Lightning spawned by a line of heavy thunderstorms set ablaze at least four houses in the Washington area yesterday evening and struck an airliner as it was pulling into a gate at National Airport, officials reported.

Six ground-service employes gathered around the Piedmont Airlines Boeing 737 were taken to National Hospital for Orthopaedics and Rehabilitation, where officials reported that they were "mostly shook up."

Five of the employes were released, but one was being kept overnight for observation, hospital officials said.

None of the 117 persons aboard the plane -- which arrived from Charlotte, N.C., shortly before 6:40 p.m. -- was reported injured.

Officials said it was unclear late last night whether there was any damage to the plane.

There were also no injuries reported in the house fires -- three in Fairfax County and one in Montgomery County.

Meanwhile, Maryland State Police reported that weather conditions contributed to a four-car chain-reaction collision on the Woodrow Wilson Bridge that killed a 78-year-old Arlington man.

Details about the accident, which occurred at 6:50 p.m., were sketchy, but police said George Benjamin Green of 2716 Nelson St., Arlington, was killed when he was struck by an auto as he tried to push his own car from the roadway after it collided with another vehicle. Green's car was subsequently hit by a second car, police said. Three women also suffered minor injuries in the accident.

Area utility companies said the lightning also caused fuses to blow in power transmission equipment. High winds -- gusting up to 57 miles an hour at the Chesapeake Bay Bridge -- also felled trees and power lines and caused the collapse of several town houses under construction on S. Columbus Street in Alexandria.

The storms, which passed through the area between 5 and 7 p.m., left about 13,000 customers from Springfield to Gaithersburg without power for varying periods. By late last night, about 6,800 remained without electricity.