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Airbus A320 crashed in Southern France

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Airbus A320 crashed in Southern France

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Old 25th Mar 2015, 00:38
  #401 (permalink)  
 
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Dear OLD BOEING DRIVER:

Your question was valid. The response by the one poster was horrid. It seems to be deleted by now. Another post by PORTVALE was polite and answered the question.

I would not expect someone who flys for one airline to know what is used at another airline. BUT I DO EXPECT REASONABLE QUESTIONS asked nicely to be answered and not shot down.

IF someone has flown 4 different types of jets, and not happened to fly an airbus 320 owned by germanwings, it is a fine question.

We have fleets of planes, some have FULL FACE MASK, others have oxygen masks and goggles. ( I prefer the masks and goggles).

IF one pilot left the flight deck for any reason and the OTHER pilot was not on oxygen and something happened, OOOPS, BAM.

It is easier to go on oxygen with just a mask. What are the european regulations about oxygen and one pilot leaving cockpit?
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Old 25th Mar 2015, 00:43
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Sky high

Thanks for your response. We can all learn something from each other.

And, thanks to Portvale too.
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Old 25th Mar 2015, 01:03
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Is it possible that, for some reason, they didn't know they were descending?
Possible? Maybe... distraction / pre-occupation with an unrelated problem is not unheard of, and well documented (Everglades) - but one would think unlikely in this day and age - especially with modern bells 'n whistles.

But both pilots simply overcome by hypoxia so quickly also seems unlikely, on the face of it.
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Old 25th Mar 2015, 01:04
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"In default of a timestamp, I should have looked at the latitude reading" @AirScotia - the 'mtime' column in that graphic is the time stamp (unix format seconds since 00:00:00 1st Jan 1970) converters are available online
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Old 25th Mar 2015, 01:06
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Regarding the discourse on crew oxygen....My preflight oxygen system check was given more time and attention,after an experience,in Havana.
The crew oxygen had been changed,at European base,before previous transatlantic flight. The valve on the crew oxygen bottle,not accessible to crew in flight,had not been reopened!
Needless to say,had there been a decompression on the previous flight,the pilots would have been rendered unconscious...
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Old 25th Mar 2015, 01:07
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Sky High

The reason behind my question about the full face masks was relating to pilot incapacitation due to smoke or fumes in the cockpit, causing eye irritation or temporary blindness.

They may have been on O2, but unable to see anything and trying to get to a lower altitude. Maybe pretty busy along that time, as well.

I think someone a few pages back touched on this concept
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Old 25th Mar 2015, 01:44
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V/S Values

When looking at the V/S values derived from the FR24 data we will need to take into account that this data is not recorded in a way that allows to have accurate data to derive a precise sink rate from the recorded Mode-S data.


Neither the time stamps / intervals nor the resolution is up to that task. Therefore you can see a fluctuation on the V/S data that might not be there.


The track on the other hand clearly shows that the plane was on A/P.
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Old 25th Mar 2015, 01:53
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skyhighfallguy,

I would like to know which model engine is on this bus. But gee, because I have never been employed by germanwings, I would look dumb asking, right?
No, not really, the engines on this A-320 are CFM56-5…
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Old 25th Mar 2015, 02:01
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Having done the hyperbaric chamber training previously I have a few observations that we were told during the course.

Many are using the term "explosive decompression". We were advised that this term is incorrect; if you have had an explosion then that is a totally different problem. The term used is "rapid decompression" (note the title of the training video in post #224). This is defined as a total loss of pressure in less than approx. 14 seconds. The time used in the definition is based on the length of time it takes for oxygenated blood to circulate around the body and return to the lungs for replenishment with oxygen.

Secondly, most O2 masks are set by default to diluter demand. If the masks are donned in an unpressurised aircraft at FL380 they will not provide sufficient O2 for the crew as there is insufficient partial pressure to breathe. The mask must be switched to the emergency setting (unless A320 has a different system) to provide ram air O2 to enable breathing. If this was not known or done by the crew then the mask would be of little use.

While useful consciousness at FL380 is 12-14 seconds these figures are based on being aclimatised at that altitude. In a rapid decompression that time can be reduced to as little as 4-5 seconds due to the effects of numerous physiological effects such as 'The bends'.

Not speculating on the cause, just observations on others' speculation.
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Old 25th Mar 2015, 02:11
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A question for the A320 drivers: When descending through the Transition Level does the altimeter sub-scale setting automatically change from QNE to QNH or do you have to manually change it?

The reason I ask is that The Aviation Herald is reporting that: 'Radar data suggest the aircraft ... appeared to have leveled off at FL068 for one minute [prior to impact]'. The Grid Mora at the point the aircraft commenced descent is 6100. This suggests to me that the crew had set 7000 as a level off altitude for an emergency descent. 7000 is the Grid Mora at the descent point rounded up to the nearest 1000 and the difference between FL068/7000 could be due to the QNE/QNH difference.

This is consistent with the Rapid Depressurisation / Pilot Incapacitation scenario. The crew had enough time to wind down the altitude selector to 7000 and establish a descent, but subsequently became incapacitated before completing the rest of their emergency procedures. The aircraft descended on autopilot to 7000.

I can anticipate someone asking why didn't they set a higher altitude given that they were flying towards high terrain? Well at the point they descended they were very near the coast so high terrain was not an immediate issue. If depressurisation was the problem, then the immediate priorities are get on oxygen, establish comms with the other pilot and initiate an emergency descent. Setting the current MSA (6100 rounded up to 7000) is conceivable. I know, I know ... a lot of you will say just spin it down to anything, or anything but not below 10 000. But maybe in the stress of the moment 7000 was what was in their minds and that's what they first set. After the descent is established then you carry out the rest of the emergency descent procedures (declaring an emergency to ATC, adjusting the descent altitude, turning away from high terrain etc). Since none of these second phase procedures were performed, it would appear they've become incapacitated after the descent was initiated.
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Old 25th Mar 2015, 02:28
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I was just wondering, for those that understand the A320, is there anyway a rapid decompression could prevent the aircraft's radios from working?
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Old 25th Mar 2015, 02:32
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Your second point is not relevant in regards to A320 and most modern jet crew crew oxy masks, whereby the mask regulator supplies the appropriate oxy dilution or 100% automatically (NORMAL position).
It is relevant since 100% O2 still will not supply the O2 at sufficient pressure to assist breathing. 'Normal' is a mix of O2 and cabin air, '100%' is all O2, 'EMER' is O2 forced out of the mask under pressure to inflate the lungs at high altitude.

It is not a matter of the percentage quantity of O2 being delivered. It is the fact that the lungs cannot inflate to inhale the O2 with the reduced partial pressure at that altitude. I've flown GIV for 10 years. It has the standard 'modern jet' crew mask.

Your comment highlights my point about the masks that was pointed out to us during the course; most pilots think 100% will prevent hypoxia at high altitude. It won't.
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Old 25th Mar 2015, 02:39
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@daz211

I can't understand how an aircraft can descend so dramatically over 8 minutes with out ATC asking why or the pilot contacting ATC stating why.
ATC tried to contact them when they noticed the unauthorised altitude change... they didn't respond so an emergency was declared.

The pilots were likely unconscious and/or incapacitated by this stage...

"We have obtained copies of the contact between the control tower and the pilots of the plane. These show there was no contact with the plane after it started losing altitude and when the air traffic controllers tried to contact it there was no response."

http://www.theguardian.com/world/liv...s-live-updates
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Old 25th Mar 2015, 02:58
  #414 (permalink)  
 
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Freespeed2,

I've never heard of 100% being an issue for well executed emergency descent. If sustained unpressurezed flight at those levels, then yes 100% may not provide sufficient O2 for life.

You would hope that once you'd recognised the ECAM, donned mask, established comm, announced emergency descent, flicked the seatbelt sign on, and initiated the descent, the aircraft would be approaching the mid 20's within 2 1/2 mins and the 100% would have been enough to get you there without hypoxia setting in.

The primary function of the 'Emergency' setting as far as I know is for keeping the mask free of smoke. I'm certainly open to others opinions on this? Do I need to use 'Emergency' O2 at FL380???
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Old 25th Mar 2015, 02:59
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@freespeed2, your comment regarding marginal O2 partial pressure at FL380 is entirely correct. I think the official limit is FL400 for positive pressure breathing apparatus requirements. However, the TUC comment isn't: the 12-15 seconds at FL380 is not for an "acclimatised" body. If it was acclimatised, decompression wouldn't be a problem... get it? ;-)

It rather depends on what it is you're doing (physical activity), and on your physical predisposition. Oddly enough whether you're fat or lean makes no difference, there are other factors at play, many not well known to aviation/mountaineering medicine.

The point is, 15 seconds is a very short time if you're caught by surprise, and there's no time to debug a problem if there is one, e.g. an insufficiently opened O2 bottle valve (not that pilots could do anything about that anyway), or flow regulators in the wrong position etc. You simply don't get a second chance.
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Old 25th Mar 2015, 03:12
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What the flight path shows is consistent with the O2 bottle being shut off leaving enough O2 to initiate descent, then the pilots go incapacitated.

The high altitude chamber films show pilots recovering to a walking, talking state quickly after getting the mask back on - - after maybe half a minute without.

After several minutes of high altitude hypoxia, you will not suddenly regain your piloting ability when below 14,000.

Case in point: An Argentinian glider pilot woke up in a field with the glider missing the wing outer panels after being sucked up into a CB. He had no memory between the time he pulled the dive brakes and when he woke back up.

My O2 system will run down sharpish if I forget to open the bottle, but it will show up on the flowmeter before I get very high.

Before the quick donning masks, one pilot was required to be wearing a mask and breathing with it above 30,000 or so . A closed bottle would be quickly apparent and an RTB would be initiated if it could not be turned on in the air.

Today crews are betting their lives and those of the pax that mx has opened the bottle if there's a depressurisation.

Helios lost that bet and we may be looking at a repeat.
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Old 25th Mar 2015, 03:12
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turbine d, thanks, cfm 56

old boeing...I understand exactly what you are getting at.


another poster, yaw string, indicated he checked his oxygen in havana after the inbound crew HAD NOT and found the valve OFF.

I've seen this too, esp after servicing. I am of the habit to make DARN SURE the oxygen system will work at 100 percent EMERGENCY and blow my lungs up and sound like the movie 2001 space odyssey .

this might have been part of the problem and I hope the oxygen service records will be released soon.
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Old 25th Mar 2015, 03:17
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Originally Posted by physicus
...However, the TUC comment isn't: the 12-15 seconds at FL380 is not for an "acclimatised" body. If it was acclimatised, decompression wouldn't be a problem... get it? ;-)
Fair point. Acclimatized is probably the wrong term. What I was trying (poorly) to explain is that the 12-14 seconds UC is a notional figure based on the circulatory period of O2 around the body. However the lecturers on the high altitude course were adamant that it is a lot less during rapid decompression. Nitrogen in the blood turns to a gas (the bends) which causes blockages of the blood supply thereby reducing the length of UC. They listed multiple other unpleasant physiological effects that are best not recounted here.
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Old 25th Mar 2015, 03:56
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ED alt window setting

Just curious, are European pilots taught to know the MSA and to put it in the Alt window for an emergency descent? Or just spin and get it down?
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Old 25th Mar 2015, 03:59
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When looking at the V/S values derived from the FR24 data we will need to take into account that this data is not recorded in a way that allows to have accurate data to derive a precise sink rate from the recorded Mode-S data.

While I agree the reported figures are subject to variation, in my experience, Mode-S V/S data varies not by the thousands, but hundreds in a steady climb or descent.

The track on the other hand clearly shows that the plane was on A/P.
Possibly, considering the difficulties our guys apparently had in maintaining a steady ROD as per LR's suggestion:

Yes, and with very distressed flight-deck crew continuing on what had looked like a reasonable forced landing site. Okay to keep descending.
Could have been the MCP mode they were in, VNAV or even HDG if the winds were constant through the descending layers. I know these are B terms, apologies if I'm not up on my Airbus autoflight vernacular.



I guess we can all make mistakes, but from an aircraft maintenance point of view, I've been told regularly that Lufthansa Technik is top notch.

Is it possible that, for some reason, they didn't know they were descending?
I seriously doubt it. Too many cues to miss. Aside from the instruments - at very least they should have had the standby horizon and altimeter - there is an obvious attitude change, pressure changes along the way, and sound. Then again, with masks on, it could be missed if they were task saturated.
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