Date: 201210
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Emergency Extension System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Became Reoriented; General Maintenance Action; General Declared Emergency
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: After liftoff Captain called for gear up and I raised the landing gear handle to the up position and we noticed immediately that gear did not retract. Captain called for QRH and stated that he had the aircraft and the ATC communications. I worked checklist while Captain advised ATC that we were working a problem. Captain advised ATC that he wanted to return and requested ARF standby. I worked checklists and was able to determine that the reason the gear did not come up was most likely the manual gear access door not contacting switch under door. On preflight the door appeared closed. Landed uneventfully; cleared runway and taxied back to gate. At gate Captain wrote up incident in logbook and called Dispatch to advise. Also debriefed Maintenance Representative after maintenance action was complete and logbook signed off we were dispatched without incident.Manual gear access door appeared to have dirt and grime which seemed to foul the latch. I could pop the door open with my finger nails even though it appeared fully closed. Flight Manual calls to check door closed on preflight. I checked door and it appeared closed. There is no way that I know to check if the switch under the access door is depressed until you raise the gear handle and find out your hydraulics have been deactivated due to the door not being fully seated. I don't know what the maintenance cycle is on this door or the switch but it should be routinely cleaned and lubricated to prevent future incidents of this nature.


Second narrative: Gear failed to retract after take off. First Officer worked the QRH; initially to no availability. The First Officer noticed that the manual gear extension door would not seat properly as directed by the QRH. As he worked the door; it finally seated and the gear retracted. I had all ready informed ATC that we would be returning. We returned where Maintenance lubed and removed debris from the manual gear extension door area. As a precaution; an emergency was declared and rescue team was requested; [we] landed uneventfully. Spilled liquid and crumbs accumulate in and around the manual gear extension door making it difficult operate the door. Regular periodic maintenance to clean the finger grab and door area would prevent this from being an issue.


Synopsis: B737-800 flight crew reports failure of the landing gear to retract after takeoff. During QRH procedures it is determined that the manual gear extension door is not seated properly and not contacting the switch below. The gear retracts when the door is properly seated but the crew elects to return for maintenance.