THE ACFT COLLIDED WITH A POWER LINE AND NOSED OVER DURING AN ATTEMPT TO RECOVER FROM A SIMULATED FORCED LANDING. THE CFIREPORTEDLY 'CLEARED' THE ENGINE DURING THE APPROACH BUT WHEN SHE TOOK OVER AND ADDED POWER TO CLIMB SHE CLAIMED THE ENGINE DID NOT FULLY RESPOND. SHE WAS UNABLE TO CLEAR A POWER LINE, WHICH HAD REMAINED UNSEEN ON THE APPROACH, AND THE POWERLINES SLIGHT CONTACT WITH THE LANDING GEAR 'TRIPPED' THE ACFT INTO A 'HEAVY' LANDING WHICH COLLAPSED THE NOSE GEAR AND THE ACFT NOSED OVER. THE ACFT ENGINE HAD JUST BEEN ADJUSTED TO A LOWER IDLE SPEED PRIOR TO THIS FLT PER THE CFIS REQUEST. THE MECHANIC SAID THE ENGINE WAS 'WARM' DURING THE IDLE ADJUSTMENT. DURING POST ACCIDENT EXAM THE COMPRESSION ON CYLINDERS #1 & #4 WAS VERY WEAK AND THEY WERE STAKED TO GET AN IMPROVEMENT. THE LOWER PLUGS WERE NOTED TO BE COATED WITH BLACK OIL. THE MAGS CHECKED AS NORMAL.