Today (May 13th) there was an interview of Rémi Jouty, chief of BEA (French equivalent of NTSB) in the very serious French newspaper L'Usine Nouvelle (business related top ranked newspaper):
Vol MH370 disparu : pour le patron du BEA "il y a clairement eu une volonté de rendre l'appareil invisible" - Aéronautique - Défense
For him, it is beyond imagination that a simple mechanical incident might have lead to a disconnection of all communication means. He said there had been a clear will to make the aircraft invisible.