The engine of a news helicopter that crashed into a rustic part of the Pine Barrens last month killing its two crew members showed no difficulties that would have prevented it from powering the aircraft, according to a federal aviation report released Wednesday. The helicopter was being flown for 6ABC Philadelphia when it crashed after dark on Dec. 19., slamming into the Wharton State Forest in Burlington County. The pilot, 67-year-old Monroe Smith, and the photographer, 45-year-old Christopher Dougherty, were killed in the crash. The men were both residents of Montgomery County, Pennsylvania,…