Commencing an emergency descent by rolling into a 30 degree banked turn and pitching down at the same time is a common method used by many airlines. It not only prevents any negative G - keeps the passengers in their seats and turns the aircraft off the airway, thereby reducing the chance of a collision.
With no structual damage descent is made at MMO, with throttles closed and full speed brake. If damage is suspected a low speed option is available reducing to gear extension speed and lowering the undercarriage, also with throttles closed and full speed brake.
In either configuration descent rates remain about the same.
Prior to commencing the above the flight deck crew will have donned their full face oxygen masks and established crew communication and as the cabin altitude climbs above 10,000ft pax oxygen masks will have deployed in the cabin.
It is a straight forward exercise which is carried out regularly in the simulator.
