Date: 202004
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Skynight 320
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Personal
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Aircraft component: Brake System
Component problem: Failed
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Multiengine
Anomaly: Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I was given taxi clearance At ZZZ. My clearance was for XX via A; B1. As I taxied from the ; a grey and blue Cirrus taxied from general parking taking A in front of me; not too close as to cause issue. As we neared B1 the Cirrus slowed considerably resulting in my needing to apply brakes to slow. As I applied brakes; the right functioned normally whilst the left was unresponsive or had little to no effect on performance. As such the aircraft veered right. As I was also needing to still slow down I cut the throttles to their rear stops hard. This caused the right engine to quit resulting in the aircraft veering even more to the right. I was applying full left rudder as well with little affect. The aircraft veered far to the right of the taxiway; resulting in the right main and the nose gear to leave the pavement. The aircraft came to a stop with the nose gear and right main in the sod. The right main sunk down considerably causing a delay in returning the aircraft to the pavement. A mechanic was called out and assisted in recovery of the aircraft. He visually inspected the aircraft and deemed it airworthy with no damage sustained. In thinking back to the chain of events leading up to it; I think I could have better anticipated the aircraft ahead of me slowing. If they were given the same clearance I was they would have been slowing for the turn on to B1. However; they continued to the run up area at A1; so they may have been confused on their clearance and that is why they slowed when they did as well. I have experienced similar issues with the left main on this aircraft in the last few months and have worked with our maintenance department to resolve the issue. On 3 different occasions during run-up the left main would quit functioning and the aircraft would begin to turn to the right and on one occasion while slowing to make a left turn to park the left brake quit functioning and I had to pull the mixtures to kill the engines to stop since the only brake I had was the right which was causing the airplane to turn to the right heading off the pavement. The brake has been serviced and a seal replaced which seemed to fix the issue for the last month or so. Had I pulled the mixtures instead of the throttles I might have been able to keep the aircraft on the pavement or had I not cut the throttles so forcefully. However; when the aircraft started doing something opposite my commands I pulled them back harder than I should have. I will be mindful of taxi speed in the future while we work to resolve the issue. I feel the speed I was taxiing at the time was reasonable; but with the ongoing brake issue I will err on the side of caution.




Synopsis: C-320 pilot reported loss of directional control during taxi due to a right main brake failure resulting in a taxiway excursion.