A B737-300 on taxi in to gate the first officer noted cabin pressure at 4 psi. Switched to standby a...

Attributes
ACN	638773
Time
Date	200412
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : den.airport
State Reference	CO
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 180 flight time total : 5200 flight time type : 470
ASRS Report	638773
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : cabin pressure indication other flight crewa other flight crewb
Resolutory Action	flight crew : overrode automation flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

On taxi in from landing on runway 35L, after taxi-in flows were accomplished, the cabin began to pressurize. I noted the flight/ground switch was in ground position and the field elevation set to 5430 ft. However, the outflow valve was fully closed. The cabin pressure was approximately 4 psi differential and climbing at 2000 FPM. I switched the pressurization panel to 'standby' with no change in outflow valve position. I then switched to manual AC and was able to move the outflow valve to full open and the cabin depressurized. After shutdown, I contacted maintenance by radio, explained this problem and asked for a mechanic to meet the aircraft. I also wrote up a description of this problem in ACARS and submitted it. I met with the mechanic sent by maintenance, then left the cockpit to make room for the next crew. I also explained the problem to the outbound first officer. It appears the ACARS write-up was not received by maintenance. Callback conversation with reporter revealed the following information: the first officer advised maintenance of the problem and the outbound crew was also briefed. The reporter is unsure of the maintenance action but is certain the control panel was correctly programmed.

Original NASA ASRS Text

Title: A B737-300 ON TAXI IN TO GATE THE FO NOTED CABIN PRESSURE AT 4 PSI. SWITCHED TO STANDBY AND CABIN DIFFERENTIAL PRESSURE INCREASED AT 2000 FPM. SWITCHED TO MANUAL TO OPEN OUTFLOW VALVE.

Narrative: ON TAXI IN FROM LNDG ON RWY 35L, AFTER TAXI-IN FLOWS WERE ACCOMPLISHED, THE CABIN BEGAN TO PRESSURIZE. I NOTED THE FLT/GND SWITCH WAS IN GND POS AND THE FIELD ELEVATION SET TO 5430 FT. HOWEVER, THE OUTFLOW VALVE WAS FULLY CLOSED. THE CABIN PRESSURE WAS APPROX 4 PSI DIFFERENTIAL AND CLBING AT 2000 FPM. I SWITCHED THE PRESSURIZATION PANEL TO 'STANDBY' WITH NO CHANGE IN OUTFLOW VALVE POS. I THEN SWITCHED TO MANUAL AC AND WAS ABLE TO MOVE THE OUTFLOW VALVE TO FULL OPEN AND THE CABIN DEPRESSURIZED. AFTER SHUTDOWN, I CONTACTED MAINT BY RADIO, EXPLAINED THIS PROB AND ASKED FOR A MECH TO MEET THE ACFT. I ALSO WROTE UP A DESCRIPTION OF THIS PROB IN ACARS AND SUBMITTED IT. I MET WITH THE MECH SENT BY MAINT, THEN LEFT THE COCKPIT TO MAKE ROOM FOR THE NEXT CREW. I ALSO EXPLAINED THE PROB TO THE OUTBOUND FO. IT APPEARS THE ACARS WRITE-UP WAS NOT RECEIVED BY MAINT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FO ADVISED MAINT OF THE PROB AND THE OUTBOUND CREW WAS ALSO BRIEFED. THE RPTR IS UNSURE OF THE MAINT ACTION BUT IS CERTAIN THE CTL PANEL WAS CORRECTLY PROGRAMMED.

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.

A B737-300 on taxi in to gate the first officer noted cabin pressure at 4 psi. Switched to standby and cabin differential pressure increased at 2000 FPM. Switched to manual to open outflow valve.