Narrative:

I was piloting a citation 500 with no passenger en route to a delivery in wisconsin. Approximately 40 mi northeast of uvalde, tx, at 27000 ft I had a partial rupture in the door seal of my aircraft which caused a slow climb to begin in cabin altitude. I immediately began breathing supplemental oxygen and informed ATC of my problem. I told the controller I needed to return to uvalde and begin an immediate descent. The controller told me to turn right direct uvalde and begin a descent. I do not remember being assigned any new altitude. The controller also informed a military C5 who was climbing behind me of my problem and I think assigned him a new heading. In my turn I spotted the C5 and believed no conflict existed. The controller asked if I could maintain my present altitude at about 23500 ft and I told him probably since I still had a livable cabin altitude but that I really needed to descend further. At that point I was told for what I think was the first time my assigned altitude was 25000 ft and he offered lower if I wanted to declare an emergency. I felt that no emergency existed yet and told him I was clear of the C5. Before the handoff the controller gave me a number to call the supervisor on duty for rock springs (ZHU). I called after landing. I feel the contributing factors were 1) the urgency of the pressurization problem, 2) a miscom of assigned altitude, 3) my reluctance to declare an emergency, and 4) ATC's reluctance to declare an emergency for me.

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Original NASA ASRS Text

Title: A CITATION 500 IS REVERSED IN COURSE AND CLRED TO 'DSND' WHEN THE PLT EXPERIENCES A SLOW LOSS OF CABIN PRESSURE. DURING DSCNT THE CITATION COMES IN CLOSE PROX TO A CLBING C5, ALMOST LOSING SEPARATION 40 MI NE OF UVA, TX.

Narrative: I WAS PILOTING A CITATION 500 WITH NO PAX ENRTE TO A DELIVERY IN WISCONSIN. APPROX 40 MI NE OF UVALDE, TX, AT 27000 FT I HAD A PARTIAL RUPTURE IN THE DOOR SEAL OF MY ACFT WHICH CAUSED A SLOW CLB TO BEGIN IN CABIN ALT. I IMMEDIATELY BEGAN BREATHING SUPPLEMENTAL OXYGEN AND INFORMED ATC OF MY PROB. I TOLD THE CTLR I NEEDED TO RETURN TO UVALDE AND BEGIN AN IMMEDIATE DSCNT. THE CTLR TOLD ME TO TURN R DIRECT UVALDE AND BEGIN A DSCNT. I DO NOT REMEMBER BEING ASSIGNED ANY NEW ALT. THE CTLR ALSO INFORMED A MIL C5 WHO WAS CLBING BEHIND ME OF MY PROB AND I THINK ASSIGNED HIM A NEW HDG. IN MY TURN I SPOTTED THE C5 AND BELIEVED NO CONFLICT EXISTED. THE CTLR ASKED IF I COULD MAINTAIN MY PRESENT ALT AT ABOUT 23500 FT AND I TOLD HIM PROBABLY SINCE I STILL HAD A LIVABLE CABIN ALT BUT THAT I REALLY NEEDED TO DSND FURTHER. AT THAT POINT I WAS TOLD FOR WHAT I THINK WAS THE FIRST TIME MY ASSIGNED ALT WAS 25000 FT AND HE OFFERED LOWER IF I WANTED TO DECLARE AN EMER. I FELT THAT NO EMER EXISTED YET AND TOLD HIM I WAS CLR OF THE C5. BEFORE THE HDOF THE CTLR GAVE ME A NUMBER TO CALL THE SUPVR ON DUTY FOR ROCK SPRINGS (ZHU). I CALLED AFTER LNDG. I FEEL THE CONTRIBUTING FACTORS WERE 1) THE URGENCY OF THE PRESSURIZATION PROB, 2) A MISCOM OF ASSIGNED ALT, 3) MY RELUCTANCE TO DECLARE AN EMER, AND 4) ATC'S RELUCTANCE TO DECLARE AN EMER FOR ME.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.