A B737-700's L-1 door failed to seal when closed prior to takeoff. The aircraft would not pressurize...

Narrative:

Lead flight attendant chimed the cockpit after takeoff at 2;000 ft to report extremely loud air noise at L-1 door. Climbed to 5;000 ft and 240 KTS. Cabin pressurization not normal and climbing at over 1;000 FPM. Elected to air return to the departure airport. Informed passenger and ATC. Landing was uneventful. Deplaned all 39 customers. Contract maintenance had us pressurize the aircraft while he searched for air leaks at L-1 door; which were found. Depressurized aircraft and lubed door seal. Re-pressurized aircraft and no leaks found. Obtained a ferry permit and re-dispatched to a maintenance base far part 91. Turned aircraft over to maintenance. Return flight to destination at FL320 proved uneventful. Maintenance findings discovered a problem with the internal door mechanism. Perhaps a 500 hour check of the door mechanism might be in order to stay on top of this. Seems to be a recurring problem with the 737 L-1 door; from what I learned from maintenance.

Original NASA ASRS Text

Title: A B737-700's L-1 door failed to seal when closed prior to takeoff. The aircraft would not pressurize so the crew returned to land where Maintenance found that an internal door mechanism failed to position the door seal properly.

Narrative: Lead Flight Attendant chimed the cockpit after takeoff at 2;000 FT to report extremely loud air noise at L-1 door. Climbed to 5;000 FT and 240 KTS. Cabin pressurization not normal and climbing at over 1;000 FPM. Elected to air return to the departure airport. Informed passenger and ATC. Landing was uneventful. Deplaned all 39 customers. Contract maintenance had us pressurize the aircraft while he searched for air leaks at L-1 door; which were found. Depressurized aircraft and lubed door seal. Re-pressurized aircraft and no leaks found. Obtained a ferry permit and re-dispatched to a Maintenance Base FAR Part 91. Turned aircraft over to Maintenance. Return flight to destination at FL320 proved uneventful. Maintenance findings discovered a problem with the internal door mechanism. Perhaps a 500 hour check of the door mechanism might be in order to stay on top of this. Seems to be a recurring problem with the 737 L-1 door; from what I learned from Maintenance.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	936960
Time
Date	201102
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Component
Aircraft Component	Exterior Pax/Crew Door
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

A B737-700's L-1 door failed to seal when closed prior to takeoff. The aircraft would not pressurize so the crew returned to land where maintenance found that an internal door mechanism failed to position the door seal properly.