Narrative:

Weight and balance showed the cg was within range for this 15 min part 91 leg home after a part 135 single pilot charter. Ramp weight was 6020 pounds (mgw 7500 ramp). Normal takeoff distance is 1030 ft with an accelerate/stop of 2190 ft. Runway 33 was the departure runway at a length of 3860 ft of which all was available and used. Position was taken and full power was applied. Both engines came up to take off manifold pressure and RPM. At about 85 KIAS, shortly before rotation, I felt the airplane yaw slightly to the right and noticed the manifold pressure falling off and a split in rpms. I immediately retarded both throttles and applied maximum braking. Feeling only a small deceleration, I applied full back elevator for maximum aerodynamic braking, also continuing full brakes. Directional control was maintained on the centerline. I momentarily let off the brakes and reapplied, hoping for better effect. None was gained. The airplane continued rolling and showing minimal deceleration. I managed to guide the airplane between the runway end lights assessing several hundred ft of grass would assist a full stop. Unfortunately, once the airplane left the runway, the left main wheel dug into soft mud. The left main undercarriage came off, sheared at the connection to the spar, and the airplane slid about 20 ft to a halt. I turned off all system and left the airplane double quick sustaining no injury later, upon walking the runway, I found my tire marks to be 2100 ft long -- 90 ft short of the entire accelerate/stop distance! The FAA has classified this occurrence as an incident. It is my belief that I did everything possible to stop this airplane on a dry runway. All figures quoted above are from the pilot operating handbook. The reality in my situation bore no resemblance to published performance charts. Almost double in fact.

Related reports:

Google
 

Original NASA ASRS Text

Title: PLT OF ATX SMT TWIN ENG ACFT EXPERIENCED AN ENG PWR LOSS DURING THE TKOF ROLL AND ABORTED, RESULTING IN RUNNING OFF THE END OF THE RWY CAUSING DAMAGE TO THE ACFT.

Narrative: WT AND BAL SHOWED THE CG WAS WITHIN RANGE FOR THIS 15 MIN PART 91 LEG HOME AFTER A PART 135 SINGLE PLT CHARTER. RAMP WT WAS 6020 LBS (MGW 7500 RAMP). NORMAL TKOF DISTANCE IS 1030 FT WITH AN ACCELERATE/STOP OF 2190 FT. RWY 33 WAS THE DEP RWY AT A LENGTH OF 3860 FT OF WHICH ALL WAS AVAILABLE AND USED. POS WAS TAKEN AND FULL PWR WAS APPLIED. BOTH ENGS CAME UP TO TAKE OFF MANIFOLD PRESSURE AND RPM. AT ABOUT 85 KIAS, SHORTLY BEFORE ROTATION, I FELT THE AIRPLANE YAW SLIGHTLY TO THE R AND NOTICED THE MANIFOLD PRESSURE FALLING OFF AND A SPLIT IN RPMS. I IMMEDIATELY RETARDED BOTH THROTTLES AND APPLIED MAX BRAKING. FEELING ONLY A SMALL DECELERATION, I APPLIED FULL BACK ELEVATOR FOR MAX AERODYNAMIC BRAKING, ALSO CONTINUING FULL BRAKES. DIRECTIONAL CTL WAS MAINTAINED ON THE CTRLINE. I MOMENTARILY LET OFF THE BRAKES AND REAPPLIED, HOPING FOR BETTER EFFECT. NONE WAS GAINED. THE AIRPLANE CONTINUED ROLLING AND SHOWING MINIMAL DECELERATION. I MANAGED TO GUIDE THE AIRPLANE BTWN THE RWY END LIGHTS ASSESSING SEVERAL HUNDRED FT OF GRASS WOULD ASSIST A FULL STOP. UNFORTUNATELY, ONCE THE AIRPLANE LEFT THE RWY, THE L MAIN WHEEL DUG INTO SOFT MUD. THE L MAIN UNDERCARRIAGE CAME OFF, SHEARED AT THE CONNECTION TO THE SPAR, AND THE AIRPLANE SLID ABOUT 20 FT TO A HALT. I TURNED OFF ALL SYS AND LEFT THE AIRPLANE DOUBLE QUICK SUSTAINING NO INJURY LATER, UPON WALKING THE RWY, I FOUND MY TIRE MARKS TO BE 2100 FT LONG -- 90 FT SHORT OF THE ENTIRE ACCELERATE/STOP DISTANCE! THE FAA HAS CLASSIFIED THIS OCCURRENCE AS AN INCIDENT. IT IS MY BELIEF THAT I DID EVERYTHING POSSIBLE TO STOP THIS AIRPLANE ON A DRY RWY. ALL FIGURES QUOTED ABOVE ARE FROM THE PLT OPERATING HANDBOOK. THE REALITY IN MY SIT BORE NO RESEMBLANCE TO PUBLISHED PERFORMANCE CHARTS. ALMOST DOUBLE IN FACT.

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.