Date: 201212
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Light: Night
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Aircraft Cooling System
Component problem: Improperly Operated; Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Workload; Distraction; Confusion; Communication Breakdown
Second reporter function: Pilot Not Flying; Relief Pilot
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: Pre-flight; In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Contributing factors: MEL; Manuals; Procedure
Primary problem: Ambiguous

Narrative: Aircraft arrived from hangar after B-Check at approximately twenty five minutes before departure. When we arrived at aircraft; the cabin temperature was warm and the flight deck temperature was hot. This was a concern to us due to the fact that the aircraft must be kept cool due to the EQPT COOLING MEL procedure.  During walk around; the Relief Pilot noticed forward equipment valve open with no airflow. He also noticed large amounts of water draining from the left pack area. Maintenance was at the aircraft and we brought these items to their attention. We did not have the logbook at this time to reference; but the flight plan did reference the FWD EQPT COOLING SUPPLY FAN which was on placard with the switch positioned to STBY and the valve light illuminated. During our discussion about the valve being open with no airflow; Maintenance indicated this was normal and it was our  understanding that the valve in question would close once airborne.  Concerning the water drainage from left pack; again Maintenance indicated this was a normal condition with certain aircraft and would stop once airborne. We wrote this condition up in the logbook for maintenance sign off. Maintenance looked further into this condition and found a water nozzle blocked thus creating the water issue. They cleaned the nozzle and signed off the discrepancy. While working on this issue; our left mid lavatory overflowed due to a rinse valve sticking on during flush cycle. This caused a spill large enough to have to deplane all passengers in order to vacuum and clean the area. Maintenance capped off the water supply line to this lavatory and placarded it inoperative.  Thinking that all was accomplished and after re-boarding; we taxied out for departure. While checking the EICAS messages on our checklist; FWD EQPT COOLING VALVE along with the VALVE light on the overhead panel (STBY selected) checked with the placarded item in the logbook. We departed. During climb at approximately 500 feet; we heard a loud pop followed by what seemed to be a large rush of air. The cabin rate of climb started to match the aircraft climb rate and you could feel the pressure in your ears. We decided to level off at 7;000 feet once we talked to departure about our situation. While cleaning the aircraft up and passing approximately 1;800-2;000 feet; the Equipment Cooling OVERHEAT light illuminated. We followed the QRH and positioned the Equipment Cooling Selector to OVRD. After a few minutes in OVRD; we received a NO COOLING light along with a Master Caution light.  With the pressurization not appearing to work and Equipment Cooling issues; we decided to declare an Emergency and make an overweight landing. Landing was smooth and normal on Runway 27 at a landing weight of 383;000 pounds. Brake usage was minimal as we rolled to the end of the runway. We then had the Fire Commander check the aircraft and brakes which was reported OK. We then had them follow us to the gate to check temperatures which could peak many minutes after landing. The report at the gate was all wheels except number 1 were cool with the number 1 below 400 degrees.  When Maintenance arrived at the gate; we were informed that the valve light on the overhead panel should not have been on. We checked the MEL prior to departure and no reference was made to the valve light being on or off after selecting STBY (which was the switch position when we arrived at aircraft) on the Equipment Cooling Panel. When Maintenance went to check the actual valve on the belly of the aircraft; they had to 'un-stick' the valve for free movement. The light extinguished on the flight deck but seemed slow to respond when Maintenance cycled the valve.  I would suggest adding what lights and EICAS messages should be seen on the flight deck when certain MEL procedures are accomplished in the (O) section of each MEL.


Second narrative: When confronted with the abnormal aircraft condition - EQ Cooling Door Open and no airflow; Maintenance should be able to confirm this is abnormal and NOT explain it as normal for the placard when it clearly was not. Event could and should have been avoided with Maintenance recognizing the improper position of the valve when I brought it to their attention. Perhaps the MEL could help pilots identify the improper condition if it stated to verify VALVE light extinguished.


Synopsis: A B767-300'S FWD EQPT COOLING SUPPLY FAN was MEL'ed and after takeoff the FWD EQPT COOLING VALVE failed to close; thus preventing pressurization and equipment cooling so an emergency was declared and the flight returned to the departure airport.