Aircraft Equipment Problem Critical
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
Previous crew wrote up the aircraft for 'Low Airflow.' The inbound Captain and F/O both stated how airflow to the cockpit was very poor on the ground and on climbout. Maintenance troubleshooting revealed a faulty left pack. We coordinated with Dispatch (Mel 21-1a 'One pack Inop. pressurized Flt.) and re-planned the flight for FL240 with additional fuel. We reviewed 'Packs Off' performance data and discussed 'Packs Off' takeoff procedures. On takeoff at 400 FT 'Right Pack' reinstatement was negligible. Pressurization was slow to nonexistent due to low airflow and the cabin was climbing off schedule. Shortly thereafter the 'Pressurization Flow' Light came on. The outflow valve had moved to fully closed with the cabin still climbing off schedule. We followed the QRH Procedures; declared an 'Emergency' and immediately brought the plane back to land. The Captain accomplished a smooth and uneventful overweight landing.
MD82 First Officer reports being dispatched with one pack inoperative and discovering after takeoff that the remaining pack is also faulty. Flight returns to the departure airport.