The Federal power commission split 2 to 2 yesterday over which of two overland pipeline routes if should recommend to President Carter for the transportation of Alaskan natural gas through Canada to the lower 48 states.

The two routes, one proposed by Alaskan Arctic Gas Pipeline Co. and the other by Alcan Pipeline Co., would carry 25.5 trillion cubic feet of natural gas from the Prudhoe Bay field on Alaska's North Slope.

"Based on today's circumstances, reasonable men can disagree on the right course of action," the commission told Carter.

Thus the commission failed to endorse a Feb. 1 decision by FPC Administrative Law Judge Nahum Litt, who favored the Arctic Gas proposal.

The stalemate means that the President must make the final pipeline decision without clear guidance from FPC.

In recommending that Carter choose one of two overland routes through Canada, the commission said either one would offer lower transportation costs than a proposal by E1 Paso Natural Gas Co. for liquefying the gas on Alaska's south coast and shipping it in tankers to Point Conception, north of San Francisco.

Carter has until Dec. 1 to make his decision. The 1976 Alaskan Natural Gas Transportation Act requires that the President's decision be approved in a joint resolution by Congress within 60 days.

Should one house reject the decision, Carter would make a new recommendateion within 30 days.

The Arctic Gas proposal would carry Alaska and Canadian gas from the Macken Delta in Canada's Northwest territories to Alberta. From Albert it would be shipped in two pipeline to midwestern and western state. Midwestern senators, including Walter F. Mondale (D-Minn.) who is now Vice President, favored the Arctic Gas proposal during hearings last years.

The Alaskan proposal would move only Alaska gas, and is preferred by environmentalists because it avoids the Brook National Wildlife Range in Northern Alaska. The Alcan route parallels trans-Alaska oil pipeline, then turn southward along the existing Alcan highway to Alberta.In the United States, Alcan and Arctic would use the [WORD ILLEGIBLE] pipelines.

Two commissioners - Chairman Richard. Dunham and James G. Watt - commended the 4,800-mile route, which is backed by a consortium headed by Northwest Pipeline Corp.

Commissioners Don. S. Smith and John H. Holloman III recommended the 4,175-mile Arctic Gas route proposed by a consortium of 16 U.S. and Canadian gas pipeline companies.

A fifth commission seat is vacant.

While not favoring the E1 Paso route, the commissiioners said it would be "economically viable" if the President chooses neither overland route.

The Arctic Gas and Alcan routes require approval by the Canadian government. Canada's National Energy Board and a one-member commission created in 1975 will make a recommendation to the Ottawa government later this year.

Prime Minister Pierre Elliott Trudeau said in Washington on this spring, "Canadians want to be as helpful to Americans as we can. It is American gas to American consumers." The Trudeau government acknowledges that before approving an overland pipeline route it must satisfy native claims and resolve a number of environmental and economic issues posed by the pipeline proposals.