The D.C. City Council put itself on record yesterday against a test of alternative routes for jets leaving National Airport, saying the plan would subject an additional 172,000 District residents to airplane noise and potential danger from accidents.

The action could result in the so-called scatter plan being killed today at a scheduled meeting of the 24-member board of the Washington Metropolitan Council of Governments (COG), if Mayor Marion Barry's representatives on the board follow the direction of the nonbinding resolution approved by the council.

The resolution allied the District government for the first time on the issue with Arlington, Alexandria and Fairfax, which all have opposed the controversial plan. Montgomery and Prince George's county officials support the test.

The action was taken at the council's last legislative session before it goes on recess until September. At the sometimes acrimonious meeting, the council also approved $200,000 in supplemental fiscal 1983 funds for the Washington Convention Center, approved tax exemptions for shared-equity arrangements to help low-income persons buy housing and passed a bill keeping this year's property tax rates the same.

The scatter plan is designed to give relief to some communities along the Potomac by letting pilots turn off the river shortly after takeoff. It would expose about 320,000 more area residents to airplane noise, about half of those in the District, while reducing the noise for others.

Council member H.R. Crawford (D-Ward 7), who is also president of COG, indicated his support for the scatter-plan test, scheduled for September through November. But after the council's action opposing it, Crawford said he would vote against the test if the other three District representatives on the COG board do.

"It would kill the test" if the District votes as a bloc against the proposal, Crawford said. The four D.C. representatives will try to reach a consensus before today's meeting, he said.

The council's other representative on the COG board, Nadine P. Winter (D-Ward 6), said she would vote against the scatter-plan test because of strong opposition by District residents who would be affected.

Pauline A. Schneider, the mayor's director of intergovernmental relations and one of his representatives on the COG board, said yesterday she did not know which way she would vote on the issue but that the council's action would have to be considered.

The council approved $200,000 for the Convention Center, to make up for funds already spent on the center's bid for the 1984 Democratic National Convention, after center officials provided figures showing the money was not available from $1.8 million the city already had authorized for promoting the center in fiscal 1983.

Charlene Drew Jarvis (D-Ward 4), who had questioned the need for the supplemental funding on Monday, recommended approval of the request yesterday after receiving an updated listing of the center's obligations through the year.

Lack of the funds could jeopardize payments to neighborhood groups involved in promotions and to minority contractors at the center, she said. But she said the council would further scrutinize the center's spending during the budgeting process.

The lower income housing plan provides exemptions from deed recordation, transfer and property taxes for home purchases under shared-equity financing agreements with lower income households. Under a shared-equity arrangement, investors combine resources with individuals who get part ownership of a home and pay some rent to the investor-partner.

The plan generally would apply to housing that is currently vacant, said the bill's sponsor, John A. Wilson (D-Ward 2).

Jarvis, chairman of the housing and economic development committee, objected to the bill as lacking enough protections to lower income consumers. She withdrew several proposed amendments after Wilson opposed them as unnecessary, but said she would reintroduce them later.