Bear in mind that it has been reported that witnesses saw a "bright flash" and around 6 or so falling chunks of burning debris.
Wrong, wrong, wrong and wrong!
The initial El Mundo report said how the "witnesses" saw a bright flash which dissipated after 6 seconds, not 6 distinct objects falling. What you are talking about was not only poor reporting by The Age but also, at least, a mistranslation.
Also, these "witnesses" on the Air Comet flight (the one the two people who claim to have seen this flash were on) were over 2000km away. Now, are you saying that human eyesight is able to not only see an aircraft at that distance but could also see individual parts falling, especially since the suggestion is that AF447 was actually in a rather large cloud at the time?