Narrative:

Maintenance arrived after exterior aircraft preflight, during cockpit preflight, to perform maintenance requested by previous cockpit crew (scratchy external intercom sound quality). They took cockpit logbook and just before pushback, returned logbook to cockpit with interphone write up signed off. On takeoff leg, following gear retraction, a loud, pronounced, and steady vibration shook the nose wheel area of the aircraft. Landing gear was reextended, an emergency declared, and an uneventful turn to downwind and a visual landing accomplished. Upon return to the gate, it was discovered that the maintenance personnel, upon hearing that we had returned to the airport for nosewheel area structural vibration, voluntarily admitted that they had unlocked the nose wheel doors to gain access to the wheel well in order to perform interphone maintenance procedures and had forgotten to close them even though they had signed off their maintenance procedure. Swift disciplinary action was taken on the maintenance personnel. There is no way to tell if such a condition exists from the cockpit! All indications were normal except for the buffeting after gear retraction! Gear door lights are only for main gear doors. Except for the confessions of the maintenance personnel, I suspect that the cockpit crew would have initially been suspect.

Google
 

Original NASA ASRS Text

Title: ACR MLG MADE A TKOF WITH THE NOSE GEAR DOORS OPEN AND DISCONNECTED FROM THE ACTUATOR.

Narrative: MAINT ARRIVED AFTER EXTERIOR ACFT PREFLT, DURING COCKPIT PREFLT, TO PERFORM MAINT REQUESTED BY PREVIOUS COCKPIT CREW (SCRATCHY EXTERNAL INTERCOM SOUND QUALITY). THEY TOOK COCKPIT LOGBOOK AND JUST BEFORE PUSHBACK, RETURNED LOGBOOK TO COCKPIT WITH INTERPHONE WRITE UP SIGNED OFF. ON TKOF LEG, FOLLOWING GEAR RETRACTION, A LOUD, PRONOUNCED, AND STEADY VIBRATION SHOOK THE NOSE WHEEL AREA OF THE ACFT. LNDG GEAR WAS REEXTENDED, AN EMER DECLARED, AND AN UNEVENTFUL TURN TO DOWNWIND AND A VISUAL LNDG ACCOMPLISHED. UPON RETURN TO THE GATE, IT WAS DISCOVERED THAT THE MAINT PERSONNEL, UPON HEARING THAT WE HAD RETURNED TO THE ARPT FOR NOSEWHEEL AREA STRUCTURAL VIBRATION, VOLUNTARILY ADMITTED THAT THEY HAD UNLOCKED THE NOSE WHEEL DOORS TO GAIN ACCESS TO THE WHEEL WELL IN ORDER TO PERFORM INTERPHONE MAINT PROCS AND HAD FORGOTTEN TO CLOSE THEM EVEN THOUGH THEY HAD SIGNED OFF THEIR MAINT PROC. SWIFT DISCIPLINARY ACTION WAS TAKEN ON THE MAINT PERSONNEL. THERE IS NO WAY TO TELL IF SUCH A CONDITION EXISTS FROM THE COCKPIT! ALL INDICATIONS WERE NORMAL EXCEPT FOR THE BUFFETING AFTER GEAR RETRACTION! GEAR DOOR LIGHTS ARE ONLY FOR MAIN GEAR DOORS. EXCEPT FOR THE CONFESSIONS OF THE MAINT PERSONNEL, I SUSPECT THAT THE COCKPIT CREW WOULD HAVE INITIALLY BEEN SUSPECT.

Data retrieved from NASA's ASRS site as of July 2007 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.