The time has come either to upgrade Washington National Airport or close it entirely to commercial jets.

The Sept. 24 near catastrophe involving an Eastern Airlines shuttle illustrates again how unprepared this airport is for nonroutine but not uncommon circumstances, such as an aborted takeoff. If it had not been for the installation of a 750-foot overrun at the end of the runway last year and, perhaps, the installation of distance-to-go markers on the runway -- both steps prompted in large part by congressional pressure following the Air Florida crash in 1981 -- the shuttle flight might have fallen into the Potomac, causing injuries and fatalities.

While legislators, bureaucrats, businessmen and the airlines have avoided facing the issue, all for very logical (but selfish) reasons, the fact is that the airport is not suitable for the kind of traffic it now accommodates, and the public safety is at risk.

Over the past several years, hearings have been held repeatedly in Congress, including in 1983 before the House Science and Technology sub- committee on transportation, aviation and materials, which I chaired. They leave no doubt that the airport is severely deficient in several areas. The longest runway, and the one most used for jet transportation, is far shorter, at 6,800 feet, than runways at most other major U.S. airports. While under ideal conditions it may be long enough, it is the exceptional -- but, unfortunately, not uncommon -- situations that cause fatalities.

Most pilots will tell you that this main runway and the two collateral shorter runways are simply inadequate; there is little margin for error. National allows no flexibility for aborted takeoffs, icy runways and unpredictable wind conditions. The short runways at the airport were built to handle DC-6s and Constellations, not 727s, 757s and DC-9s.

National's approach patterns are also marginal. The north-south approach down the river requires pilots to maneuver among tall buildings and federal monuments. Extraordinary skill is required to negotiate that approach under optimal conditions. When weather or visibility is impaired, the difficulties are magnified.

The approach has been changed in recent years to move the landing pattern away from buildings in Rosslyn, but the basic situation remains unchanged, and while new landing technologies, such as the microwave landing system, may help to reduce the risks associated with the approach, the airport is a long way from receiving the funding it needs to make the approach patterns safer.

It is time to face the inevitable fact that, in order to keep this airport open, significant, expensive improvements are needed. Most important, the main north-south runway should be lengthened, perhaps by 3,000 feet to the south, and at least one of the other runways should be extended as well. Some will raise environmental concerns related to the wildlife estuary to the south of the airport. But if the airport is to stay open and safe, the runway must be extended. Additionally, funds for major technological improvements affecting takeoffs and landings, some of which are currently on the shelf, must be appropriated.

Some people may fear that such improvements would open National Airport to wide-body aircraft, thereby stealing traffic from Dulles and BWI airports, which are much safer. I disagree. These improvements could be made with assurances to limit or cap airport operations, thereby controlling growth. If control and ownership of National Airport were transferred to a regional authority, as has been recommended by Rep. Frank Wolf of Virginia, such controls could be imposed more quickly than if the FAA and Congress maintain control.

National Airport is very convenient to me, my colleagues in Congress, the bureaucracy and thousands in the business community. It is also important financially to the nation's commercial airlines, which capitalize on its convenience and proximity to downtown.

But it is a substandard airport. We cannot continue to rely exclusively on the skill of airline pilots or air traffic controllers to protect passengers flying in and out of National. But that is precisely what we are doing. Selfish motives of convenience have been allowed to outweigh considerations of safety.

Air transportation is still safer than most other forms of transportation, but the recent spate of airline accidents has created a wariness on the part of the public that the government is not doing enough to keep the skies safe. A decision on the future of National Airport could help reassure the public of the government's commitment to air safety.

But if neither the federal government nor the taxpayers nor bondholders of Virginia are willing to commit the resources to improve the airport, National Airport will remain suitable for general and commuter aviation only. If the public wants a truly safe airport, it would be best served by using Dulles and BWI for commercial jet transportation.