Airbus A320 crashed in Southern France

[Aeromar27]

Quote:
Decompression has been ruled out by GermanWings. This leaves me completely clueless.
source? press conference?

Philippa Oldham, Head of Transport at the Institution of Mechanical Engineers

I don't think it makes sense though as I don't think she has more information than the rest of the people not involved in the investigation do.

[Pace]

How on earth could they rule out depressurisation and crew incapacitation? There is no basis to do that at this stage.

they would have had 8 minutes to have made ATC aware of a control problem yet made no contact?

The aircraft flew in a straight line surely any pilot faced with such a situation would try everything to gain control which would make it extremely unlikely that the aircraft would fly a straight line.

Every indication points to the pilots being incapacitated and the autopilot holding the aircraft on a heading and nothing to two alert pilots trying to control or regain control of an aircraft

[dicks-airbus]

Germanwings crash: Evidence points to mechanical failure, say experts | News | Travel Trade Gazette

I fail to see any "evidence" here. Another BS article.

The aircraft flew in a straight line surely any pilot faced with such a situation would try everything to gain control which would make it extremely unlikely that the aircraft would fly a straight line.

Either they were incapacitated or unable to stop the decent due to mechanics. Both options point to a mechanical failure. As soon as the FDR is found and read we may know more.

[NigelOnDraft]

Assuming these things can be manually overridden, and accepting nothing is infallible, I've seen no explanation yet as to why it wouldn't be better for the aircraft to halt it's descent and possibly climb if it thinks it's about to fly into terrain

So long as you did not want to fly into Italy recently, where a spurious 8000' mountain appeared on the database for a while

Technologies are at various stages of development and maturity. You are trying to elevate airliners to the "Terrain Following Radar" of mil jets... IMO (E)GPWS is great for safety, but it is not yet robust enough to override a pilot.

[aterpster]

Founder:

Could those systems be in place in those aircrafts because TUC (Time of Useful Consciousness) is so short at the altitudes where those aircraft operate?

Indeed so. Of course one pilot is supposed to be on O2 at those altitudes, but we know how that one goes.

The other reason, I suspect, is the Payne Stewart (sp?) accident at the beginning of the century.

[STBYRUD]

Thats a rule for non-quick donning masks... Still exists.

[busTRE]

Tigger too

The point is that you need pressure oxy to sustain activity below 80mps. For shortish periods you can easily work efficiently above 10000 cabin alt. I have personally experienced 15000 in air tests with no obvious impact (not at controls I hasten to add). Thus it is safe to allow crew to operate to 45000 without pressure breathing equipment since they would experience the relatively small shortfall for only seconds as they started descent. Concorde at 65000 was a different matter and had full pressure sets and mandatory baro cell/pressure breathing training for the pilots.

[Lonewolf_50]

Germanwings crash: Evidence points to mechanical failure, say experts | News | Travel Trade Gazette

What evidence is she referring to? Unless this person has access to flight recorder data and the crash site, I find this analysis premature at best ... at first blush it borders on irresponsible and unprofessional given her position.

Hunter58:

IMHO those doors have, whether aplicable in this case or not, endangered more
lives than saved.

That might be a topic worthy of a second thread. Some might be interested in how you came to that conclusion.

[Eboy]

ACARS?

Perhaps ACARS reported abnormal equipment events.

[abdunbar]

Btw, have we ever heard from BEA what happened to Air Asia A320?

They were part of the investigation (though not in the lead). But how can it happen that 3 months after that accident we do not know about the cause WITH all recorders orderly retrieved.

What can we expect from BEA this afternoon and in this case?

The further away in time from an event the dynamics change;

the public forgets and isn't as interested or at least the press doesn't think so and for that reason the old incident is not on the front burner with the press.

next there are many interest groups with joint and opposing interests who will lobby government bodies and try to control the narrative and news releases in their favor. These interest groups are company, manufacture, regulators, politicians, employees and employee unions. Probably others also and they all have lawyers.

Now if there is some profound discovery early on in an investigation, a discovery that points to likely further and imminent occurence of similar failures, then you will see regulative action right away. As that has not occurred in the Latest Malaysia case then it would be fair to assume that nothing profound or unusual that has not been dealt with by previous rules and notices has been found. Now is the time for the lawyers and politicians to maneuver and determine whose ox will be gored.

[Aldente]

Germanwings crash: Evidence points to mechanical failure, say experts | News | Travel Trade Gazette

"This, she said, indicated that the crew were struggling to control the pitch of the aircraft “due to a servo actuator or hydraulic failure” and was therefore unable to fly high enough to clear the mountains"

However, the theory does not explain why no distress call was made during the eight-minute descent .

Quite so......

[busTRE]

To those calling for auto terrain avoidance.

In the past 5 years my Airbus has 'thought' it was going to hit some granite on 3 occasions including while holding over London. If it had taken it upon itself to carry out the avoidance maneuvre on each occasion there is a significant chance I would not be here now.

More automation isn't always the answer.

[Vilters]

Crash field

Some questions are posted about the crash site.

Car crashes are performed at 60 km/u, and see what remains of these steel cages.

Some time ago an institute did a car crash test at 120 km/u. The nominal max speed in Western Europe. => those results where eye openers.

Now you have an alumunum thin walled tube, smashing in a rock at a multiple of those car crash speeds.

Technical failure preventing pitch control as stated abvove?
Does that reporter even ""know"" how many ways there are to control pitch?

Windscreen crack or blowout "IS" a possibility.
With a 450 kt , -40°C windchill, storming into the cockpit?

After the initial shock, (averaging 5-10 seconds for a normal human in a relaxed state) , remember, you are just leveling off, checks done, starting to relax as this is supposed to be the "easy part".

After the intial BANG, the first pilot/human reaction is life preservation.
And it takes seconds to analyse, think, act - react.
+ Certainly shock of seeing a wounded pilot/copilot next to you.

Deathening noise, shearing -40°wind, "Where is my mask". be sure it will be NOTHING like in a simm, hell, I have to get lower.

Damm, start desend . . no time
it's over in seconds..

[Flaperon75]

12 seconds of useful consciousness....

...that's what you have at 38,000ft.... 12 seconds of useful consciousness.... not long!

Imagine a scenario where, say, the windscreen goes. All of the paperwork in the flight deck gets thrown into the air, several kilos of dust from every surface in the flight deck is sucked into the air also, visibility reduces. You've got 400 kts of headwind in your face. The loud roar this produces makes communication impossible. Your ears are agony. Any trapped air inside your body is agony. Maybe you've been hit by parts of windscreen blown into the flight deck and you're injured.

With this as the backdrop you have to fumble for your oxygen mask and get it on. A a previous post said..

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.

So you've donned your mask, maybe it's not set to 'emergency' setting. You cary out the initial items of the emergency descent drill which include 'pull altitude knob and turn' (set to FL70?) Remember at this stage you are not checking the value you have set it to. At a later stage in the drill you are to return to the alt knob and set FL100 or MSA (whichever higher) but before you can get to this stage your 12 seconds are up. So the aircraft continues in a controlled, thrust idle, descent, with 2 unconscious crew in the flight deck and FL70 set in the window.

At FL70 (6800 feet) the aircraft levels off and you are now below the level of the terrain. We know what happens next.

[Bleve]

Originally posted by lapp:
I have read the references and relates postings and must say that what you say is correct. Notwithstanding, it is my totally personal opinion, that setting "EMER"for mask breathing at FL 380 can't do nothing but help breathing. Would you elaborate on the possible negative consequences of doing that.

Have a careful read of my post at 25th Mar 2015, 05:10 (currently # 438) that describes exactly how a diluter/demand system works. It doesn't matter if the Demand setting is in Normal or Emergency, when you inhale you will get exactly the same pressure of gas. The only difference is when you are NOT inhaling - in Normal no gas will flow, in Emergency gas will flow (to keep the mask clear of smoke or fumes). So you are sort of half correct and fully half wrong. You are wrong by saying 'nothing but help breathing' because it provides no additional benefit - when you are breathing in you get the same amount of gas regardless of the Normal/Emergency setting. You are nearly half correct by asking about 'possible negative consequences': in a smoke/fumes incident there are none, but in a 'simple' depressurisation event the possible negative consequence is that you are unnecessarily wasting oxygen.

Are you freespeed2 posting under a different name?

[Founder]

PRESS CONFERENCE at 16:00

According to Swedish Media the French Accident Investigators will have a press-conference at 16:00 Central European Time... in less than an hour from now...

[Shaggy Sheep Driver]

Concorde at 65000 was a different matter and had full pressure sets and mandatory baro cell/pressure breathing training for the pilots.

Concorde never flew above 60,000' with pax on, a rule imposed because of what would happen in the case of a depressurisation event.

[areobat]

Decompression has been ruled out by GermanWings. This leaves me completely clueless.

ACARS sat data? I believe that cabin altitude is a transmitted parameter. If this stayed WNL for the last segment of the flight, then decompression could be ruled out.

[Pontius Navigator]

Explosive decompression is a near instantaneous as you will get. As suggested, on a large aircraft you would not expect explosive decompression from loss of cabin Windows etc.

Loss of cabin pressurisation could be a slower event but one presumes loss of pressure warnings would give time to react.

Between these is rapid decompression. Now there was speculation of loss of a windscreen. In the case of, poof its gone, you would have an explosive decompression. But more likely might be a rapid failure.

Say one layer cracking, then detaching, then intermediate and final layers failing in turn. At that point you might reduce cabin pressure and reduce pressure differential. The rate of failure may then increase leading to explosive decompression.

I am not suggesting this as a cause but suggesting that there are slower ways for decompression to occur.

[highflyer40]

As to the wreckage. Just look at how much was left of the aircraft that hit the twin towers, tiny pieces is about all, and that was hitting a building, granite is much stronger