Narrative:

While on functional flight test following heavy 'C' maintenance, immediately following the maximum differential pressurization check, the cabin pressure relief valves would not reset. An immediate descent to 10000 ft was made and returned directly to tul for landing. Postflt inspection revealed foreign object damage blocking relief valves.

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Original NASA ASRS Text

Title: AN ACR FLC ON A POST MAJOR MAINT TEST FLT FIND THAT THEY WERE UNABLE TO REGAIN CTL OF THE OUTFLOW VALVE FOR THE PRESSURIZATION SYS AND THEY HAVE TO PERFORM AN EMER DSCNT AND RETURN TO TUL.

Narrative: WHILE ON FUNCTIONAL FLT TEST FOLLOWING HVY 'C' MAINT, IMMEDIATELY FOLLOWING THE MAX DIFFERENTIAL PRESSURIZATION CHK, THE CABIN PRESSURE RELIEF VALVES WOULD NOT RESET. AN IMMEDIATE DSCNT TO 10000 FT WAS MADE AND RETURNED DIRECTLY TO TUL FOR LNDG. POSTFLT INSPECTION REVEALED FOREIGN OBJECT DAMAGE BLOCKING RELIEF VALVES.

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.