10,000 you will have very mild hypoxia and may not even pass out. If you go from 8,000 to 38,000 in seconds you will go into a coma within a minute and start to suffer permanent brain damage within 5 minutes. Source = my dad. GP retired.

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Re: Germanwings A320 down in French Alps

Postby AndyToop » Wed Mar 25, 2015 8:28 pm

Hello chaps.

Some questions if I may

- Very few photographs of the site of impact but a great deal of the debris field - I can find no verifiable image of the supposed "point of impact".

- Debris field is of course fascinating, with many many small pieces . I have been looking for patterns of distribution in the images that I've seen - I can find none (unsurprising, I am not trained in these matters)

- Not seen any scorch marks or fire damage - would welcome any images of such

- Hollande foolishly indicated that the casing of the FDR had been found but "there was nothing inside it". I don't agree this with revelation, you shouldn't tease the public like this.
On the mobile at the minute so can't find links etc. But see if you can find France2 video of the scene gives much better overview. Debris is all in very steep gulleys on a cliff. My own suspicion is it hit the cliff face higher up than in the pics and gravity has had more influence on the debris location than the impact.

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Re: Germanwings A320 down in French Alps

Postby 3WE » Wed Mar 25, 2015 11:33 pm

Why don't the engineers just program the FMS to do its own emergency descent to 12,000 or 14,000 or 15,000 or the MEA and then if you get your mask on or its a false alarm you just hit Gabe's click clack buttons and cancel it
Yes, I used the word "just" from the arm chair in my parlour but am also impressed at how risky Andrew is making the mask donning out to be...not as adequate as I'd like to see.
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Re: Germanwings A320 down in French Alps

Postby monchavo » Wed Mar 25, 2015 11:50 pm

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Re: Germanwings A320 down in French Alps

Postby 3WE » Thu Mar 26, 2015 12:07 am

Oh shit.... Gossip that a pilot was locked out... Probably what Monchie was reporting.
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Re: Germanwings A320 down in French Alps

Postby monchavo » Thu Mar 26, 2015 12:22 am

Oh shit.... Gossip that a pilot was locked out... Probably what Monchie was reporting.
Yes. I am not going to repeat it here. Astonishing how 36hrs on this kind of thing would leak from the investigation into the media.
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Re: Germanwings A320 down in French Alps

Postby monchavo » Thu Mar 26, 2015 12:50 am

And now it seems just an hour later this rumour is exploding over the news outlets.

I find it incredible that the cause of the incident would be leaked in this fashion. Is this a new media strategy to let it out in this way to minimise the impact of the story? Why - what's the PR angle of this approach? Does it reduce the "shame" on the brand? Slightly baffling.
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Re: Germanwings A320 down in French Alps

Postby AndyToop » Thu Mar 26, 2015 8:59 am

Why don't the engineers just program the FMS to do its own emergency descent to 12,000 or 14,000 or 15,000 or the MEA and then if you get your mask on or its a false alarm you just hit Gabe's click clack buttons and cancel it
Yes, I used the word "just" from the arm chair in my parlour but am also impressed at how risky Andrew is making the mask donning out to be...not as adequate as I'd like to see.
It's not that the mask donning in itself is not adequate. Just that at cruise and with an explosive/very rapid decompression the onset of hypoxia is measured in just a few seconds. Not at all the same as the gradual onset with nice warnings and gradual CA ascent you get with the failure to pressurise on the way up. Or the minutes you have to get your sh*t together in the teens and twenties. Once you get above the mid thirties most people will not be able to breath in at all, the air is literally sucked out of their lungs. I also saw something that said that a low enough pressure your lungs even work the wrong way round - taking oxygen from your blood and releasing it in gaseous form into your lungs. Need to check this one out with my dad.

Basically there are plenty o's scenarios where if you don't have the mask on already its already too late.

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Re: Germanwings A320 down in French Alps

Postby 3WE » Thu Mar 26, 2015 11:41 am

Indeed lungs could work in reverse. It's fundamental chemistry and concentration and partial pressure gradients and solution driven stuff. We only need your dad to know if the pilot is awake or not.

Like you illustrated, the dude at FL40 something failed in a simple task and knew ahead of time. BUT THEN throw in the shock factor and God knows what physical factors like a lurching plane and smoke and wind and dust....

Maybe Otto should be programmed to count to five and then initiate a brisk descent to the MSA and automatically squawk 7700. (With a big red button on the touch screen that says Click clack paddy whack, give a man the plane)
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Re: Germanwings A320 down in French Alps

Postby monchavo » Thu Mar 26, 2015 11:58 am

remarkable press conference with the Marseille prosecutor. He looked extremely stressed. Chaotic conference. Shouldn't have agreed to answer questions in two languages.
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