Date: 202105
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: PA-34-200T Turbo Seneca II
Operator: FBO
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Landing
ATC / advisory: Tower ZZZ
Aircraft component: Brake System
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Pilot Flying; Trainee; Student
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument
Human factors: Troubleshooting; Training / Qualification; Situational Awareness; Distraction; Confusion; Workload
Second reporter function: Instructor; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control; Ground Incursion Runway
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Regained Aircraft Control; Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Aircraft
Primary problem: Aircraft

Narrative: I was on a multi-engine add on training flight with my instructor in Aircraft X. Upon landing at ZZZ I experienced what appeared to be a complete left brake failure. I used right brake to slow down but the brake barely worked. Towards the end of the runway we still had a lot of speed. I tried pumping the left brake which resulted in a slight left turn. My instructor said 'I will help you with the brakes;' which I understood to mean that he will work the brakes so I took my feet off the brakes. He said that he had no brakes at which point I stepped back on the brakes. At this point; the left turn was more aggravated and we were on a trajectory to run over the side of the runway and into the runway lights. My instructor applied right engine power to avoid the lights and stay on the runway. At this point we were near the intersection to the intersecting runway and swerved onto that runway without clearance.We were able to slow down and stop and immediately exited the runway at the nearest intersection. Tower advised us of possible pilot deviation. Contacted Ground. Copied the Tower's number. We called the Tower and advised of the situation. I was later informed that my instructor had been aware of a brake issue with the plane; had the part in hand; but had not wanted to fix it yet so the plane can still be used to finish up instruction for a few students. He said the brakes on the right seat had not worked in weeks; which I was not aware of. The left seat brakes felt soft on previous flight but still allowed adequate braking. I did not notice any anomalies during the pre-flight.


Second narrative: Upon landing at ZZZ field on Runway XX pilot advised me that the brakes on his side were soft as were my side on the copilot side; so we both started to pump the brakes to try and regain brakes on either side. As we were pumping brakes we were getting to the end of the runway so I tried to use the hand brake which had no pressure in it either so I checked what my best option was. A taxiway was coming up to fast; not enough room to regain brakes in time before we ran off the taxiway; straight ahead the runway end lights; so getting onto the intersecting runway was that option so I told my student that I had the throttles and I skid the airplane with differential power onto the intersecting runway. By the time we had the airplane pointing down the runway my student had got his brakes back and was able to get the airplane stopped. I did not ask for permission to taxi onto the runway due to the time I had to make a split second decision on where to continue letting the aircraft roll so I looked down the runway and nobody was on final so I wanted the best chance to get our aircraft slowed down without running off and hitting any signs or buildings or hangers; so I used differential power to turn the airplane onto the intersecting runway.


Synopsis: PA-34-200T instructor pilot and student reported brake failure during landing roll so the instructor turned onto an intersecting runway to stop safely.