SMA PLT ALLOWS ACFT TO SLOW TOO SOON ON LNDG. IMPACT CAUSES RWY EXCURSION.

Narrative

DURING LNDG ATTEMPT PLT TRIED TO HOLD ACFT (TRAIL DRAGGER) OFF RWY UNTIL IT WAS BEYOND THE DISPLACED THRESHOLD (1500 FT PAST APCH END OF RWY 31) AND ACFT BECAME TOO SLOW (INADVERTENT) AND DROPPED TO RWY IN FLARED ATTITUDE. AFTER IMPACTING RWY WITH TAIL WHEEL FIRST; MAIN GEAR IMPACTED RWY AND ACFT VEERED TO L AND DEPARTED RWY. ACFT THEN PROCEEDED THROUGH DRY GRASS SECTION ADJACENT TO RWY BEFORE RETURNING TO RWY. DAMAGE TO THE ACFT WAS A BENT TAIL WHEEL SUPPORT SPRING ROD AND A SCUFFED L WING TIP TRAILING EDGE. AFTER MINOR REPAIRS ACFT WAS FLOWN BACK TO GRANTS PASS; OR; WHICH REQUIRED 2 HRS AND SHOWED NO PERFORMANCE DEGRADATION. THE MAJOR CONTRIBUTING FACTOR WAS THE DISPLACED THRESHOLD WHICH SEEMS EXCESSIVE IN VIEW OF TOTAL RWY LENGTH OF 4060. THE DISPLACED THRESHOLD WAS ENACTED FOR NOISE ABATEMENT CONSIDERATIONS. THE LCL PLTS APPARENTLY DISREGARD THE DISPLACED THRESHOLD TO FACILITATE THEIR LNDGS. THIS PLT TAKES FULL RESPONSIBILITY FOR THE INCIDENT SINCE THE ACFT SHOULD NOT HAVE BEEN ALLOWED TO SLOW DURING THE LNDG FLARE TO THE POINT WHERE IT SETTLED TO THE RWY AT TOO STEEP A FLARE ANGLE. CONTRIBUTING ALSO WAS A MOMENTARY LOSS OF RADIO COMS DURING LNDG APCH. IT WAS LATER TRACED TO SQUELCH; BREAK ON VOR PORTION OF NAV/COM RADIO WHICH GENERATED NOISE SUFFICIENT TO OBLITERATE ALL RECEIVE COM SIGNALS (AND INTERCOM SIGNALS).