GermanWings a320

[United744]

This post is full of speculation, but based on facts where possible.

Rate of descent: as Hardy rightly points out, it looks good for a VMO descent.

Smoke in cockpit: Whilst I question the debilitating effects if oxygen masks are donned as soon as smoke is seen/odd smell encountered, the fact the aircraft started a descent suggests this was already done (#1: masks, #2: get the aircraft descending). Was there a problem with the oxygen system?

Aircraft forward speed: FR24 uses ADS-B data, which reports ground speed. Accounting for altitude and winds aloft, and working the figures backwards, the aircraft doesn't appear to exceed VMO at any point. It also doesn't appear to get any slower than 300 kts at any point.

No communication of problem: This is where my thoughts will remain private. It seems very strange that nothing was said/transponder set accordingly.

Aircraft remained on flight plan route: Combined with the above, this is where things start getting very weird. They were descending towards mountains, whilst the sea and an alternate field for emergency landing were *behind* them and easily reachable. A 180 deg. turn would have put them nicely over the sea. Why wasn't any turn away from mountainous terrain ahead initiated?

Reports it flew level before crashing: Let's assume this was true...why such a low altitude as 6000 ft? MSA for the crash site was 7300 ft, and increasing to 14200 ft for the route. Even rushing the altitude selection - 12000 or even 14000 ft would work, even if totally depressurized. You won't pass out (10000 ft isn't some magic altitude).

CVR looks OK - the dome part is intact, and that is the part that matters. My confidence in BEA is low.

[falconeye]

In the actual press conference they said they could read the data from the VDR. They have the complete audio file and at the beginning everything is normal.

[United744]

Well this got very interesting...

National news here in the UK tonight reported that the investigators have out-ruled explosion, or loss of cabin pressure.

Can anyone else corroborate this???

[United744]

http://www.theguardian.com/world/2015/mar/25/recordings-voices-alarms-extracted-cockpit-crashed-germanwings-flight-4u9525

However, he said the information investigators had put together suggested the plane had not exploded and did not suffer a "classic decompression situation".

http://www.nytimes.com/2015/03/26/world/europe/germanwings-airbus-crash.html?_r=0

The senior French official, who spoke on the condition of anonymity because the investigation was continuing, said that the lack of communication from the pilots during the plane's descent was disturbing, and that the possibility that their silence was deliberate could not be ruled out.

Wow.  :shock:

[Hardy Heinlin]

"possibility that their silence was deliberate"

Typical yellow press nonsense. With the "inability to exclude every possibility" trick the journalist can mention whatever he or she likes. On the press conference one just needs to ask the question "Can you exclude that the ...?" -- "At the moment, we can't exclude that the ..."

[United744]

Whilst that is true 99% of the time, why would the investigators rule out so early the top 2 reasons for the aircraft departing cruise altitude suddenly and with no communication?

They said "it flew to the end", meaning it was in full control via (insert method here) from their perspective.

Even if they're talking to the press, they're usually much more guarded than this if they aren't sure.  :?

[GodAtum]

A member of FS2Crew died on that flight

[John H Watson]

In a smoke in the cockpit scenario, with no vision available, I could imagine the aircrew being able to find the alt sel knob and dial in a lower altitude  (of unknown magnitude), but not be able to dial in the correct ATC distress code. Dialing in a distress frequency on VHF might be impossible (unless already in the standby window), but that wouldn't stop you simply sending a distress message on the current frequency.

I assume the A320 is fitted with EGPWS, in which case, they should have received sufficient warning time to avoid terrain (but if you can't see, how can you dial in a safe altitude?).

Other theories included a cracked windshield, but this doesn't seem to fit the facts. The crew would still be able to make emergency calls (since the airplane appeared to be under control).

There was also a previous A320 safety report about a false cabin altitude warning. The crew made a descent despite the cabin pressure showing normal values.

[HercMighty]

Being reported now that by the voice recorder a pilot was locked out of the cabin.

Speculation currently is bathroom break followed by a medical emergency with the remaining pilot. Thought that if the "joystick" was bumped the plane could have been put into a descent.

Don't know enough about the Airbus to speculate myself....

[Phil Bunch]

On pprune, this link was posted, allegedly being the V/S data for the flight.

http://www.zerohedge.com/sites/default/files/images/user5/imageroot/2015/03/rapid%20descent.jpg

 Is it possible that *anyone* outside of the real accident investigation team would have access to such data?  I would think that the airline and any other participants would lock up their records and data with strict security after a crash.

[Will]

The New York Times is reporting that one pilot left the cockpit and then tried to re-enter, pounding louder and louder on the door, unable to get back in:

Begin quote:

A senior military official involved in the investigation described "very smooth, very cool" conversation between the pilots during the early part of the flight from Barcelona to Düsseldorf. Then the audio indicated that one of the pilots left the cockpit and could not re-enter.

"The guy outside is knocking lightly on the door and there is no answer," the investigator said. "And then he hits the door stronger and no answer. There is never an answer."

He said, "You can hear he is trying to smash the door down."

"We don't know yet the reason why one of the guys went out," said the official, who requested anonymity because the investigation is continuing. "But what is sure is that at the very end of the flight, the other pilot is alone and does not open the door."

http://www.nytimes.com/2015/03/26/world/europe/germanwings-airbus-crash.html?_r=0

[falconeye]

This seems to be so unbelivable, but would explain everything.In this scenario the pilot must lock the door actively from inside. So it is impossible that he was unconscious at that moment. And what that means...

[frumpy]

On pprune, this link was posted, allegedly being the V/S data for the flight.

http://www.zerohedge.com/sites/default/files/images/user5/imageroot/2015/03/rapid%20descent.jpg

 Is it possible that *anyone* outside of the real accident investigation team would have access to such data?  I would think that the airline and any other participants would lock up their records and data with strict security after a crash.

The data looks like the ADS-B data from flightradar24.

Basically I'm thinking about two possibilies... a passed out pilot or suicide.

[IefCooreman]

Avoiding to speculate too much, some remarks on what I've read here that might help to avoid speculating certain cases:

With smoke your first action before descending would be to turn to your closest alternate "in time". Which never happened so the scenario is very unlikely. It is also very true that with an oxygen mask on your face, everything in front of you is reachable, however anything sideways/up/down requires your head to move since the mask destroys all peripheral view and "restrains" your head movement because of the hose connected it, especially if you want to look down. The center pedestal in between pilots is the most difficult to reach so changing VHF or squawk codes becomes annoying. However, in Europe your emergency call is on the active ATC frequency, not on 121.5. ATC usually then comes back with discrete frequency which is where the annoying stuff starts :-).

Concerning all remark on decompression: it is funny everybody thinks about rapid decompression, while I have always found the "slow" ones to be more challenging. You look at it happen and think: what do we do? Oxygen? Rapid descent to avoid oxygen use? There's a lot of looking, waiting and thinking going on. Rapid decompressions are a matter of procedures "ox on, check intercom, dive..."

EGPWS is indeed present although it isn't bullet proof, there is no performance calculation whatsoever. Especially not if you are targetting upslopes of 70% during an emergency descent.

The most strange thing in the real scenario is why there wasn't a leveloff close to 10000ft, the path of the aircraft doesn't seem to change a tiny bit. 10000ft altitude is just one of those magic values in aviation that makes a pilot "do" stuff. It didn't in this case apparently. So either the pilots weren't there or they were not conscious is as far as my speculation goes.

[Will]

So if the New York Times is correct (see my post above for the reference), then one pilot was locked out of the cockpit during the descent.

Not wanting to be too speculative, that does suggest a few scenarios, such as the remaining pilot being incapacitated by a medical condition. If he had a seizure or something, he might have flailed about, enough to disengage the autopilot and begin a descent, followed my medical unconsciousness. Or he could have been hand-flying with the autopilot off while the other pilot left the cockpit, and then coincidentally had a heart attack. In-flight heart attacks have happened in airliners on a number of occasions; it's conceivable that he was rendered unconscious while the autopilot was off and while the other pilot was locked out of the cockpit.

Those are improbable scenarios, perhaps, but then so is the whole idea of an airliner descending from cruise flight into a crash without any distress calls. So you have to think about improbable events...

[falconeye]

But the pilot who is inside the door must activate a switch at the door to block it for opening on the outside. As far as I know you normally can unlock it with an code. But it is not possible to open if it is blocked from the inside. The inner pilot normally has no reason to block it from inside. So the scenario that he had an heart attack or something is not very likely in my opinion.But I hope I am wrong.

[Will]

I don't know about Airbus aircraft... whether a pilot can get in with a key or a code, or whether a pilot has to be specifically granted access by someone in the cockpit.

[Jeroen Hoppenbrouwers]

I believe this is not Airbus or Boeing-specific, but a global standard rule.

Door is unlocked on the ground, locked in flight.
Crew can exit at any time.
Nobody can get in without:
1. Crew opening the door, OR
2a. Entering the entry code and waiting 30 seconds, UNLESS
2b. within those 30 seconds the crew denies access.

What I don't know is whether that access denial must be repeated every time the code is re-entered, or that this is a latched position on the cockpit door lock switch?


H

[Will]

Do you know what the rule is? I'm curious. Is it "fail secure," where nobody gets in without permission of the current cockpit occupant(s), or "credential secure," where someone with the correct password or key can enter no matter what?

I guess a third option would be "credential secure" with an optional manual override, where the current occupant(s) might decide to keep even authorized people out.

[Jeroen Hoppenbrouwers]

It seems both: you can get in UNLESS the flight crew actively denies you access (time after time). This seems the best of both worlds. The only flaw is that once inside, the bad guy/gal is in total control -- but I sort of agree that this seemed a good idea as the one up front is in total control.


H