A RWY EXCURSION RESULTING IN ACFT DAMAGE AFTER A FULL STOP SHORT FIELD LNDG AND SUBSEQUENT TKOF ATTEMPT IN THE REMAINING INADEQUATE RWY DISTANCE.

Narrative

I WAS SITTING IN THE L SEAT. I POSSESS A PVT PLT'S LICENSE AND THE PURPOSE OF THIS FLT WAS TO BE A FINAL STAGE CHK; PRIOR TO CHK RIDE FOR A MULTI-ENG ADD-ON TO MY PVT PLT'S LICENSE. WE HAD JUST DONE A SHORT FIELD LNDG TO A COMPLETE STOP. THE ROLLOUT WAS LONGER THAN IS DESIRABLE FOR A SHORT FIELD LNDG. I LET THE AIRPLANE ROLL OUT LONGER BECAUSE; IN ADDITION TO BEING A LITTLE NERVOUS ABOUT THE LIGHT MIST ON THE RWY; MY R BRAKE PEDAL WAS A LITTLE SOFTER THAN THE L AND I WAS CONCERNED ABOUT APPLYING EQUAL AND CONSISTENT BRAKING. WE DID COME TO A COMPLETE STOP; BUT I AM NOT EXACTLY SURE HOW FAR DOWN THE RWY WE WERE -- JUST SHY OF EITHER THE TXWY OR THE ACTUAL RWY 23/5 WHERE IT CROSSES OUR RWY 28R/10L. THE INTENT AFTER A COMPLETE STOP WAS TO PERFORM A SHORT FIELD TKOF. AFTER STOPPING; WE HELD THE BRAKES AND ADVANCED THE THROTTLES; RELEASING THE BRAKES AFTER VERIFYING WE HAD 2 ENGS. AS WE WERE ACCELERATING; IN ADDITION TO WATCHING DOWN THE RWY; I WAS WATCHING OUR AIRSPD AND SAW THE INDICATOR COME ALIVE AND MADE THE NORMAL CALLOUT 'AIRSPD ALIVE.' CONTINUING DOWN THE RWY AND SEEING THE END APCHING FASTER THAN WE WERE ACCELERATING; AND SEEING WE WERE STILL BELOW VMC (MINIMUM CTL SPD); I CALLED OUT 'ABORT;' RETARDED THE THROTTLES; AND APPLIED FULL BRAKES. I AGAIN HAD SOME TROUBLE WITH THE R BRAKE; BUT I TRIED TO CTL IT AS MUCH AS POSSIBLE. THE INSTRUCTOR; I BELIEVE; WAS ON THE BRAKES AS WELL. WE BEGAN TO SKID STRAIGHT AHEAD; WHICH I BELIEVE WAS POSSIBLY A MIX OF SKID AND HYDROPLANE. THE PLANE REMAINED ON THE RWY CTRLINE AND WE CAME TO A COMPLETE STOP APPROX 25-30 FT BEYOND THE RWY IN THE DIRT. BOTH MAIN WHEELS WERE FLAT WITH HOLES WORN THROUGH THEM. THE R PROP TIPS WERE BENT; HAVING STRUCK THE GND JUST BEYOND THE END OF THE RWY. THERE WERE MARKS ON THE GND TO VERIFY THIS. BOTH CREW MEMBERS WALKED AWAY WITHOUT INJURY. A CONTRIBUTING FACTOR MAY HAVE BEEN THE POS OF THE FLAPS FOR TKOF. AFTER SHUTTING EVERYTHING DOWN AND WALKING AROUND THE PLANE; I NOTICED THE FLAPS IN A DOWN POS. RAISING THE FLAPS AFTER TOUCHDOWN IS THE NORM AS IS RECHKING THEIR POS PRIOR TO TKOF. THE FLAPS MAY HAVE BEEN UNINTENTIONALLY PUSHED INTO THE DOWN POS DURING THE CHAOTIC MOMENTS AFTER EXCEEDING THE RWY AND PRIOR TO SHUTDOWN. UNFORTUNATELY; I HAVE NO SPECIFIC RECOLLECTION OF RAISING OR LOWERING THE FLAPS DURING THE PRECEDING LNDG; TKOF ATTEMPT; OR AFTER EXCEEDING THE RWY. HOWEVER; THE ACCELERATION DID NOT NECESSARY FEEL SLOWER THAN NORMAL AS ONE MIGHT EXPECT SECONDARY TO EXCESS DRAG CREATED BY EXTENDED FLAPS. I THOUGHT ABOUT QUESTIONING THE INSTRUCTOR AFTER LNDG BUT REMAINED SILENT; THINKING TO MYSELF 'THE INSTRUCTOR KNOWS BEST; HE'S BEEN IN THIS POS BEFORE.' I SHOULD HAVE USED PROPER CRM SKILLS; SPOKEN UP AND QUESTIONED THE 'GO' DECISION. HAVING REPLAYED THE EVENT OVER IN MY HEAD; I BELIEVE THE ABORT DECISION WAS THE CORRECT ACTION.