A PIPER PA32 EXPERIENCED A R MAIN LNDG GEAR FIRE PRIOR TO TKOF.

Narrative

I PICKED UP 4 PAX FROM A FLT COMING INTO MEM SATURDAY NIGHT. I GOT A VFR CLRNC OUT OF MEM BACK TO GLH. I BEGAN TO TAXI FROM THE FBO RAMP WHERE I HAD BEEN PARKED FOR 1 HR. I WAS CLRED TO TAXI TO RWY 36C WITHOUT STOPPING ON TXWY C. I USED RUDDER ONLY WITH NO BRAKING AT 1000 RPM TO TAXI. THE VFR GPS ON BOARD INDICATED APPROX 10 KTS OF GND SPD. THE LENGTH OF RWY 36C IS 8400 FT. I ESTIMATED THAT I TAXIED 8500 FT BEFORE I BROUGHT THE AIRPLANE TO A STOP JUST SHORT OF RWY 36C TO DO THE ENG RUNUP AND CHKLIST. WHILE I WAS DOING THE RUNUP I NOTICED THE FLAMES WERE COMING OUT FROM UNDER THE R WING. I ANNOUNCED THAT WE HAD A FIRE ON BOARD; THAT I WAS SHUTTING THE ENG DOWN; AND THAT THE PAX SHOULD EVAC THE AIRPLANE IMMEDIATELY. I CALLED MEM TWR AND RPTED 'MEM TWR; I HAVE A FIRE ON BOARD THE ACFT. WE ARE EVACING THE AIRPLANE.' I THEN PROCEEDED TO SHUT THE ELECTRICAL SYS OFF AND EVAC MYSELF. I HAD THE PAX STAND CLR OF THE CHEROKEE 6 ON THE W SIDE OF TXWY C. WE WAITED APPROX 2 1/2 MINS FOR THE FIRE TRUCKS TO ARRIVE. THE FIREMEN EXTINGUISHED THE FIRE; AND THE ACFT WAS THEN TOWED BACK TO THE FBO HANGAR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FIRE WAS LOCATED ON THE R MAIN LNDG GEAR. THE ORIGIN OF THE FIRE IS STILL UNDER INVESTIGATION BUT IT IS BELIEVED TO HAVE STARTED IN THE R BRAKE. THE FIRE BURNED THROUGH THE LOWER WING ABOVE THE R MAIN GEAR AND CAUSED STRUCTURAL DAMAGE TO THE WING. THE AIRPLANE HAD JUST COMPLETED ITS ANNUAL CHK; BUT HAD PREVIOUS HISTORY OF BRAKE PROBS. THE RPTR STATED THE AIRPLANE'S FIRST FLT AFTER THE ANNUAL CHK WAS TO MEM AND THE BRAKES OPERATED NORMALLY ON LNDG. THE RPTR WAS ASKED IF DURING THE PREVIOUS PREFLT CHK AT GLH AND PREFLT CHK AT MEM IF ANY HYD LEAK OR SEEPS WERE NOTED. THE RPTR STATED NONE WERE NOTED AND THE GEAR WAS DRY. THE FAA HAS THE INCIDENT UNDER INVESTIGATION.