Narrative:

We were originally scheduled to operate a revenue flight. We swapped into a new aircraft and during our preflight duties it was discovered that there was a soft floorboard in the first class section of the aircraft. Maintenance was called. We were informed it would take approximately two hours to fix and then we would be good to go. The issue was finally fixed eight hours later. With the extensive delay the original flight was canceled and we were rescheduled to reposition the aircraft back as a part 91 flight; and end our day. I went and got our new paperwork while my first officer prepared the aircraft for departure. A walk around inspection had been completed when we first arrived at the aircraft as was required; but we did not think to do a second one. We had never left the aircraft during the maintenance delay; and had been outside the aircraft numerous times talking to the ramp workers and gate agents and had not seen anything out of the ordinary. A last minute walk around before departure is also not required by our SOP; and it did not cross our minds. We departed and began our climb. During the climb we noticed the cabin altitude was climbing faster than normal; but attributed it to the faster than normal climb rate due to flying an empty airplane on a repositioning flight. We continued to monitor the cabin altitude as we climbed. The cabin climb rate began to slow down; but the cabin altitude was still higher than normal. By this time we had been cleared up to FL270. Seeing the cabin altitude continue to climb past a value we considered normal for our current altitude we decided to try switching cabin pressure controllers; to see if the active one was malfunctioning. There was no noticeable change after the switch. As the cabin altitude approached 8;000 ft; we put on our oxygen masks in anticipation of not being able to get the cabin back under control and started to run the manual pressurization checklist. About this time we received the cabin altitude amber caution message; which leads to this same procedure. I took the radios; while my first officer ran the checklist. Right about this time we were leveling out at FL270 when we received the cabin altitude red master warning message. With the system in manual mode and full cabin descent the cabin was still climbing at 700 FPM. I called ATC and informed them we had a pressurization problem; requested and received a descent to 10;000 ft and declared an emergency at this time. My first officer continued to run the checklists while I descended the aircraft and began our return to our departure airport. The cabin altitude peaked at 10;300 ft and then began falling as we descended. Once we were below 10;000 ft MSL; and the cabin pressure was back in the normal range; we informed ATC that we had the cabin pressure at a safe level and would be making a precautionary landing. We did not request the fire and rescue equipment. We landed uneventfully 32 minutes after takeoff. We had been in contact with maintenance and dispatch during the return to our departure airport. Maintenance was waiting for us when we pulled into our gate and the problem was written up. My crew and I then went to the hotel to sleep. After our rest period; I got a call from the company informing me that maintenance had found that the lavatory dump valve had been left open; which was the reason the aircraft could not maintain pressure. At some point before we left; the ground crew had decided the aircraft was going to overnight and decided to dump the lavatory fluid so it wouldn't freeze overnight. In the process they did not close the valve when they finished like they normally would. During our push from the gate the push crew also apparently did not follow procedure and do a walk around to make sure any panels that had been opened by the ground crew had been closed prior to flight. We (the flight crew) are not required to make a second walk around inspection; as panels anddoors are routinely opened and closed during a turn and it is assumed everyone is trained properly and follows procedures. In the future; I will probably take the time to accomplish a secondary walk around inspection; whenever we have a long delay at the gate with the door open.

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Original NASA ASRS Text

Title: A Captain reports that a scheduled flight was canceled due to a soft floorboard in the first class section of their CRJ-700. The subsequent ferry flight required an air turn back to the same departure airport due to the lavatory dump valve had been left opened; preventing aircraft from pressurizing.

Narrative: We were originally scheduled to operate a revenue flight. We swapped into a new aircraft and during our preflight duties it was discovered that there was a soft floorboard in the first class section of the aircraft. Maintenance was called. We were informed it would take approximately two hours to fix and then we would be good to go. The issue was finally fixed eight hours later. With the extensive delay the original flight was canceled and we were rescheduled to reposition the aircraft back as a Part 91 flight; and end our day. I went and got our new paperwork while my First Officer prepared the aircraft for departure. A walk around inspection had been completed when we first arrived at the aircraft as was required; but we did not think to do a second one. We had never left the aircraft during the maintenance delay; and had been outside the aircraft numerous times talking to the ramp workers and gate agents and had not seen anything out of the ordinary. A last minute walk around before departure is also not required by our SOP; and it did not cross our minds. We departed and began our climb. During the climb we noticed the cabin altitude was climbing faster than normal; but attributed it to the faster than normal climb rate due to flying an empty airplane on a repositioning flight. We continued to monitor the cabin altitude as we climbed. The cabin climb rate began to slow down; but the cabin altitude was still higher than normal. By this time we had been cleared up to FL270. Seeing the cabin altitude continue to climb past a value we considered normal for our current altitude we decided to try switching cabin pressure controllers; to see if the active one was malfunctioning. There was no noticeable change after the switch. As the cabin altitude approached 8;000 FT; we put on our oxygen masks in anticipation of not being able to get the cabin back under control and started to run the manual pressurization checklist. About this time we received the CABIN ALT amber caution message; which leads to this same procedure. I took the radios; while my First Officer ran the Checklist. Right about this time we were leveling out at FL270 when we received the CABIN ALT red Master Warning message. With the system in Manual Mode and full cabin descent the cabin was still climbing at 700 FPM. I called ATC and informed them we had a pressurization problem; requested and received a descent to 10;000 FT and declared an emergency at this time. My First Officer continued to run the checklists while I descended the aircraft and began our return to our departure airport. The cabin altitude peaked at 10;300 FT and then began falling as we descended. Once we were below 10;000 FT MSL; and the cabin pressure was back in the normal range; we informed ATC that we had the cabin pressure at a safe level and would be making a precautionary landing. We did not request the fire and rescue equipment. We landed uneventfully 32 minutes after takeoff. We had been in contact with Maintenance and Dispatch during the return to our departure airport. Maintenance was waiting for us when we pulled into our gate and the problem was written up. My crew and I then went to the hotel to sleep. After our rest period; I got a call from the company informing me that Maintenance had found that the lavatory dump valve had been left open; which was the reason the aircraft could not maintain pressure. At some point before we left; the ground crew had decided the aircraft was going to overnight and decided to dump the lavatory fluid so it wouldn't freeze overnight. In the process they did not close the valve when they finished like they normally would. During our push from the gate the push crew also apparently did not follow procedure and do a walk around to make sure any panels that had been opened by the ground crew had been closed prior to flight. We (the Flight Crew) are not required to make a second walk around inspection; as panels anddoors are routinely opened and closed during a turn and it is assumed everyone is trained properly and follows procedures. In the future; I will probably take the time to accomplish a secondary walk around inspection; whenever we have a long delay at the gate with the door open.

Data retrieved from NASA's ASRS site as of April 2012 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.