Transportation Secretary Neil Goldschmidt is expected to propose a 27 percent reduction in the number of big jetliner lights permitted daily at Washington National Airport when he announces his long-awaited airport plan today, according to informed sources.

The plan includes shorter hours of operation and a late-night ban on all flights at the airport, plus the introduction of jumbo jets there. The quota system, which determines who may fly into National, would be changed to permit more short-haul commuter flights and fewer major air-line flights.

An absolute limit would be placed on the number of passengers who use National. That limit would force all airline growth in the Washington area to Dulles International or Baltimore-Washington International airports in about three years.

Some of the plan's elements could be changed in last-minute maneuvering at the Federal Aviation Administration and its parent Department of Transportation, sources said, but its central thrust -- a reduction in large planes and thus in noise -- would remain, they said.

Goldschmidt has said he hopes the plan will end a decade-long debate on the future of the airport and will finally permit major terminal and roadway improvements there.

However, each of the proposed elements of the plan is certain to be controversial with some element of National's constituency, from the thousands of people who want fewer flights along National's Potomac River flight paths to the airlines that prefer National because of its popularity with travelers.

According to the sources, the plan contains these specific elements:

Major airlines would be permited 36 sdcheduled takeoffs or landings per hour between 7 a.m. and 9 p.m., plus 18 between 9 and 9:30 p.m. Today, they are permitted 40 per hour between 7 a.m. and 10 p.m., plus another 21 that are scheduled exactly at 10 p.m.

If the plan is adopted, there would be 27 percent reduction in permitted big jetliner flights from 640 per day to 464.

Short-haul, commuter airlines would receive an increase in hourly flights permitted from 8 to 12 or from 8 to 15, depending on the option selected in the final plan. If 12 slots are allocated to commuters, the increase of four would come from the present quota for big airlines. If 15 are allocated to commuters, four would come from big airlines and three would come from "general aviation," private planes and business jets.

National Airport's so-called perimeter rule, under one option, would be revised to permit nonstop flights between National and cities within 1,000 miles. Today, the perimeter is 650 miles, but seven cities lying beyond that perimeter receive nonstop service.Those cities -- Minneapolis, St. Louis Memphis, Tampa, Orlando, Miami and West Palm Beach -- all lie within 1,000 miles. Other cities that might be expected to receive nonstop service if the perimeter is extended to 1,000 miles would be Ft. Lauderdale, Birmingham, New Orleans and Kansas City. Houston lies just outside the 1,000 mile circle.

Annual passenger traffic would be limited to 18 million annually, a level that could be reached as early as 1982 if present trends continue. More than 15 million passengers -- a record -- already have used National Airport this year; in 1970 the total was about 10 million. So far this year about 3.5 million passengers have used Dulles; about 3.8 million have used BWI.

Debates and lawsuits involving National Airport have tied up its future for years. Local opponents of the airport, most of whom live along the Potomac, have sought rulings that would force all new growth to occur at Dulles. Important politicians, such as Sen. Russell Long (D-La.), chairman of the Senate Finance Committee, have long sought to have the perimeter rule altered so they could receive nonstop service from National to their city -- in Long's case, New Orleans. n

National's main runway is not long enough to support a fully loaded airliner and the fuel it would need to make a transcontinental flight. Therefore, the pressure has been to extend the present 650-mile perimeter and wipe out the special treatment those seven cities have received.

There has also been considerable pressure in the Washington area to preserve the regional nature of National's traffic. As airline deregulation has taken hold, there has been some diversion of short-haul flights from cities in nearby states to the seven cities outside the 650-mile perimeter.

Goldschmidt's solution to that appareently would be to reduce the number of "slots" the major airlines receive at National and give them to the short-haul airlines. That is certain to be fought by the major airlines. If some of those slots came from the general aviation community, it will fight, too.

Slots are required at National because of its limited runways and its popularity. When the weather is bad, only about 60 planes per hour can take off and land there. Major airlines, to maintain their schedules, thus require assurance that they will have those slots.

When weather is clear, National takes all the planes it can, and corporate and private planes usually fill the airport. It is not unusual to have 100 takeoffs or landings an hour at Nationao on a clear day.