Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 50; Flight Crew Total 850; Flight Crew Type 200
Communication Breakdown; Situational Awareness; Training / Qualification
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control; Ground Incursion Runway
Flight Crew Regained Aircraft Control; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft; Human Factors; Procedure
After startup with a student; we performed a brake check; both sides; with a positive exchange of controls and no issues. After receiving our taxi clearance for an intersection departure; I observed my student taxiing faster than usual; and off centerline. I told him to slow down and bring the aircraft back to centerline; and he informed me there was a problem with the right brake. I took control; was unable to slow the aircraft; and with the runway hold short line approaching notified ground of my inability to stop. I swung to the right; and used brake to perform a 180 degree turn at speed; but wasn't able to turn tight enough to avoid crossing. I notified tower of my crossing; and cleared the runway environment. I got a clearance to taxi back to parking; where we ended the attempted flight; and shut the aircraft down until maintenance could diagnose and resolve the issue.
Flight Instructor reported a runway incursion due to brake failure and loss of control of the aircraft.