I have never seen so much lurid speculation, and use of "media reports", to try to come to a conclusion about this collision, in a long time.
The news media, report news, in a manner that sells their paper or website .. the accuracy of their reports is on the bottom of the list of their requirements .. and at the top,is the use of lurid wording, and extreme speculation, without any basis in fact-finding or accurate research ..
Re the "black boxes" .. or flight data recorders, and cockpit voice recorders .. as they should be more precisely termed ..
They are designed to withstand virtually all aspects of potential destruction in even the worst type of severe crash .. and since tape devices have given way to solid state devices, the info is even more recoverable ..
A pic of a dented outer casing, is enough to send the media into a feeding frenzy of speculation, that the "black boxes" are damaged to the point of not yielding adequate info .. when the pic shows a "black box" in relatively pristine condition.
They are designed to withstand salt water for 30 days .. extreme pressures .. and extreme temperatures .. that are beyond the maximum found in any known aircraft crash.
Definitive description of FDR's and CVR's .. note the CSMU design parameters!!! ..
http://travel.howstuffworks.com/black-box6.htm
The recovery of the info from these recorders will reveal everything that is needed to come to a satisfactory conclusion of the collision causes .. but it is a painstaking process that takes months.
I will however, hazard, a moderately-educated guess, at this point, on the collision causes .. remembering that all those involved, are/were professionals .. and we owe it to them, the recognition that they carried out their jobs with commensurate skill ..
1. It is highly likely, that a simple, faulty wiring connection, or installation, caused the transponder to fail intermittently. Despite testing, intermittent electrical faults are always likely to appear, even in new equipment ..
They are the most difficult to find .. and that which causes the greatest fury amongst electricians .. are intermittent faults - usually associated with connectors.
I am not aware of any back-up systems in transponder wiring.
2. The incorrect flight level may have been due to an intermittent radio fault, associated with the transponder wiring. This would lead to missed communications, and failure to adjust FL's accordingly.
3. There is little doubt that contact between the aircraft took place, and that pilots of both planes sighted each other, and took evasive action at the last few seconds.
At a closing speed of 240 m/sec, even in clear conditions, you don't have a lot of decision time up your sleeve .. by the time you sight a shape headed your way .. put the brain in gear .. weigh up evasive action (up, down, or bank?) .. and action that evasive move ..
That shape, headed your way, increases in size and closeness, at an astonishing rate .. when the closing speed is supersonic speed.
4. It appears that both pilots banked, causing wing to wing contact .. and the critical point, is just what was hit on the 737-800, to make it spiral out of control and break up in mid air .. as the wreckage pics clearly indicate.
As previously pointed out, even a small portion of winglet can cause enormous destruction to a critical control component, due to the impact speed.
It's not unlikely that any one of a dozen wing components was damaged enough, to render control impossible .. and once that point is passed, we all know the inevitable result.
I would suggest that all of these pilots are/were professionals, and carried out their duties in that manner .. but a sequence of minor mechanical failures compounded to create damage that resulted in a horrendous result.
Such are the frailties of our human-based engineering .. that we can build many fail-safe devices .. but minor errors can still creep in .. compound .. and result in major disaster.