Narrative:

After level off at FL300; just established at cruise; my first officer noticed that the cabin pressure was climbing slowly through 8;500 ft. We temporary descended to FL280 to see if would stop or go down and pulled up the ecs page; everything appeared to be normal; but cabin pressure continued to climb at a slow steady rate. At that time the first officer placed his oxygen mask on; and I proceeded to pass the flight controls to him as I went to call dispatch on a commercial radio service. We asked for lower which we got; shortly thereafter I went ahead and put my oxygen mask on before we got the cabin hi warning message. Aircraft cabin continued to climb to above 10;000 ft and the cabin hi message appeared. At some point I ask the first officer to declare an emergency and to get to 10;000 ft as soon as possible and to turn around and go back to the departure airport. When dispatch answered I advised them that we had a pressurization issue with the aircraft and that we are turning back to the departure airport and to notify maintenance control and that I would give them a call after we landed. Before we started down or while I was waiting for dispatch to answer the radio; I called the cabin to advised the flight attendants that we had a issue with the aircraft pressurization and that we are returning back and prepare for landing in about 25 minutes; also that I would get back to them shortly with more information. We safely got down to 10;000 ft and were cleared direct to the airport; at that point me and the first officer removed our O2 mask. With some time to kill; I got the weather and landing data and set up for landing. I next called the cabin to get a status of themselves and the passengers; and to tell them what happened again that we are going back and how much time and that I would make a cabin announcement shortly. They told me that they were ok as well as the passengers. After my cabin announcement; I gave ATC a call and gave them and updated status that everything was ok and that we were no longer in an emergency situation; which they acknowledged. We transferred the aircraft controls back to me and we landed at the departure airport without any further problems. During my preflight of the maintenance logbook; I noticed that the day prior this aircraft had a similar incident after departing and had to return. Maintenance could not duplicate the problem and the aircraft was signed off.

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Original NASA ASRS Text

Title: An ERJ-190 cabin altitude exceed 10;000 FT in cruise at FL300 so an emergency was declared; the aircraft descended and returned to the departure airport where it was discovered the same anomaly occurred the previous day.

Narrative: After level off at FL300; just established at cruise; my First Officer noticed that the cabin pressure was climbing slowly through 8;500 FT. We temporary descended to FL280 to see if would stop or go down and pulled up the ECS page; everything appeared to be normal; but cabin pressure continued to climb at a slow steady rate. At that time the First Officer placed his oxygen mask on; and I proceeded to pass the flight controls to him as I went to call Dispatch on a commercial radio service. We asked for lower which we got; shortly thereafter I went ahead and put my oxygen mask on before we got the Cabin Hi warning message. Aircraft cabin continued to climb to above 10;000 FT and the Cabin Hi message appeared. At some point I ask the First Officer to declare an emergency and to get to 10;000 FT as soon as possible and to turn around and go back to the departure airport. When Dispatch answered I advised them that we had a pressurization issue with the aircraft and that we are turning back to the departure airport and to notify Maintenance Control and that I would give them a call after we landed. Before we started down or while I was waiting for Dispatch to answer the radio; I called the cabin to advised the flight attendants that we had a issue with the aircraft pressurization and that we are returning back and prepare for landing in about 25 minutes; also that I would get back to them shortly with more information. We safely got down to 10;000 FT and were cleared direct to the airport; at that point me and the First Officer removed our O2 mask. With some time to kill; I got the weather and landing data and set up for landing. I next called the cabin to get a status of themselves and the passengers; and to tell them what happened again that we are going back and how much time and that I would make a cabin announcement shortly. They told me that they were OK as well as the passengers. After my cabin announcement; I gave ATC a call and gave them and updated status that everything was OK and that we were no longer in an emergency situation; which they acknowledged. We transferred the aircraft controls back to me and we landed at the departure airport without any further problems. During my preflight of the maintenance logbook; I noticed that the day prior this aircraft had a similar incident after departing and had to return. Maintenance could not duplicate the problem and the aircraft was signed off.

Data retrieved from NASA's ASRS site as of July 2013 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.