FLC OF ACR WDB ACFT FLC DEVIATED FROM ASSIGNED TRACK DUE TO A RAPID DSCNT FOR A CABIN PRESSURIZATION PROBLEM.

Narrative

A POSSIBLE COLLISION COURSE OCCURRED BECAUSE THE PF DID NOT FOLLOW INSTRUCTIONS FROM ATC; AND THE OTHER 2 PLTS WERE BUSY DISCUSSING AN EVENT THAT HAD JUST CAUSED THE ACFT TO MAKE A RAPID (NOT EMER) DSCNT FROM FL390 TO 10000 FT. I SUSPECT THE PF WAS PAYING ATTN TO THE DISCUSSION MORE THAN THE COURSE TO BE FLOWN. THE ACFT WAS ON VECTORS AT 41000 FT FOR DSCNT. PASSING THROUGH FL370; THE #2 ENG BLEED VALVE FAULTED WHILE FOLLOWING THE ECAM PROC; THE #1 ENG BLEED VALVE FAULTED. BOTH PACKS TRIPPED AND THE CABIN BEGAN TO RISE. REQUESTED DSCNT TO FL240 AND THEN TO 10000 FT WHEN IT BECAME APPARENT THAT WE WOULD NOT REGAIN CTL OF THE CABIN. CABIN ROSE TO 11800 FT. NO OXYGEN MASKS WERE DEPLOYED IN CABIN. AFTER FURTHER DSCNT TO 6000 FT ON 160 DEG HDG; WE WERE CLRED DIRECT TO DPK VOR. COPLT WAS FLYING AND CAPT WAS GOING OVER THE JUST PERFORMED RAPID DSCNT WITH THE RELIEF OFFICER WHEN THE CAPT NOTICED THAT WE WERE STILL ON A 160 DEG HDG. HE CALLED ATC AND STATED WE WERE STILL ON 160 DEG HDG AND ATC SAID TO GO DIRECT TO DPK. A FEW SECONDS LATER ATC SAID TO TURN QUICKLY L TO 90 DEGS AND DSND TO 5000 FT. NO OTHER ACFT WAS MENTIONED; BUT I SUSPECT A COLLISION COURSE WAS AVERTED BY THE TURN AND DSCNT. IT WAS A CASE OF ALL PLTS INVOLVED IN THE POST-DSCNT DISCUSSION AND NO ONE FLYING THE ACFT.