As Basil said ... 1. Situation 2. Crew response 3. A/C landed safely .. Perfect.
Statistics may play a part in this ... It is statistically unlikely to have a further issue with pressurisation or smoke/ fire in cockpit. In this case maybe portable oxygen/ Drager hoods could have sufficed as back up until a diversion could be effected at cruise levels, thereby minimising any proximity conflicts. For me Land As Soon As Possible is correct.
If a decision is made to operate outside (or, you have no choice) of your NAT procedural clearance then it is a MAYDAY call. Another scenario where this can happen is on the high latitude Canadian routes with a LOW FUEL TEMP warning, and either an acceleration or a descent is decided upon ... MAYDAY.
I. Duke
Last edited by Iron Duke; 26th Jul 2013 at 16:00.