Date: 201501
Local time of day: 0601-1200
Location: ATL.Airport, GA
Flight conditions: VMC
Light: Daylight
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight phase: Climb
Airspace: Class B ATL
ATC / advisory: TRACON A80
Aircraft component: Service/Access Door
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Maintenance Action
Contributing factors: Human Factors; Procedure; Aircraft
Primary problem: Ambiguous

Narrative: Upon departure; aircraft did not seem to pressurize. After noting this we received an Auto Fail light on the pressurization panel. We proceeded to run the QRH and asked ATC for vectors and stay at 10;000 FT. Once we were directed to place the pressurization switch in standby mode we noted this did not fix the problem. I tried to ACARS Dispatch and contact MX Control on the radio with no luck. I decided to return to XXX for landing; as the aircraft would not pressurize. No emergency was declared. Upon extending the gear we noted a loud noise in the flight deck along with a vibration. Once we landed and returned to the gate I went out to check the E and E door and found that it was left open. There was no indication in the cockpit this door was open and the light pressed to test and checked normal. Maintenance met the aircraft and noted the same things and deferred the E and E door sensor. Double-check with First Officer that he was able to complete thorough preflight (with de-ice truck spraying the aircraft) during walkaround. Pay better attention when Crew Member is not familiar with the aircraft.


Second narrative: Upon landing; I turned my phone on; within 30 seconds; Scheduling was calling me; asking me to operate Flight X; XXX to XXX. I said no problem; Scheduling informed me it was due to depart in 15 minutes. I proceeded to the gate; and discovered I was the First Crew member to report. After checking in with the Agent; I asked about deicing for the active frost conditions; and was informed that we were to be deiced at the gate. I proceeded to the aircraft to check the logbook; and commence my preflight duties. I discovered; as the first person on the aircraft; the gear pins were already removed; but it appeared that Maintenance was just on the aircraft; and it may have been repositioned. I discovered that the APU was already running; was on the bus; and providing air; and there has been an alert for 'Duct Overheat' since arriving at the aircraft. I immediately turned down the left pack air temp; ran the QRH and reset the Duct Overheat alert. It successfully reset. I watched it for a few minutes to ensure it would not re-trip. After the safety check; I proceed outside to perform the walkaround. As I began; and I reached the nose of the aircraft; the Zone Supervisor and Assistant Station Manager were on the ramp; shouting to me to 'lookout; they are going to deice.' The deice truck had arrived and was prepared to commence deicing at the gate (before boarding). I got out of the way; and the operation began. When I resumed my walkaround inspection at the nose; I did make a point to examine the EE bay door; but did not notice anything unusual; in retrospect; I may not have gotten down to my knees on the deiced ramp to get low enough to look at the door clearly. I have several thousand hours on the 737 at another carrier; but I am not used to how low you have to get to properly ascertain the belly door is fully closed and latched on an old 737; straight wing aircraft. It is much lower to the ground; and harder to see. By the way; at 6' 5;' that is no easy feat anyway. The walkaround inspection completed; and deicing completed; I returned to the cockpit; the rest of the Crew arrived; and the Passengers boarded. We left in due course; no one feeling rushed. All checklists properly completed. We departed normally. On climbout; both the Captain and I noticed our ears popping. With the complicated RNAV Departure and a priority of flying the aircraft; we held off running any checklist until the aircraft was cleaned up. We shortly leveled off at 10;000 FT; told ATC we needed to stay at 10;000 FT and ran through the Pressurization 'Auto Fail' checklist. We had no control of pressurization in Auto or Standby and even ran the Rapid Depressurization checklist; despite that we did not have to don O2 masks or make an emergency descent. The pack and bleeds were in auto and the Air/Ground switch was verified in 'FLT'. We noted the outflow valve was fully closed. We had no lights; even ran a lights test; with no abnormal indications. We simply had no differential pressure; and cabin altitude was 10;000 FT. We did have an 'Auto Fail' and '''Standby''' indication on the pressurization panel. In standby; we still had no control of pressurization. We went to manual mode; and still had no control of pressurization. We ACARS'd Dispatch about the situation and suggested a return to XXX; which was agreed to. An emergency was not declared; we just needed to return for Maintenance. The Captain and I did a nice job splitting workload; I was very familiar with local XXX operations and reloaded the FMS for a return and approach to XXX and got ACARS messages to Dispatch while talking to ATC; while the Captain was talking to Company ops in XXX; the F/A's; and the Passengers. We accomplished a normal descent and arrival briefing and approach briefing and completed a Visual Approach. We noted a substantial increase in airflow noise as we lowered the landing gear; but all indications were normal. Landing and return to the gate were normal. Upon completing the Parking Checklist; we exited the aircraft; and discovered that the EE bay door was full open; and the cockpit light; while not burned out; indicated the door was shut. There were multiple opportunities to prevent this from happening. 1. Indication and warning systems are presumed to be functional when the airworthiness is signed off by Maintenance. 2. When an aircraft is returned to line service by Maintenance; either from a reposition or Maintenance checks; the aircraft should be verified (QA?) ready for line ops; and all Maintenance and service doors not in use should be verified closed; tools removed; connections made; etc. 3. The First Officer should catch a discrepancy such as an open door that is not normal (EE bay); which was specifically pointed out in training; despite the distractions of being re-Crewed; and deiced; and interruptions to the exterior inspection; and 4. The Tug Driver and Push Team should verify that all doors are shut and the aircraft is ready for flight. The failure to accomplish all four of these checks at the same time caused the air return. I cannot speak of the other three; but I was not as familiar with the older 737's; and thought I was doing an acceptable job of the inspection. Today's experience has shown that to not be the case this time.


Synopsis: B737-300 flight crew reports being unable to pressurize after takeoff. QRH procedures are complied with but still no pressurization and the flight returns to the departure airport. Post flight reveals that the E&E compartment door is open and the door warning system is inoperative.