An air carrier light transport had to return land because of a vibration.

Attributes
ACN	252672
Time
Date	199309
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : cvg
State Reference	OH
Altitude	agl bound lower : 0 agl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : cvg tower : cvg
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	climbout : initial ground : preflight other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 275 flight time total : 7500 flight time type : 1500
ASRS Report	252672
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 11470 flight time type : 1225
ASRS Report	252660
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

First officer's attitude heading reference system had been working intermittently on previous flight. Maintenance was notified. Prior to departure, first officer conducted turnaround preflight, including nose gear doors which maintenance had opened to gain access to the avionics compartment. All doors appeared to be closed and locked. Vibration developed after gear retraction. Since the vibration would stop after lowering the gear, crew suspected a gear door would not fully close. As a safety precaution, crew elected to return to cvg and have maintenance investigate. After landing, inspection found left nose gear door open. Prior to relatching, the door was placed in the closed position, and it stayed in the closed position. Emphasis must be placed on preflight activities, whether it be aircraft acceptance or turnaround. Careful attention to doors cannot be overlooked. While the nose gear door appeared closed, only pulling down would verify it was fully closed and latched. Supplemental information from acn 252660: the tower supervisor made the decision to roll the crash equipment. When maintenance got to the aircraft, the left nosewheel door was open. The latch was closed. Inspection revealed nothing broken. The door could be closed and the latch closed, and not be engaged. The door would stay in the closed position, even though not latched.

Original NASA ASRS Text

Title: AN ACR LTT HAD TO RETURN LAND BECAUSE OF A VIBRATION.

Narrative: FO'S ATTITUDE HDG REF SYS HAD BEEN WORKING INTERMITTENTLY ON PREVIOUS FLT. MAINT WAS NOTIFIED. PRIOR TO DEP, FO CONDUCTED TURNAROUND PREFLT, INCLUDING NOSE GEAR DOORS WHICH MAINT HAD OPENED TO GAIN ACCESS TO THE AVIONICS COMPARTMENT. ALL DOORS APPEARED TO BE CLOSED AND LOCKED. VIBRATION DEVELOPED AFTER GEAR RETRACTION. SINCE THE VIBRATION WOULD STOP AFTER LOWERING THE GEAR, CREW SUSPECTED A GEAR DOOR WOULD NOT FULLY CLOSE. AS A SAFETY PRECAUTION, CREW ELECTED TO RETURN TO CVG AND HAVE MAINT INVESTIGATE. AFTER LNDG, INSPECTION FOUND L NOSE GEAR DOOR OPEN. PRIOR TO RELATCHING, THE DOOR WAS PLACED IN THE CLOSED POS, AND IT STAYED IN THE CLOSED POS. EMPHASIS MUST BE PLACED ON PREFLT ACTIVITIES, WHETHER IT BE ACFT ACCEPTANCE OR TURNAROUND. CAREFUL ATTN TO DOORS CANNOT BE OVERLOOKED. WHILE THE NOSE GEAR DOOR APPEARED CLOSED, ONLY PULLING DOWN WOULD VERIFY IT WAS FULLY CLOSED AND LATCHED. SUPPLEMENTAL INFO FROM ACN 252660: THE TWR SUPVR MADE THE DECISION TO ROLL THE CRASH EQUIP. WHEN MAINT GOT TO THE ACFT, THE L NOSEWHEEL DOOR WAS OPEN. THE LATCH WAS CLOSED. INSPECTION REVEALED NOTHING BROKEN. THE DOOR COULD BE CLOSED AND THE LATCH CLOSED, AND NOT BE ENGAGED. THE DOOR WOULD STAY IN THE CLOSED POS, EVEN THOUGH NOT LATCHED.

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.