Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation - Altitude Undershoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance; Flight Crew Overcame Equipment Problem
Aircraft; Procedure; Human Factors
After climbing through the flap retraction altitude we executed the After Takeoff Checklist. We were in icing conditions immediately after takeoff with the APU running the pack. This flight was operated with a deferred right pack. The bleed source was transferred from the APU to the engines causing the single pack to shut down due to an over pressure event. At this point we both realized we were no longer pressurizing the aircraft. I proceeded to transfer the radios to the Captain (pilot flying) and followed the QRH procedure for L PACK HIGH PRESSURE msg. The Captain simultaneously shallowed our climb to prevent a future high cabin altitude situation from arising. At some point on the departure ATC issued us a heading off the SID; I believe because we had shallowed our climb and were in danger of missing a crossing restriction on the RNAV SID. I cannot be certain because I was heads down in the QRH. At this time the Captain informed ATC of our issue and asked for a heading and an altitude to keep us below 10;000 FT MSL. We were assigned a heading; and an altitude of 7;000 FT. Shortly after these events I finished the QRH procedure and restored the pack to normal operation. The flight continued and we rejoined the RNAV SID and continued to our destination without further incident. The biggest threat was the distraction from the SID due to the concern for aircraft pressurization resulting in a shallower than normal ascent. The flight crew should have informed ATC of the pressurization issue earlier especially since we were on an RNAV SID with crossing restrictions. Another threat was the division of tasks during the execution of the abnormal procedures. The tasks were divided but we found that both pilots were watching over each other and trying to help when able which at times caused confusion or further distraction from the tasks at hand. Better discipline in division of duties as well as keeping ATC more involved in our status.
CRJ200 First Officer reports being dispatched with a single pack and using the APU as the bleed source for takeoff. When the bleed source is switched to the engines after flap retraction an over pressure occurs and the pack shuts down. QRH procedures are used to restore the pack and the flight continues to destination; although a crossing restriction may have been missed on the RNAV departure.