An MD80 on passing 10000 ft crew noted a sudden change in cabin pressure. Diverted. No cabin pressur...

Attributes
ACN	669025
Time
Date	200508
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	669025
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : cabin altitude indicator other flight crewa other flight crewb
Resolutory Action	flight crew : diverted to another airport other
Supplementary
Problem Areas	Aircraft Chart Or Publication Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

We left the gate at XA31 and found out we had a company imposed delay of about 1 hour 15 mins. We took off from ZZZ at approximately XB45. All system worked normal; including cabin pressurization; until about 10000 ft. Our clearance was to 13000 ft and as we were passing 10000 ft we felt a sudden change in cabin pressure. We requested and were approved to level off and initially leveled at 11000 ft; the earliest we could level. Soon after that; when we realized the cabin pressure was not working; we descended to 10000 ft. We never got a 'cabin altitude' warning light. We did get a 'xfer lockout' light and a 'standby on' light. Besides the pressure bump; this was our only indication of a problem. That led us to look at the cabin altitude which indicated the cabin was not pressurized; with differential pressure almost zero and cabin altitude very high. The packs were working and all other switches were in the correct position. We complied with the checklist and tried to restore the normal controller with no success although the standby and xfer lockout lights did reset. We then tried to pressurize manually with no success. We never considered ourselves to be in a 'safety of flight' situation since the cabin never exceeded 10000 ft as indicated by no cabin altitude light and no altitude warning horn. We elected to return to ZZZ and did an overweight landing for reasons discussed below. During the process of working the problem; the flight attendants called a couple of times to inquire about the pressure bump that they also felt. A later call revealed that at least 1 of the flight attendants and at least 1 passenger had 'a tingly feeling' in their arm. I attributed this to the cabin altitude being higher than normal and elected to land slightly overweight (133400 pounds) in case of further complications. After arriving at the gate; it was decided to use a different aircraft and fly the leg to ZZZ1.

Original NASA ASRS Text

Title: AN MD80 ON PASSING 10000 FT CREW NOTED A SUDDEN CHANGE IN CABIN PRESSURE. DIVERTED. NO CABIN PRESSURE WARNING LIGHT OR HORN. BOTH PACK OPERATING NORMAL.

Narrative: WE LEFT THE GATE AT XA31 AND FOUND OUT WE HAD A COMPANY IMPOSED DELAY OF ABOUT 1 HR 15 MINS. WE TOOK OFF FROM ZZZ AT APPROX XB45. ALL SYS WORKED NORMAL; INCLUDING CABIN PRESSURIZATION; UNTIL ABOUT 10000 FT. OUR CLRNC WAS TO 13000 FT AND AS WE WERE PASSING 10000 FT WE FELT A SUDDEN CHANGE IN CABIN PRESSURE. WE REQUESTED AND WERE APPROVED TO LEVEL OFF AND INITIALLY LEVELED AT 11000 FT; THE EARLIEST WE COULD LEVEL. SOON AFTER THAT; WHEN WE REALIZED THE CABIN PRESSURE WAS NOT WORKING; WE DSNDED TO 10000 FT. WE NEVER GOT A 'CABIN ALT' WARNING LIGHT. WE DID GET A 'XFER LOCKOUT' LIGHT AND A 'STANDBY ON' LIGHT. BESIDES THE PRESSURE BUMP; THIS WAS OUR ONLY INDICATION OF A PROB. THAT LED US TO LOOK AT THE CABIN ALT WHICH INDICATED THE CABIN WAS NOT PRESSURIZED; WITH DIFFERENTIAL PRESSURE ALMOST ZERO AND CABIN ALT VERY HIGH. THE PACKS WERE WORKING AND ALL OTHER SWITCHES WERE IN THE CORRECT POS. WE COMPLIED WITH THE CHKLIST AND TRIED TO RESTORE THE NORMAL CTLR WITH NO SUCCESS ALTHOUGH THE STANDBY AND XFER LOCKOUT LIGHTS DID RESET. WE THEN TRIED TO PRESSURIZE MANUALLY WITH NO SUCCESS. WE NEVER CONSIDERED OURSELVES TO BE IN A 'SAFETY OF FLT' SIT SINCE THE CABIN NEVER EXCEEDED 10000 FT AS INDICATED BY NO CABIN ALT LIGHT AND NO ALT WARNING HORN. WE ELECTED TO RETURN TO ZZZ AND DID AN OVERWT LNDG FOR REASONS DISCUSSED BELOW. DURING THE PROCESS OF WORKING THE PROB; THE FLT ATTENDANTS CALLED A COUPLE OF TIMES TO INQUIRE ABOUT THE PRESSURE BUMP THAT THEY ALSO FELT. A LATER CALL REVEALED THAT AT LEAST 1 OF THE FLT ATTENDANTS AND AT LEAST 1 PAX HAD 'A TINGLY FEELING' IN THEIR ARM. I ATTRIBUTED THIS TO THE CABIN ALT BEING HIGHER THAN NORMAL AND ELECTED TO LAND SLIGHTLY OVERWT (133400 LBS) IN CASE OF FURTHER COMPLICATIONS. AFTER ARRIVING AT THE GATE; IT WAS DECIDED TO USE A DIFFERENT ACFT AND FLY THE LEG TO ZZZ1.

Data retrieved from NASA's ASRS site as of January 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.

An MD80 on passing 10000 ft crew noted a sudden change in cabin pressure. Diverted. No cabin pressure warning light or horn. Both pack operating normal.