LOSS OF PRESSURIZATION RESULTS IN EMERGENCY DESCENT COINCIDENT WITH AN ATC FREQ CHANGE.

Narrative

WHILE DSNDING TO FL240; ACFT'S DOOR SEAL DEFLATED; CAUSING A LOSS OF PRESSURIZATION IN ACFT. THIS EVENT HAPPENED DURING A HDOF FROM ZZZ1 CTR TO ZZZ CTR. LAST XMISSION TO ZZZ1 CTR WAS SOMETHING TO THE EFFECT OF HAVING LOST PRESSURIZATION; AND ACFT WAS DSNDING TO 14000 FT. UPON CHKING IN WITH ZZZ CTR; WE RPTED THAT WE WERE IN A DSCNT FROM FL240 TO 14000 FT DUE TO A LOSS OF PRESSURIZATION. DURING DSCNT; PASSING THROUGH APPROX FL190; DOOR SEAL RE-INFLATED; CAUSING A RAPID INCREASE IN ACFT PRESSURIZATION. SECONDS LATER; DOOR SEAL DEFLATED A SECOND TIME; AND ATC CLRED US DOWN TO 14000 FT. GIVEN THAT I (THE CAPT) WAS ON OXYGEN; AND MY FO WAS ON HIS SECOND TRIP IN THE ACFT; MY ATTN WAS ON GETTING THE ACFT SAFELY OUT OF ALT. I DECIDED TO EXERCISE MY AUTH UNDER 91.3 TO DEVIATE FROM THE PREVIOUSLY ASSIGNED ALT OF FL240. AT SOME POINT; THE ZZZ CTLR ADVISED THAT THERE WAS A 'POSSIBLE PLTDEV' AND INSTRUCTED US TO CALL THE CTR. I AM UNSURE OF WHAT CAUSED THE DOOR SEAL TO DEFLATE; AND ASIDE FROM NOT MAKING IT CLR TO THE CTLR I WAS IN AN EMER SITUATION; I DID NOT FEEL THAT I HAD THE TIME TO CLARIFY AT THE MOMENT; AS I WAS EFFECTIVELY A SINGLE PLT AT THAT POINT GIVEN MY FO'S LACK OF EXPERIENCE IN THE ACFT. UPON TALKING WITH MY DIRECTOR OF OPS; I AGAIN EXPRESSED MY DISPLEASURE WITH HAVING SUCH AN INEXPERIENCED FO AND SUGGESTED THAT WE DISCONTINUE THE USE OF UTILIZING CREW MEMBERS WHO ARE QUALIFIED IN ANOTHER MAKE AND MODEL OF JET AS AN FO IN ANOTHER JET. I UNDERSTAND THE NEED TO ADVISE ATC OF THE SITUATION; AND THOUGHT I HAD MADE MY INTENTIONS CLR; BUT DO NOT RECALL ACTUALLY DECLARING THE EMER. GIVEN THE SITUATION; I FELT IT BETTER TO FLY THE ACFT; AND COMMUNICATE WHEN THE WORKLOAD PERMITTED.