CE560XL flight crew reported a taxiway excursion when the right brake failed during taxi out.

Attributes
ACN	1541422
Time
Date	201805
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation Excel (C560XL)
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Normal Brake System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Less Severe Ground Excursion Taxiway

Narrative:

Aircraft was picked up after having maintenance work done on the brakes. As we began the taxi; both pilots verified brake pressure and that the brakes worked. We left the ramp area and began a taxi for departure. As we neared [an intersecting taxiway]; I applied more pressure to slow to make the turn. Both brakes felt as if I had positive pressure; however the aircraft began to veer left. Through my training on anti-skid brakes; I did not release pressure but continued to press on the brakes. I could feel the aircraft slowing; but was powerless to keep it from turning left and exiting the taxiway. Everything happened rather quickly and I did not have time to reach for and use the emergency brake. The plane came to a stop with the nose gear about 4 or 5 feet into the grass; however the mains were still on the taxiway. I set the parking brake and shut down the engines. We notified the tower that we were partially off the taxiway and then I phoned the company to notify them of the situation.there were no cockpit indications of a failure (low brake pressure or anti-skid). The aircraft was towed out of the grass without any signs of damage.I'm not sure of what I would suggest to do differently. I did review the logbook and saw the mechanic had bled the brakes and had also taxied the aircraft the night before.

Original NASA ASRS Text

Title: CE560XL flight crew reported a taxiway excursion when the right brake failed during taxi out.

Narrative: Aircraft was picked up after having maintenance work done on the brakes. As we began the taxi; both pilots verified brake pressure and that the brakes worked. We left the ramp area and began a taxi for departure. As we neared [an intersecting taxiway]; I applied more pressure to slow to make the turn. Both brakes felt as if I had positive pressure; however the aircraft began to veer left. Through my training on anti-skid brakes; I did not release pressure but continued to press on the brakes. I could feel the aircraft slowing; but was powerless to keep it from turning left and exiting the taxiway. Everything happened rather quickly and I did not have time to reach for and use the emergency brake. The plane came to a stop with the nose gear about 4 or 5 feet into the grass; however the mains were still on the taxiway. I set the parking brake and shut down the engines. We notified the Tower that we were partially off the taxiway and then I phoned the company to notify them of the situation.There were no cockpit indications of a failure (low brake pressure or anti-skid). The aircraft was towed out of the grass without any signs of damage.I'm not sure of what I would suggest to do differently. I did review the logbook and saw the mechanic had bled the brakes and had also taxied the aircraft the night before.

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.