A single-engine airplane clipped two 230-kilovolt power lines Saturday while approaching Montgomery Field to land. The incident occurred about 4:30 p.m. in the area of Kearny Villa Road and Aero Drive, said Elizabeth Abbott, a San Diego Gas & Electric spokeswoman. The plane landed safely and no one was injured. The wires were knocked down, but there were no reports of power failure and traffic was not disrupted. Abbott said SDG&E; customers may have experienced a "surge in power," resulting in dimming lights and blinking televisions, but there was no complete power failure.