A B737-800 flight crew experienced a pressurization problem and returned to department airport.

Attributes
ACN	802932
Time
Date	200808
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zzz.tracon
State Reference	US
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	B737-600 -700 -800
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	802932
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	802926
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : cabin alt ind other flight crewa other flight crewb
Resolutory Action	flight crew : landed as precaution other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During departure phase from ZZZ; we realized the aircraft was not pressurizing on the normal schedule. Requested leveloff at 10000 ft to evaluate system. Aircraft pressurization seemed to be catching up and leveled at approximately 6500 ft cabin altitude. We asked for a block altitude 10000-12000 ft which ATC granted. Cabin pressure continued to climb with aircraft. We descended back to 10000 ft and requested hold at ZZZ. After consulting QRH; we elected to return to ZZZ after reaching maximum landing weight. Due to the time of night; VMC WX; and light traffic; ATC was very helpful and expedited our return. This event was caught early as part of climb checklist and never reached a critical stage.

Original NASA ASRS Text

Title: A B737-800 FLT CREW EXPERIENCED A PRESSURIZATION PROBLEM AND RETURNED TO DEPT ARPT.

Narrative: DURING DEP PHASE FROM ZZZ; WE REALIZED THE ACFT WAS NOT PRESSURIZING ON THE NORMAL SCHEDULE. REQUESTED LEVELOFF AT 10000 FT TO EVALUATE SYS. ACFT PRESSURIZATION SEEMED TO BE CATCHING UP AND LEVELED AT APPROX 6500 FT CABIN ALT. WE ASKED FOR A BLOCK ALT 10000-12000 FT WHICH ATC GRANTED. CABIN PRESSURE CONTINUED TO CLB WITH ACFT. WE DSNDED BACK TO 10000 FT AND REQUESTED HOLD AT ZZZ. AFTER CONSULTING QRH; WE ELECTED TO RETURN TO ZZZ AFTER REACHING MAX LNDG WT. DUE TO THE TIME OF NIGHT; VMC WX; AND LIGHT TFC; ATC WAS VERY HELPFUL AND EXPEDITED OUR RETURN. THIS EVENT WAS CAUGHT EARLY AS PART OF CLB CHKLIST AND NEVER REACHED A CRITICAL STAGE.

Data retrieved from NASA's ASRS site as of May 2009 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.