B757 ACFT IN HIGH SPD DSCNT STARTED LOSING CABIN PRESSURE. FLC ATTEMPTED TO CTL IT TO NO AVAIL. THE DISTR RESULTED IN DSCNT BELOW ASSIGNED ALT. ACFT CHKED BY MECHS AND NO KNOWN CAUSE FOUND.

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ON A CLASSIC HIGH SPD DSCNT EXECUTING THE SLS ONE ARR. DSNDING TO 2000 FT BY SIGAS; ACFT BEGAN TO LOSE CABIN PRESSURE AT RATES OF 2000-3000 FT. THIS WAS PRECEDED BY LOUD AIR NOISE IN THE COCKPIT. NO EICAS MESSAGE OR AURAL WARNINGS; SWITCHED TO MODE 2 WITH NO EFFECT. THEN WENT TO MANUAL WITH NO EFFECT. I WAS HAND FLYING AND BECOMING PREOCCUPIED WITH THE PROB. FLY THE AIRPLANE STUPID. I SETTLED APPROX 100 FT BELOW 2000 FT. ALSO MISSED THE TRANSITION ALT OF 4000 FT; RESET AT 29.77. NOW ALMOST 300 FT LOW. CORRECTED IMMEDIATELY...STILL CONFUSED AT PROB...DECIDED THAT NO THREAT EXISTED OTHER THAN DISCOMFORT AND EARS POPPING. PRESSED ON AND LANDED WITHOUT ANY FURTHER ATTEMPT AT A CORRECTION. ON GND FLT ATTENDANTS SAID A LOT OF AIR NOISE AND CURTAINS WAVING. NO COMPLAINTS FROM PAX. WROTE UP IN LOG. MECHS COULD NOT DUPLICATE. ACFT WENT TO DFW AND WAS TRACKED; NO PROB. I FIGURE THE AIR/GND LOGIC CHANGE CURED THE PROB FOR NOW. COULD NOT UNDERSTAND THE PROB WITH NO EICAS. I DO NOT BELIEVE IT WAS AIRFRAME. EITHER FAULT WITH OUTFLOW OR EE COOLING. MORAL TO STORY: CAPT DESIGNATES WHO WILL WORK THE PROB AND WHO WILL FLY THE ACFT. SEEMS I'VE HEARD THAT SOMEWHERE BEFORE; ABOUT 500 TIMES.