A C172 CFI report on the temporary loss of left braking by his student and the unsatisfactory respon...

Attributes
ACN	517169
Time
Date	200107
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	ground : taxi ground : position and hold
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor
Qualification	pilot : cfi pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 25 flight time total : 2050 flight time type : 275
ASRS Report	517169
Person 2
Affiliation	other
Function	instruction : trainee
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Experience	flight time type : 600
Events
Anomaly	aircraft equipment problem : critical conflict : ground critical excursion : runway ground encounters other maintenance problem : improper maintenance other anomaly other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : unable other
Consequence	other other other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Company
Primary Problem	Aircraft

Narrative:

I was acting in the capacity as flight instructor. I was in the process of checking out a commercial pilot who has instrument and multi-engine ratings in addition to his commercial rating. I had flown with him before in the same make and model aircraft. I had not signed him off, however, at this point. We taxied to the runup area adjacent to the runway prior to release. I held the toe brakes during the runup. Everything seemed ok. After runup the pilot in the l-hand seat called the tower, announced ready for takeoff, and he received clearance to 'position and hold.' I had released the brakes previously and announced, 'I have released the brakes.' as the l-hand pilot taxied toward the runway, he suddenly announced, 'I've lost the left brakes!' the aircraft turned sharply to the right. Power was pulled back and both of us tried to apply the brakes. Instinctively, I pumped the brakes several times, but the aircraft taxied off the asphalt anyway and the propeller struck a taxiway light. This did minor damage to one blade. The engine was still running and we shut the engine down. We had the aircraft towed back to the FBO for inspection and repair. The mechanics reported that the brakes seemed to be working ok now. Photos were taken that showed skid marks on the taxiway. The r-hand tire was scuffed. (The skid marks were only over the last 20 ft of the asphalt.) I don't know, at this time, why the l-hand brake went out. I just know that it did. I am very concerned that it may go out again. Perhaps the same aircraft with a student landing could result in a much more serious incident. I am also concerned that the FBO is not looking into the cause of the loss of the brake problem and is concentrating on trying to assess blame on the l-hand seat pilot and myself. I have numerous hours in that make and model and the l-hand seat pilot has approximately 600-700 hours. You just don't suddenly veer right and run off the runway for no reason if you are an experienced pilot. There is something wrong in the brake system on this aircraft.

Original NASA ASRS Text

Title: A C172 CFI RPT ON THE TEMPORARY LOSS OF L BRAKING BY HIS STUDENT AND THE UNSATISFACTORY RESPONSE FROM THE FBO WITH REGARDS TO THE CAUSE OF THE FAILURE AT ZZZ, US.

Narrative: I WAS ACTING IN THE CAPACITY AS FLT INSTRUCTOR. I WAS IN THE PROCESS OF CHKING OUT A COMMERCIAL PLT WHO HAS INST AND MULTI-ENG RATINGS IN ADDITION TO HIS COMMERCIAL RATING. I HAD FLOWN WITH HIM BEFORE IN THE SAME MAKE AND MODEL ACFT. I HAD NOT SIGNED HIM OFF, HOWEVER, AT THIS POINT. WE TAXIED TO THE RUNUP AREA ADJACENT TO THE RWY PRIOR TO RELEASE. I HELD THE TOE BRAKES DURING THE RUNUP. EVERYTHING SEEMED OK. AFTER RUNUP THE PLT IN THE L-HAND SEAT CALLED THE TWR, ANNOUNCED READY FOR TKOF, AND HE RECEIVED CLRNC TO 'POS AND HOLD.' I HAD RELEASED THE BRAKES PREVIOUSLY AND ANNOUNCED, 'I HAVE RELEASED THE BRAKES.' AS THE L-HAND PLT TAXIED TOWARD THE RWY, HE SUDDENLY ANNOUNCED, 'I'VE LOST THE L BRAKES!' THE ACFT TURNED SHARPLY TO THE R. PWR WAS PULLED BACK AND BOTH OF US TRIED TO APPLY THE BRAKES. INSTINCTIVELY, I PUMPED THE BRAKES SEVERAL TIMES, BUT THE ACFT TAXIED OFF THE ASPHALT ANYWAY AND THE PROP STRUCK A TXWY LIGHT. THIS DID MINOR DAMAGE TO ONE BLADE. THE ENG WAS STILL RUNNING AND WE SHUT THE ENG DOWN. WE HAD THE ACFT TOWED BACK TO THE FBO FOR INSPECTION AND REPAIR. THE MECHS RPTED THAT THE BRAKES SEEMED TO BE WORKING OK NOW. PHOTOS WERE TAKEN THAT SHOWED SKID MARKS ON THE TXWY. THE R-HAND TIRE WAS SCUFFED. (THE SKID MARKS WERE ONLY OVER THE LAST 20 FT OF THE ASPHALT.) I DON'T KNOW, AT THIS TIME, WHY THE L-HAND BRAKE WENT OUT. I JUST KNOW THAT IT DID. I AM VERY CONCERNED THAT IT MAY GO OUT AGAIN. PERHAPS THE SAME ACFT WITH A STUDENT LNDG COULD RESULT IN A MUCH MORE SERIOUS INCIDENT. I AM ALSO CONCERNED THAT THE FBO IS NOT LOOKING INTO THE CAUSE OF THE LOSS OF THE BRAKE PROBLEM AND IS CONCENTRATING ON TRYING TO ASSESS BLAME ON THE L-HAND SEAT PLT AND MYSELF. I HAVE NUMEROUS HRS IN THAT MAKE AND MODEL AND THE L-HAND SEAT PLT HAS APPROX 600-700 HRS. YOU JUST DON'T SUDDENLY VEER R AND RUN OFF THE RWY FOR NO REASON IF YOU ARE AN EXPERIENCED PLT. THERE IS SOMETHING WRONG IN THE BRAKE SYS ON THIS ACFT.

Data retrieved from NASA's ASRS site as of July 2007 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.

A C172 CFI report on the temporary loss of left braking by his student and the unsatisfactory response from the FBO with regards to the cause of the failure at ZZZ, us.