Narrative:

Climbing out of 13;000 feet we observed an ECAM message '1 engine thrust reverser unlocked' and also noted a rev amber warning in number 1 engine N1 gauge. We stopped climb and ran ECAM checklist procedures during which we reduced number 1 engine thrust lever to idle where it remained the rest of flight. We declared an emergency and requested a return to our departure airport; contacted dispatch and maintenance control for a return to field and an overweight landing. The dispatcher concurred 'at captains discretion' via ACARS. The jump seat rider contacted operations advising of our return and also advised the flight attendants and passengers of our intent to return to the airport and that we expected a normal landing. We treated the approach and landing as a single engine approach with engine number 1 at idle thrust as per ECAM actions. Landing was made at 180;000 lbs with a vertical speed of 100 FPM at touchdown. We then taxied to the gate under own power.

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Original NASA ASRS Text

Title: An A321 returned to its departure airport uneventfully following receipt of a left engine reverser unlocked light during the initial climb to cruise.

Narrative: Climbing out of 13;000 feet we observed an ECAM message '1 ENG Thrust reverser unlocked' and also noted a REV amber warning in Number 1 ENG N1 gauge. We stopped climb and ran ECAM checklist procedures during which we reduced Number 1 ENG thrust lever to idle where it remained the rest of flight. We declared an emergency and requested a return to our departure airport; contacted Dispatch and Maintenance Control for a return to field and an overweight landing. The Dispatcher concurred 'At Captains discretion' via ACARS. The jump seat rider contacted operations advising of our return and also advised the flight attendants and passengers of our intent to return to the airport and that we expected a normal landing. We treated the approach and landing as a single engine approach with engine Number 1 at idle thrust as per ECAM actions. Landing was made at 180;000 lbs with a vertical speed of 100 FPM at touchdown. We then taxied to the gate under own power.

Data retrieved from NASA's ASRS site as of July 2013 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.