IT IS DECISION TIME for President Carter on future operations in this country of the Concorde, the British-French venture into supersonic transportation. The 16-month trial period authorized by former Transportation Secretray William Coleman runs out this weekend. On the basis of what we have heard about the results of that trial, we think the Concorde ought to be permitted to operate at some American airports under rather strict conditions.

Unfortunately, a major part of the evidence on which the decision in this matter should turn is not available. That is because of the intransigence of the New York Port Authority, which has successfully frustrated tests of the Concorde at Kennedy Airport. The tests at Dulles have been completed and, although the report on them has not been made public, it appears to have material in it that is subject to varying interpretations. The instruments by which sound is measured show that the Concorde makes much more noise than any other commercial aircraft during takeoffs but about the same amount of noise, while landing, as the most noisy ones now in service. But studies of public attitudes suggest that this level of noise, which is highest directly under the takeoff route, is nonetheless acceptable to most people.

We have no doubt that a presidential decision favorable to the Concorde could substantially undermine the broader campaign to reduce aircraft noise. Other manufacturers will cite it when they seek exceptions from noise regulations. And these exceptions must not be granted - either to other aircraft that are now being altered to reduce noise or to other kings of equipment. But the Concorde is a special case for three reason: 1) It is an airplane that met the noise requirements in existence when it went into construction and that cannot be altered to meet those the federal government is now trying to inforce. 2) There are never going to be many Concordes; the production run was 16, and if the British and French have any economic sense, they will build no more of them. 3) The airplane does belong to two friendly governments that made major adjustments in their own airports and accepted a sudden increase in airplane noise not too many years ago when American-made four-engine jets started flying the Atlantic.

Taking all this into consideration, we think the President should clear the existing Concordes for landing in the United States and, at the same time, warn anyone who makes another supersonic plane that it must meet either the noise levels now established for new subsonic planes or a new set of especially designed and stringent standards. A decision by the President to do this much does not guarantee the British and French landing rights at many American airports. Unless the President is prepared to have the federal government preempt all aviation noise restrictions, local airport rules will still apply. In effect, this will give cities an option to accept or reject Concorde service depending on local rules and the manner in which they are enforced. But such a federal policy would not be applied, we would hope, in a way that would permit airport authorities to act as unfairly and arbitrarily as the New York Port Authority has acted in its 16 months of discrimination against the Concorde.

This approach would probably not be wildly hailed in London or Paris because it would not authomatically open up any American airport to the Concorde. But it would avoid the worst alternatives. The Concorde has a limited function - hauling rich, fancy and expense-account people - and needs only limited operating rights. These can be best determined on a city-by-city basis by local authorities. Such limited operating rights will also limit the disturbances caused by an excessively noisy airplane that ought not to have been built.