With regard to the "deep stall" idea here, if the PF applied ANU command all the way to the surface, why is it necessary to invoke a hypothetical (and unlikely) unrecoverable deep stall? Between the stabilizer trim setting and the up elevator, isn't that enough? In fact, when the PF did momentarily start to put the nose down, the airplane responded, but then the misbegotten stall warning went off and discouraged him from continuing. Has there ever been a proven instance of an unrecoverable deep stall in a conventionally-configured (ie low tail) transport?