EMB ERJ 145 ER/LR
Workload; Troubleshooting; Situational Awareness; Distraction; Confusion; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Departure Airport; General Maintenance Action; General Declared Emergency
Aircraft; Manuals; Procedure; Chart Or Publication
Climbing through about FL180 I noticed PACK 2 VLV CLD message and told the Captain I was going to reset it. I did with no problem. When we got to around FL260 I noticed the cabin altitude was around 9;300 FT and rising. It's usually around 7;600-7;700 FT. There were no annunciations at the time. We both agreed that we need to go back down at least to FL250. Captain started to get mask on and talk to ATC and I was working on getting us going down. Once I got us going down I put my mask on as the cabin altitude was passing slowly through 10;000 FT. Captain asked ATC for 250; then right after 10;000. They held us at FL240 for about 30 seconds for traffic below us and then we started down. In the mean-time Captain called Flight Attendant and told we were about to do an emergency descent to 10;000 FT. We got clearance to 11;000 and brought thrust levers to idle; speed brakes out and started down around 290 KTS. Captain said to slow down so he could get the gear out. We ran the Immediate Action Items at that point and he started on the QRH.ATC cleared us down to 10 and we leveled off there. Due to the workload and distractions we slowed down to 200 KTS at 10 and because of our weight were pitched up around 5-7 degrees. I added power to the detent and brought the speed back up to around 260. We then asked to go down lower to burn more fuel since we started to head back to departure airport once we leveled off. Captain; ran the QRH for pack and bleed problems at this point and isolated E2 bleeds and PACK 2. [We] flew around on vectors until we got below landing weight and landed with no more abnormalities.Threats were slow cabin depressurization; inexperienced First Officer; and high workload environment. Errors: Not following the emergency descent procedure exactly. We should have slowed to 250 KTS before starting down so we could put the gear out. The cabin altitude was not rising rapidly; so there wasn't an overwhelming sense of urgency. I also didn't keep a good scan going when we leveled off at 10;000 FT and got slow. I would consider when we were at 200 KTS as an unwanted aircraft state since I did not intend on getting that slow. Follow the procedures exactly as published.
The cabin depressurized a bit quicker when the engines were retarded for the descent. I realized it was more than just the faulty pack; the cabin aural warning was heard; and we decided to perform an emergency descent. I informed ATC of the situation and they cleared us to 24;000 momentarily for traffic then down to 11;000. I checked the seat belt sign was on; called the Flight Attendant while the First Officer began the descent again at idle power and spoilers deployed. That descent was almost immediate since we were slow to begin with from the steep climb. The cabin altitude leveled off at 10;500 FT and the First Officer elected to leave the gear up for the descent thinking the descent rate was sufficient. We later decided to lower the gear and speed our descent. BLEED 2 VLV CLD and PACK 2 VLV CLD messages were presented during the descent. Upon leveling off we slowed to 200 to retract the gear. The heavy fuel load (10;000 LBS) and configuration brought the pitch limit indicator into view at around 200 while leveling off and we slowed a bit further while the gear retracted at detent thrust. We turned toward our departure airport; got delaying vectors to burn fuel and landed. During delaying vectors the BLEED 2 VLV CLD and PACK 2 VLV CLD messages were presented. We ran the QRH for them and I concluded there was something wrong on the right side of the system. I closed the right valves and the cross feed valve to isolate the system. CauseThe bleed system suffered a leak somewhere on the right side of the system and caused the cabin to decompress. We erred during the descent by not effectively communicating the desired aircraft configuration and required performance but; we were pressed for time. That was an undesired aircraft state. We also were in an undesired aircraft state upon level off with our weight and configuration but; both identified the problem and quickly corrected. The 2 bleed valve and pack valves were operating erratically and I concluded that damage may have been sustained on the system. SuggestionsThe QRH procedure for bleed valve closed or pack valve closed calls for opening valves and opening the cross feed valve leaving them open. This resulted in bleed air from the left side of the system leaking into the belly somewhere from the ruptured line on the right side and not enough air to operate pack 1 or 2. A QRH procedure for when both bleed valve and pack valve closed messages are presented at the same time could be developed. Isolating the right side of the system would have stopped the loss of pressure and the flight may have continued at 25;000 on pack 1. But with a ruptured line on the right side the QRH continued to open pack 2 and bleed 2 losing pressure and causing an unknown bleed leak.
An EMB-145 developed a pneumatic system leak at FL260 which first alerted as BLEED 2 VLV CLD and PACK 2 VLV CLD as the cabin began climbing. An emergency was declared; the QRH completed and after leveling at 10;000 FT; the crew realized the QRH instruction to open the Crossfeed Valve allowed the left pneumatic system to dump into the malfunctioning right ducting.