It was 26 minutes after the plane crashed at Washington National Airport yesterday before the first ambulance left the scene with a load of badly injured people. It was nine more minutes before the second ambulance left, and more than 100 persons still needed immediate medical help.

It was not real. The plane crash did not happen and the realistic-looking wounds on 150 "victims" were the product of make-up fakery, not a disaster. It was the first test ever by National Airport and the area emergency teams of the airport's disaster plan. It will need some tuning.

There were delays in classifying the severity of wounds so victims would get attention on a priority basis. Not everybody on the scene understood the priority system that was being used. As a result, some slightly injured people were taken to area hospitals before others more seriously injured.

An Army National Guard helicopter landed with a load of patients at Georgetown University Hospital. Nineteen minutes after that happened, the hospital received its first call notifying it that "a helicopter had been dispatched."

United Airlines, which provided an airplane as a part of the stage, simultaneously tested its own crash-response procedures. The test was supposed to be triggered when the air traffic control tower called United to notify it about the crash. The call never came.

"This is the reason for running these tests," said J. J. Ruddy, chairman of the Air Line Pilots Association's Airport Committee. "You find out how botched up it can really get, and how you know what you have to improve."

The wonder is that it was not more fouled up. Airport officials have been writing their scenario and coordinating with the myriad of Washington area agencies for months in preparation for yesterday's drill.

Ambulances responded from Arlington, Alexandria, Fairfax County and the District of Columbia. The Army sent helicopters. Firefighters came from Arlington and Alexandria to supplement the airport fire department.

Seven hospitals provided emergency room care - George Washington, Georgetown, the Washington Hospital Center, Arlington, Alexandria, Fairfax County and National Orthopaedic and Rehabilitation.

The plan called for a transportation coordinator at the airport to find out how many patients each hospital could take at a given time and dispatch the ambulances or helicopters accordingly. That part seemed to work fairly smoothly.

The heart of the evacuation system is something called "triage" - the evaluation of wounds of disaster victims so that those hurt worst get the first treatment; those dead are temporarily ignored; those who can talk, wait.

The system used yesterday had members of a "triage team" move through the "wreckage" and attach red, green, yellow or gray cards to each victim. That process appeared to reporters yesterday to move very slowly.

The yellow smoke bomb went off, indicating the start of the drill. The fire trucks came screamng across the airport and were in action within five minutes. Arlington County's ambulances were there within 10 minutes.

The triage team started to work. More ambulances arrived and the assessment process continued. Everybody else waited for the team to do its work. Finally, 18 minutes after the "fire" was out and the victims accessible, the first ambulance left.

Dr. Richard Kelly, a surgeon at National Orthopedic Hospital who said he had battlefield experience, said that "you should have a triage officer - one or two - with 25 guys going behind with bandages and the ambulances behind them." The triage team, Kelly said, should literally run among the living victims, tagging them. Those following would do immediate first aid and the following ambulances would pick up the red first and leave.

It was, of course, a drill yesterday. It was a pleasant day and despite the play-acting of the "victims" there was no real sense of urgency.

It was also a good deal neater than a real crash scene is, where fire and confusion are the rule, where spectators begin to crowd around, and where airport employees come rushing out to help - or to hinder.

Once priorities were established, however, there appeared to be some confusion about whom should be loaded first. Several people with green tags (priority 2) were put on ambulances while those with red tags (priority 1) were left.

Monica Mungold, a Red Cross volunteer and a registered nurse, said after the exercise, "I honestly didn't know about the significance of the tags until quite late. I guess that's one reason why we did this."

One hour after the exercise began, everybody had been cleared from the field and placed on stretchers or (if ambulatory) bused to a first-aid station set up in a hangar. But 50 persons, including many with red tags, were still waiting for ambulances.

That would probably not happen in a real situation, because many more ambulances and helicopters would have been made available than were released for the test yesterday.

Furthermore, the helicopters yesterday were authorized to carry only military personnel. A waiver to that rule would have been immediate in the event of a real disaster, officials said.

There apparently were no traffic problems for the emergency vehicles entering and leaving the airport - but the drill was conducted on Saturday, normally the slowest day there. There are plans to handle traffic and direct emergency equipment during a Friday evening rush hour, for example, but they were not tested.

Inside the airport, large signs told real passengers that the exercise was going on and that the gore at the end of the runway was not real.

When it was declared over, one hour and 45 minutes after it started, airport officials said they had dispatched 86 patients to hospitals. 20 had been taken care of at the airport, and 44 had "died."

"This was the best way to find out what we do right and what we do wrong," said JamesT. Murphy, director of Metropolitan Washington Airports.