What caused the Feb 12 2009 plane crash of flight 3407 into a house in Buffalo NY?

It is much too soon to ask this question. The National Transportation Safety Board has already started an investigation into this accident. Their investigations are extremely thorough; the time taken is not measured in hours or days, but in months. Many people, especially those who lost their nearest and dearest in this tragedy, are anxious to know what happened, and why, as soon as possible. However, the long-term national interest is not in a speedy answer, but in the correct one. Each time that a careful and thorough examination brings out the reason for the accident, it reduces the risks of a recurrence of that type of crash.