PLT OF A GOV FGT; T38; CAUSED DAMAGE TO A PARKED C170 WHEN HE USED PWR TO TAXI FROM PARKING.

Narrative

WALKAROUND PREFLT NORMAL. CROWDED RAMP BUT NOT ABNORMALLY SO. STARTUP NORMAL. TAXI OUT; REMEMBER USING SLIGHTLY HIGHER PWR TO GET ROLLING (APPROX 70-75%) NOW BELIEVE THIS CAUSED BY SOFT RAMP (HOT DAY OR TWO AT BFI AND ASPHALT SURFACE). EVIDENTLY ANOTHER T38 DEPARTED THE DAY PRIOR AND HAD SIMILAR DIFFICULTIES. LATER LEARNED THAT A C170 WAS PARKED 100-150 FT BEHIND US PERPENDICULAR TO OUR ACFT (THIS IS A TAILDRAGGER). IT WAS CHOCKED BUT NOT TIED DOWN AND PARKED NEXT TO A FENCE. EVIDENTLY THE HIGHER THRUST REQUIRED TO ROLL PRODUCED ENOUGH FORCE TO SWING THE C170'S TAIL INTO THE FENCE DAMAGING THE L HORIZ STABILIZER; VERT STABILIZER AND CTL SURFACES. MY LIST OF CAUSES: C170 PARKED BEHIND A JET EXHAUST AND CHOCKED BUT NOT TIED DOWN. SOFT RAMP NOT CAPABLE OF SUPPORTING OUR HIGH FOOTPRINT LOADS ON A HOT DAY. HIGHER PWR SETTING REQUIRED TO ROLL ACFT. WHO TO BLAME (THERE'S ENOUGH TO GO AROUND). CREW: COULD HAVE ENSURED AREA CLR BEHIND ACFT (BUT 150 FT SEEMS EXCESSIVE). GND CREW: SHOULD NOT HAVE PARKED C170 BEHIND A JET. C170 PLT: SHOULD HAVE TIED DOWN HIS ACFT. FBO/ARPT: MAKE SURE RAMP IS SUFFICIENT TO SUPPORT HVY FOOTPRINT ACFT.