Any lingering doubts Congress had about the wisdom and justice of compensating the families of the 290 people killed when a Navy warship shot down an Iranian airliner in the Persian Gulf should have been all but laid to rest by now.

If the lawmakers needed a clincher, they now seem to have it in the form of the preliminary findings by a Navy team that investigated the tragedy. The basic finding is that the tragedy resulted because a tense and inexperienced crew aboard the U.S. frigate Vincennes misinterpreted signals from a sophisticated air-defense radar system.Though these findings have yet to pass through a detailed review process and get formally accepted by military brass, they sound plausible. After all, the Vincennes was on high alert at the time. Iranian fighter planes had been detected operating from the same airfield in Iran as the civilian airbus just a short time earlier, and the Vincennes had just survived its first combat action in the gulf, a fight with three Iranian gunboats.

Even after the preliminary findings are reviewed, certain questions may never be answered. For example:

- Even if human error accounts for the Vincennes' failure to accurately read the aircraft's altitude and speed, why didn't the Iranian airliner respond to repeated warning calls from the U.S. vessel?

- Likewise, why did the Vincennes' communications officers think they heard from the civilian airliner the electronic signals of a transponder associated with fighter jets?

- Despite the tense situation, how could the crew of the Vincennes have made such a blunder after their performance in nine months of pre-deployment training had won them an "outstanding rating" - the highest awarded - in anti-aircraft warfare? Does this situation indicate the need for additional training?

- Though the Vincennes' Aegis air-defense radar system seems to have been working properly, does the U.S. military rely too much on sophisticated electronics gear and too little on direct observation and human judgment?

- Moreover, doesn't Iran bear considerable responsibility for this episode because it operates civilian aircraft in what amounts to a combat zone?

Though some of these questions may mitigate America's responsibility for this tragedy, they do not eliminate it. In light of the findings by the Navy investigators, the question is no longer whether or not America should compensate the families of the downed airliner's passengers, who included the citizens of six other countries besides Iran.

Rather, the questions are simply: How much compensation should be paid? Should it be a flat fee, or should compensation be based on such factors as the age of the victims, the number of their dependents, and the earning ability of the deceased? And how can the U.S. make sure the compensation reaches those for whom it is intended, particularly in hostile Iran?

As the most powerful nation on earth, America should also be the most responsible. In the case at hand, that means making a frank admission of this ghastly blunder and doing whatever is possible to repair the damage even though it is pitifully little compared to the lives that were lost.