A man who was found drunk in his car with the engine’s electricity on, but not the engine itself, can be convicted of drunken driving, the Massachusetts Appeals Court ruled yesterday. The court ruled in the case of Robert S. McGillivary, who appealed his conviction of operating under the influence, fourth offense, arguing, among other things, that when he simply put the key in the ignition and turned it, he was not operating the car. Pointing out that it was the first time the court had seen the issue, the court said the fact that McGillivary had turned the key was enough to allow a jury to convict him. “We conclude that, as matter of law, the evidence that the defendant . . . turned the ignition key — an act which the jury could have found to be the first step in a sequence to set in motion the motive power of the vehicle — was sufficient to permit the jury to conclude that he ‘operated’ the motor vehicle,’’ the court said.