The investigation unit last year revealed problems with engine number two of the twin turboprop Fairchild Metroliner which could have caused an uneven thrust from the wings.
This was mentioned early in this thread and, although I appreciate that there are now 1200 plus posts, I would humbly suggest that posters read them before posting supposedly new information.
To repeat some of that information, this type of aircraft is known to be tricky at low speeds and in addition it is likely that there was a thrust differential between the engines. It is also likely that the crew knew this. As Big Pistons Forever has stated, this does not change the essential facts of the accident.
The main reason that the final report is delayed is because of the difficulty in dealing with the paper-chase in Spain.