B757 flight crew reported a thrust reverser was not deactivated properly.

Attributes
ACN	1456392
Time
Date	201706
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Fan Reverser
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL Deviation - Procedural Published Material / Policy Deviation - Procedural Maintenance

Narrative:

During preflight we noted that the left thrust reverser was MEL inoperative. White placard in logbook and sign off. We noted the MEL and sign off. We took off to ZZZ enroute we got a ACARS message to divert right to ZZZ1 that the lockout on the left TR was not done correctly inflight deployment could occur we got direct to ZZZ1 and landed. Gave plane to maintenance.plane had flown for a few days and somehow someone figured out that the lock was not done correctly. Flight crew followed MEL and it was good to them. Make sure job is done right the first time.

Original NASA ASRS Text

Title: B757 flight crew reported a thrust reverser was not deactivated properly.

Narrative: During Preflight we noted that the Left Thrust Reverser was MEL INOP. White Placard in Logbook and sign off. We noted the MEL and sign off. We took off to ZZZ enroute we got a ACARS Message to divert right to ZZZ1 that the lockout on the left TR was not done correctly inflight deployment could occur we got direct to ZZZ1 and Landed. Gave plane to Maintenance.Plane had flown for a few days and somehow someone figured out that the Lock was not done correctly. Flight crew followed MEL and it was good to them. Make sure job is done right the first time.

Data retrieved from NASA's ASRS site 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.