B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Total 16700
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Flight Crew Returned To Departure Airport; General Maintenance Action
Procedure; Human Factors; Aircraft
Performed normal pre-flight walk around inspection. It was about one hour before sunrise so I used my flashlight in the performance of these duties. We conducted the cockpit preflight utilizing the normal checklists to include the new Departure Briefing procedure. The Captain and I discussed possible threats. We had not flown together before so all procedures were followed very thoughtfully; diligently and under no time constraints. I believe the Captain was setting the operational tone for the start of this sequence. Taxi conduct and procedures were normal and without incident. The takeoff was normal except unusual noise which we discovered was the forward equipment door which had opened. The Captain instructed me to request a level off at 4;000 feet. Departure Control complied with this request. After reviewing the situation Captain used his judgment not to declare an emergency which I concurred with. We requested an immediate return. We transferred controls of the aircraft as necessary to complete the checklists and for the Captain to speak with the Flight Attendants and passengers. An overweight landing was briefed and the Captain landed the aircraft smoothly and with a minimum rate of descent. We returned to the gate and Maintenance completed the proper inspections. When the inspections were completed and logbook returned we continued the flight to [destination airport]. The event occurred due to maintenance personnel closing the forward EQUIP access door and not latching it; and my failure to detect the latch in its improper position during my preflight inspection. The EQUIP door light will not illuminate until the door is opened regardless of the latch position. We had no EQUIP door light at any time while on the ground. As the last line of defense; I must be more diligent in closely looking at door latches during the hours of darkness. Maintenance must also remember that when a door is closed it must always be latched immediately.
B737-800 pilot reported Maintenance not latching forward equipment access door resulting in a return to departure airport.