Use of EXP Expedite Descent button is prohibited by most operators due to the automatics inability to control the speed properly. This was quite an old bus, so probably had it fitted, but I'd be surprised if Germanwings allowed its use.
It's not really needed, as you can achieve a safe 5000fpm simply with open descent and very careful use of speedbrake. All this talk of 3500 fom being a hi speed dive is nonsense, certainly a smartish descent but the vs amber caution only come on around 5000fpm. Sorry can't remember the exact figure.

And no, the speed brakes do not automatically deploy, the aircraft protects itself from over speed with a gentle pitch up to recover the normal sped range.

An Australian journalist in London says that one of the school kids had lost/misplaced their passport and that at one point there was concern that they would not make the flight.

Potentially a cause of delay?

Yes it has but in a slow loss the descent action should be effective well before any crew performance issue arises.

There is no passport control flying between BCN and DUS.

The original Design Service Goal for the A320 was 60,000 flight hours and 48,000 cycles, but there are life extension programmes. I don't know if this particular aircraft has undergone the requirements for the "Extended Service Goal".

Some information can be found here.

Timing
 

Apologies if it has already been answered but why is there an apparent discrepancy in timings from the FR24 information and the timings that the media and Germanwings are saying was last contact?

FR24 had last contact at 09.41 yet Germanwings says it was 09.53?

Not really. Priorities in order:

1. Get on Oxygen
2. Establish comms between the 2 pilots, confirm who is flying.
3. That pilot states "Emergency Descent" and actions this via MCP (Autopilot selections)
4. This will involve essentially a random lower Altitude and Pull to start the descent, turn & Pull Hdg to turn according to SOP (varies), select an appropriate speed
5. Ensure Idle thrust (autothrust, or manually if required), and select speedbrake as required by type of descent
6. Now refine the Autopilot settings - sensible Altitude, Hdg, Speed etc.
7. Now call for drill and check what you have done from ECAM drill, or QRH
8. In that drill will come R/T, Squawk

Some airlines / types may alter things here slightly, some pilots may shift priorities. It is not rigid.

It should not be difficult to see that if the "get on Oxy" goes wrong, life is not looking good (and not saying that happened here). It is far more important than starting the descent.

In reference to reports of lost/misplaced passport this is a good point, but is photo ID required on this route? And passport used as ID?

Probably not relevant, but this airframe sustained a bit of flap damage back in 2002.

http://www.fss.aero/accident-reports...2-07-09-UK.pdf

International Spanish TV news are saying that one German student had forgotten their travel documents (could be either ID or passport), which were brought to Barcelona airport by the student accommodation providor and that allowed the student group to board the aircraft.

This was probably me misinterpreting the news: It seems the crews were debating whether they were fit to fly, not the aircraft. Lost in translation. My bad.

An explosive decompression would be more in line with a lower ROD as well as with the theory of the crew being unconscious until impact.

Pure speculation, but I would incline to the theory of an uncontained structural damage leading to sudden decompression and to the crew to initiate an emergency descent (with a lower rate due to the need to not increase speed) having made the initial procedures, but failing to fine tune them, due to having lost consciousness.

Thence the lack of communication with ATC...

Well, what did you expect, it s all DLH in Germany, except Air Berlin.

And TUI, Condor, Germania...

Different type of aircraft, of course, and an unlikely scenario, but what about the British Airways flight that had a windscreen failure, leading the pilot to be sucked halfway out of the aircraft? Rapid depressurization, a very cold and presumably very busy co-pilot, and everything blowing around the cockpit. In such an event, it would seem that the co-pilot's O2 mask could easily become damaged or dislodged.

So like a UK domestic flight? ID still needed which is likely to be a passport, national identity card or driving license.

In which case a pax with missing ID might be a problem, albeit solvable.

You need an ID or passport to enter the aircraft in Spain. You do not need it in Germany.

You can get past security and to the gate without ID everywhere in Europe, though, if your destination is in the Schengen area.

This combination makes it dangerous to miss your return flight just at the gate as one does not notice the missing ID on the flight ex Germany (happened to me in France and was resolved by my airline ID card after a lot of discussions only)

The (reported) total lack of communications from the crew for the entire duration of the descent is strongly suggestive of crew incapacitation.


It appears from what we know thus far that the crew have commanded the descent, and the average rate would appear to be consistent (I would imagine) with speed brakes out, or at least a speed of close to Mmo/Vmo.

I can only speak for the 737, and am led to believe A320 family is similar in the drills, so imagine (via the AFS) a random lower altitude would be initially set (just to start the descent ) with one of the follow up actions being to come back to it to set 10,000 or MSA (whichever higher) implying that, if you lost consciousness after commencing the descent, you may continue down to . . . . well, whatever altitude was set by default on the panel (could be as low as 0000)

I have heard reliable reports of a 737 flying around for a significant amount of time (lets say more than 1 day ) with the crew 02 turned off down at the bottle due to a maintenance error. It appears that the 02 expended during the mandated crew 02 tests done during this period, was not significant compared to what was left in the line between bottle/mask.

God knows how the crew(s) who flew it 2 ? 4 ? or however many sectors for however many days must have felt when they heard they operated it, with but a few seconds worth, of 02 available in the lines . . . personally, I think I would feel quite sick.

Very short odds indeed for an aircraft with a similar maintenance whoopsy to coincidentally have a decompression requiring the use of crew 02, but, that's what Murphy is for. . . . . . .

EMER DESC (31 March 2013)
 

Nigel ,the double loop is meant to refine the original fcu selections once the aircraft is descending. The RoD achieved is half that quoted in the FCTM