I'll bow out for the moment (hurrah I hear you say), pointing out that contrary to some newspaper reports EASA themselves are yet to be convinced that 2 on the Flight Deck provides the guaranteed/only solution, and have concerns about introducing extra risks, and have therefore not yet at least made it mandatory:
From EASA Safety Information Bulletin 2015-04:
"The Agency recommends operators to re-assess the safety
and security risks associated with flight crew members
leaving the flight crew compartment due to operational or
physiological needs during non-critical phases of flight.
Based on this assessment, operators are recommended to
implement procedures requiring at least two persons
authorised in accordance with CAT.GEN.MPA.135 to be in
the flight crew compartment at all times, or other equivalent
mitigating measures to address risks identified by the
operator’s revised assessment.
Any additional risks stemming from the introduction of such
procedures or measures should be assessed and mitigated."
Last edited by wiggy; 10th Apr 2015 at 09:07.