Low-flying planes may be the cause of malfunctions in acluster of traffic lights at a Fairfax County intersection where several fatalities have occurred, claim nearby residents and commuters who travel regularly through the intersection.

Although county police think the claim is far-fetched and say the light at the intersection of Rtes, 50 and 28, south of Dulles Airport functions as it should, the Fairfax County Board of Supervisors apparently is taking the claim seriously.

The board this week decided to ask the Federal Aviation Administration to investigate whether low flying planes possibly could alter the triggering mechanism of the trafic light.

"We may just get the runaround form the FAA," said Fairfax supervisor Marie B. Travesky, who suggested that the FAA be contacted. "But we ought to look into every possibility to stop what's happening at that light."

Five people were killed in two separate accidents at that intersection near Centreville this summer. Two people also were killed there in a fatal accident during 1976, police records show. Forty seven other people have been injured at the intersection in less serious accidents during the past two years.

Police claim speeders are responsible for most of the accidents and extensive testing has shown ther is nothing unusual in the lights' operation. Last week police cracked down on spending and handed out 203 speeding tickets to motorists driving in the vicinity of the traffic lights, said Police Capt. Robert L. Ellis.

Some motorists have complained that the light operates strangely, sometimes jumping from green to red without a warning yellow; other times turning green in four directions at once.

Police say the lights have behaved normally while they were observed for a day at a time and tested in various circumstances, including under water.

In other action, the board directed county staff to look into creating a program that would teach manual job skills to under-educated and low-income teenagers who would in turn use those skills to maintain the property of senior citizens unable to do home repairs themselves.