Investigators say engine failure may be to blame for the fatal crash of a small plane last summer 100 yards from the historic Portland Head Light. Dr. Louis Hanson was unresponsive when he was recovered from the water after his Stinson S108 splashed down on June 24 off Cape Elizabeth. The Sun Journal, says the National Transportation Safety Board found that the lower portion of one of the pistons had fractured, causing metal pieces to enter the engine’s camshaft. The factual report, which didn’t draw any final conclusions, says the airplane was built in 1946 and had its original engine. The NTSB says Hanson told air traffic controllers before crashing that he’d experienced a total power loss and was not going to be able to glide back to shore.