Narrative:

I was returning the aircraft from maintenance; where it had completed a 100-hour inspection. The flight was uneventful until landing rollout. As I applied the brakes; the aircraft began veering to the right. The more pressure I applied to the brakes; the more pronounced the problem became. As I was running out of runway and did not have enough left brake authority/authorized to stop on the centerline short of the runway end; I applied full brakes; which turned the aircraft sharply to the right. The aircraft came to rest with the nosewheel 2-3 inches off the runway edge. There was no damage to the aircraft or any airport property. Maintenance subsequently determined that 1 of the 4 brake pads on the left main gear was misaligned; causing only the misaligned pad to make contact with the disc; while all 4 pads were in contact with the disk on the right brake. This disparity in braking authority/authorized; therefore; became more pronounced as more pressure was applied. Unfortunately; the long runway at ZZZ was closed; and I was operating on the short runway; and had no choice but to turn the aircraft sideways to bring it to a stop. Contributing factors: 1) I have never experienced an asymmetric brake failure; and may not have reacted quickly enough to stop the aircraft on the centerline; if it was possible at all. 2) I had been at work since XA00; so fatigue may have been a factor. 3) although this was a mechanical problem; I have no doubt I would have been able to stop properly had the longer runway been available in ZZZ. Corrective actions: I believe that if the brake assemblies are removed for any reason; the brakes should be tested by conducting a test flight; or by performing a high speed taxi test. Callback conversation with reporter revealed the following information: reporter stated that maintenance informed him one of the brake disc pads on the left main gear brake assembly was not seated properly in the disc's rotor. As a result; this created a wider gap at the misaligned pad than normally exists when all four pads are properly seated against the disc (rotor) face surface. As he was applying greater pedal braking force; the misaligned pad on the left brake prevented normal braking action on the brake disc. This lower braking effect on the left brake allowed the right brake which was working fine; to become dominant causing the aircraft to turn sharply to the right. Reporter did not know if the MM procedure for the brake change required at least a minimum taxi brake test.

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Original NASA ASRS Text

Title: A CESSNA 421 PILOT; ON A RETURN FLIGHT FROM A JUST COMPLETED 100-HOUR INSPECTION; REALIZES HE HAS LIMITED LEFT BRAKE AUTHORITY AS THE ACFT VEERS SHARPLY TO THE RIGHT ON LANDING ROLLOUT.

Narrative: I WAS RETURNING THE ACFT FROM MAINT; WHERE IT HAD COMPLETED A 100-HR INSPECTION. THE FLT WAS UNEVENTFUL UNTIL LNDG ROLLOUT. AS I APPLIED THE BRAKES; THE ACFT BEGAN VEERING TO THE R. THE MORE PRESSURE I APPLIED TO THE BRAKES; THE MORE PRONOUNCED THE PROB BECAME. AS I WAS RUNNING OUT OF RWY AND DID NOT HAVE ENOUGH L BRAKE AUTH TO STOP ON THE CTRLINE SHORT OF THE RWY END; I APPLIED FULL BRAKES; WHICH TURNED THE ACFT SHARPLY TO THE R. THE ACFT CAME TO REST WITH THE NOSEWHEEL 2-3 INCHES OFF THE RWY EDGE. THERE WAS NO DAMAGE TO THE ACFT OR ANY ARPT PROPERTY. MAINT SUBSEQUENTLY DETERMINED THAT 1 OF THE 4 BRAKE PADS ON THE L MAIN GEAR WAS MISALIGNED; CAUSING ONLY THE MISALIGNED PAD TO MAKE CONTACT WITH THE DISC; WHILE ALL 4 PADS WERE IN CONTACT WITH THE DISK ON THE R BRAKE. THIS DISPARITY IN BRAKING AUTH; THEREFORE; BECAME MORE PRONOUNCED AS MORE PRESSURE WAS APPLIED. UNFORTUNATELY; THE LONG RWY AT ZZZ WAS CLOSED; AND I WAS OPERATING ON THE SHORT RWY; AND HAD NO CHOICE BUT TO TURN THE ACFT SIDEWAYS TO BRING IT TO A STOP. CONTRIBUTING FACTORS: 1) I HAVE NEVER EXPERIENCED AN ASYMMETRIC BRAKE FAILURE; AND MAY NOT HAVE REACTED QUICKLY ENOUGH TO STOP THE ACFT ON THE CTRLINE; IF IT WAS POSSIBLE AT ALL. 2) I HAD BEEN AT WORK SINCE XA00; SO FATIGUE MAY HAVE BEEN A FACTOR. 3) ALTHOUGH THIS WAS A MECHANICAL PROB; I HAVE NO DOUBT I WOULD HAVE BEEN ABLE TO STOP PROPERLY HAD THE LONGER RWY BEEN AVAILABLE IN ZZZ. CORRECTIVE ACTIONS: I BELIEVE THAT IF THE BRAKE ASSEMBLIES ARE REMOVED FOR ANY REASON; THE BRAKES SHOULD BE TESTED BY CONDUCTING A TEST FLT; OR BY PERFORMING A HIGH SPD TAXI TEST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT MAINT INFORMED HIM ONE OF THE BRAKE DISC PADS ON THE LEFT MAIN GEAR BRAKE ASSEMBLY WAS NOT SEATED PROPERLY IN THE DISC'S ROTOR. AS A RESULT; THIS CREATED A WIDER GAP AT THE MISALIGNED PAD THAN NORMALLY EXISTS WHEN ALL FOUR PADS ARE PROPERLY SEATED AGAINST THE DISC (ROTOR) FACE SURFACE. AS HE WAS APPLYING GREATER PEDAL BRAKING FORCE; THE MISALIGNED PAD ON THE LEFT BRAKE PREVENTED NORMAL BRAKING ACTION ON THE BRAKE DISC. THIS LOWER BRAKING EFFECT ON THE LEFT BRAKE ALLOWED THE RIGHT BRAKE WHICH WAS WORKING FINE; TO BECOME DOMINANT CAUSING THE ACFT TO TURN SHARPLY TO THE RIGHT. REPORTER DID NOT KNOW IF THE MM PROCEDURE FOR THE BRAKE CHANGE REQUIRED AT LEAST A MINIMUM TAXI BRAKE TEST.

Data retrieved from NASA's ASRS site as of January 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.