Bae-125-800XP number 2 engine thrust reverser would not deploy while completing the taxi checklist. ...

Narrative:

The aircraft had been in maintenance for a left thrust reverser that was slow to deploy. Our mechanics at ZZZ deferred the thrust reverser; placarded it inoperative; and locked it out from functioning per our company MEL. After we started the aircraft and while completing the taxi checklist; we discovered that the right thrust reverser would not deploy either. We tried several times and it would not deploy. Our mechanics had locked-out both thrust reversers. We called our mechanics at ZZZ and they came right out to the airplane; observed the situation; and advised us to shut down the right engine. They went out to the right engine and removed the thrust reverser lockout device. They instructed us to restart the right engine and perform the thrust reverser check. The thrust reverser deployed as required. We then continued the flight to ZZZ1.there is no way the flight crew could have discovered this during an external preflight inspection. It was found during the taxi checklist. This could have been avoided if the mechanics would have removed the lockout device prior to return to service.

Original NASA ASRS Text

Title: BAE-125-800XP Number 2 engine thrust reverser would not deploy while completing the Taxi Checklist. Maintenance had already deferred the Number 1 reverser; but failed to remove the Number 2 lockout device prior to returning the aircraft to service.

Narrative: The aircraft had been in maintenance for a left thrust reverser that was slow to deploy. Our mechanics at ZZZ deferred the thrust reverser; placarded it inoperative; and locked it out from functioning per our company MEL. After we started the aircraft and while completing the Taxi Checklist; we discovered that the right thrust reverser would not deploy either. We tried several times and it would not deploy. Our mechanics had locked-out both thrust reversers. We called our mechanics at ZZZ and they came right out to the airplane; observed the situation; and advised us to shut down the right engine. They went out to the right engine and removed the Thrust Reverser Lockout device. They instructed us to restart the right engine and perform the Thrust Reverser Check. The thrust reverser deployed as required. We then continued the flight to ZZZ1.There is no way the flight crew could have discovered this during an external preflight inspection. It was found during the Taxi Checklist. This could have been avoided if the mechanics would have removed the lockout device prior to return to service.

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	941273
Time
Date	201103
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	BAe 125 Series 800
Operating Under FAR Part	Part 91
Flight Phase	Parked
Component
Aircraft Component	Turbine Engine
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural MEL Deviation - Procedural Published Material / Policy

Bae-125-800XP number 2 engine thrust reverser would not deploy while completing the taxi checklist. Maintenance had already deferred the number 1 reverser; but failed to remove the number 2 lockout device prior to returning the aircraft to service.