DV20 PLTS STRIKE A CONE WHILE TAXIING AND CAUSE DAMAGE TO THE ACFT PROP AT BWI.

Narrative

2 DIAMOND DV20-C1 ACFT WERE PARKED ON THE RAMP SUCH THAT THE R WING OF OUR ACFT WAS BLOCKED BY THE L WING OF THE ACFT AHEAD OF US. THE ACFT DID NOT TOUCH EACH OTHER (SINCE THE OTHER ACFT WAS PARKED ABOUT 7 FT AHEAD OF OURS). THE FLT STUDENT I WAS INSTRUCTING AND I COMPLETED THE PREFLT INSPECTION OF OUR ACFT AND ITS SURROUNDINGS. WE NOTED THE POS OF THE OTHER ACFT AND CLBED INTO THE COCKPIT OF OUR ACFT TO WAIT FOR THE OTHER ACFT'S DEP (THEIR L WING; BEING AHEAD OF OUR R WING BLOCKED OUR WAY FORWARD). WE ALSO NOTED THAT NOTHING ELSE BLOCKED OUR WAY. WHEN THE OTHER ACFT MOVED AWAY; WE VISUALLY CLRED; STARTED OUR ENG AND BEGAN TO MOVE FORWARD. WE MOVED JUST A FEW FT WHEN THERE WAS A NOISE AND FLYING DEBRIS. WE IMMEDIATELY SHUT THE ENG DOWN; EXITED THE ACFT AND INSPECTED. WE SAW THAT THERE WAS A DAMAGED ORANGE PARKING CONE ON THE RAMP AND THE PROP OF OUR ACFT WAS DAMAGED. SINCE OUR PREVIOUS INSPECTION OF THE AREA (AS WELL AS THE OBSERVATIONS OF THE OCCUPANTS OF THE OTHER ACFT) HAD NOTED A CLR RAMP AHEAD OF US BEFORE WE CLBED INTO THE COCKPIT OF OUR ACFT; I CONCLUDED THAT A CONE WAS MOVED IN FRONT OF OUR ACFT AFTER WE ENTERED THE COCKPIT IN SUCH A LOCATION THAT THE COWLING BLOCKED OUR VIEW OF IT. I BELIEVE THAT FUTURE OCCURRENCES COULD BE PREVENTED BY TAKING THE FOLLOWING PRECAUTIONS: 1) WHEN PARKING CONE; OR OTHER OBSTACLES; ARE REMOVED FROM AROUND A PARKED ACFT; THEY SHOULD BE REMOVED FROM THE RAMP SO THAT THEY DO NOT POSE A HAZARD TO OTHER ACFT. 2) WHENEVER THE ENG START OR TAXI IS DELAYED FOR ANY REASON; A SECOND WALKAROUND INSPECTION SHOULD BE PERFORMED BEFORE ENG START OR TAXI (TO CATCH ANY CHANGES THAT ARE MADE TO THE RAMP OR THE ACFT; BUT WHICH CANNOT BE OBSERVED FROM THE COCKPIT). 3) ACFT SHOULD BE PARKED SO THAT THEIR WINGS DON'T OVERLAP.