PA28 PLT TAKES OFF WITH PROP LOCK STILL INSTALLED.

Narrative

UPON SUBSEQUENT INVESTIGATION IT APPEARED I DID NOT TAKE OFF THE PROP LOCK ON PREFLT. I DID A THOROUGH PREFLT WALKAROUND AND INSPECTION TWICE AND MISSED THE PROP LOCK. STARTED ENG (NORMAL); DID RUN-UP (NORMAL); AND WAS CLRED FOR TKOF. ROTATED AT AROUND 50-100 FT; NOTICED THE PROP LOCK AND REQUESTED TO LAND AND WAS CLRED TO LAND ON INTERSECTING RWY BY TWR. LNDG WAS NORMAL AND FLT OPS WERE NORMAL. PROCEEDED TO TXWY AND REQUESTED AUTH TO CHK ACFT. UPON TERMINATION OF ENG OP; THE PROP LOCK CAME OFF AND LEFT LITTLE DAMAGE TO THE PROP. REQUESTED TAXI CLRNC BACK TO RAMP AND COMMENCED NORMAL TAXI TO THE RAMP. IN HINDSIGHT; MY NORMAL ROUTINE OF PREFLT WAS ALTERED CAUSING THE MISSED PROP LOCK. CONTRIBUTING TO THIS IS THAT THE OTHER ACFT I TRADITIONALLY FLY MORE OFTEN DO NOT HAVE PROP LOCKS. USUALLY I FLY THIS ACFT AND IT DOES NOT HAVE A PROP LOCK BECAUSE IT IS HANGARED. IN RETROSPECT; I HAVE LEARNED A LOT ABOUT MYSELF AND HOW AVIATION IS DYNAMICALLY DIFFERENT IN EVERY SIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE PROP LOCK WAS SIMILAR TO A BICYCLE LOCK IN THAT IT WAS A CABLE WITH THE ENDS HAVING A KEY LOCK ATTACHED. IT WAS HARD TO BELIEVE IT WAS NOT NOTICED ON PREFLT AND THAT HE DID NOT NOTICE IT UNTIL AFTER TKOF.