Narrative:

I was the multi-engine flight instructor on a flight training mission in a piper seneca (PA34-200); which had just completed a 100 hour inspection 2 days prior. This particular seneca does not have toe-brakes for the right seat pilot (instructor's position). The instructor must rely upon an emergency hand brake should the student pilot need assistance. While flying the aircraft on the downwind leg of the airport traffic pattern; the pre-landing check was completed; and proper brake pressure was verified by the student. The aircraft was landed by the student without incident on the shorter of the 2 runways. The student was having difficulty tracking the centerline of the runway; however he did not state that he was having braking problems; xwinds were also present; and so deviations from the runway centerline appeared to be wind-related. At approximately 30 mph the student told me he was having problems braking; and the airplane was approaching the end of the runway. The airplane's right toe brake was 'spongy' and not working; however; the left brake was working. As he depressed the brakes; the airplane veered off to the left of the centerline. My control input from the right seat (with no brakes) was heavy right rudder to compensate for the induced left deviation caused by the student's braking. I said to the student 'my airplane' and pulled the handbrake; while continuing to apply right rudder so as not to run off the left side of the runway. The airplane veered hard to the right with hand braking. The airplane then left the runway on the right side at approximately 20 mph; crossed a flat area with weeds; and entered an open parking lot area without striking anything. No damage was done to airport property or the airplane. I was handed off to ground control; and I taxied the airplane very slowly with hand-braking roughly 50 ft to clear the airport movement area. Shortly after; the right braking system that had failed earlier was working fine; as it seemed to have been during the brake check on the downwind leg.

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Original NASA ASRS Text

Title: PA34 INSTRUCTOR AND STUDENT EXPERIENCE RWY EXCURSION AFTER A BRAKE FAILURE.

Narrative: I WAS THE MULTI-ENG FLT INSTRUCTOR ON A FLT TRAINING MISSION IN A PIPER SENECA (PA34-200); WHICH HAD JUST COMPLETED A 100 HR INSPECTION 2 DAYS PRIOR. THIS PARTICULAR SENECA DOES NOT HAVE TOE-BRAKES FOR THE R SEAT PLT (INSTRUCTOR'S POS). THE INSTRUCTOR MUST RELY UPON AN EMER HAND BRAKE SHOULD THE STUDENT PLT NEED ASSISTANCE. WHILE FLYING THE ACFT ON THE DOWNWIND LEG OF THE ARPT TFC PATTERN; THE PRE-LNDG CHK WAS COMPLETED; AND PROPER BRAKE PRESSURE WAS VERIFIED BY THE STUDENT. THE ACFT WAS LANDED BY THE STUDENT WITHOUT INCIDENT ON THE SHORTER OF THE 2 RWYS. THE STUDENT WAS HAVING DIFFICULTY TRACKING THE CTRLINE OF THE RWY; HOWEVER HE DID NOT STATE THAT HE WAS HAVING BRAKING PROBS; XWINDS WERE ALSO PRESENT; AND SO DEVS FROM THE RWY CTRLINE APPEARED TO BE WIND-RELATED. AT APPROX 30 MPH THE STUDENT TOLD ME HE WAS HAVING PROBS BRAKING; AND THE AIRPLANE WAS APCHING THE END OF THE RWY. THE AIRPLANE'S R TOE BRAKE WAS 'SPONGY' AND NOT WORKING; HOWEVER; THE L BRAKE WAS WORKING. AS HE DEPRESSED THE BRAKES; THE AIRPLANE VEERED OFF TO THE L OF THE CTRLINE. MY CTL INPUT FROM THE R SEAT (WITH NO BRAKES) WAS HVY R RUDDER TO COMPENSATE FOR THE INDUCED L DEV CAUSED BY THE STUDENT'S BRAKING. I SAID TO THE STUDENT 'MY AIRPLANE' AND PULLED THE HANDBRAKE; WHILE CONTINUING TO APPLY R RUDDER SO AS NOT TO RUN OFF THE L SIDE OF THE RWY. THE AIRPLANE VEERED HARD TO THE R WITH HAND BRAKING. THE AIRPLANE THEN LEFT THE RWY ON THE R SIDE AT APPROX 20 MPH; CROSSED A FLAT AREA WITH WEEDS; AND ENTERED AN OPEN PARKING LOT AREA WITHOUT STRIKING ANYTHING. NO DAMAGE WAS DONE TO ARPT PROPERTY OR THE AIRPLANE. I WAS HANDED OFF TO GND CTL; AND I TAXIED THE AIRPLANE VERY SLOWLY WITH HAND-BRAKING ROUGHLY 50 FT TO CLR THE ARPT MOVEMENT AREA. SHORTLY AFTER; THE R BRAKING SYS THAT HAD FAILED EARLIER WAS WORKING FINE; AS IT SEEMED TO HAVE BEEN DURING THE BRAKE CHK ON THE DOWNWIND LEG.

Data retrieved from NASA's ASRS site as of May 2009 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.