Betty Liddle and her husband Bill, a Fredericksburg, Va., pediatrician, had talked many times about what to do in case one of them died. But last Wednesday, when the crash of Air Florida Flight 90 took the doctor's life and the lives of 77 other persons, some cold and unexpected questions accompanied Betty Liddle's sudden widowhood -- What caused the crash, and who should pay for the doctor's tragic death?

In the hours after the accident, while Betty Liddle waited for rescuers to find her husband's body, a friend told her about San Francisco attorney Gerald C. Sterns. Sterns is one of the most prominent members of an elite group of lawyers that specializes in the complex and lucrative practice of filing lawsuits demanding millions of dollars in damages for survivors and victims of air crashes.

Friday morning Betty Liddle called Sterns and he agreed to represent her. But he told her to "sit tight for now" until the painful process of retrieving the dead, and the aircraft debris, was done. That night, rescuers pulled Bill Liddle's body from the Potomac.

In Washington, Chicago, New York and Miami, just days after the crash, the tiny fraternity of aviation crash lawyers such as Gerald Sterns received the first delicate inquiries about the legal consequences of the Air Florida accident. It was one of the inescapable results of such a disaster -- the high-stakes search in the courts to find the blame and assess the cost of sudden death.

At 9:39 last night, what is apparently the first lawsuit to result from the disaster was filed in U.S. District court here on behalf of Katherine W. Erickson of Decatur, Ga., whose husband, James, died in the crash.

The suit, brought as a class action by the Arlington law firm of Lewis, Wilson, Lewis & Jones, seeks damages from Air Florida of $5 million in James Erickson's death and the same amount in the deaths of each of the other 73 persons aboard Flight 90 -- a total of $370 million. The suit alleges that Air Florida failed adequately to remove snow and ice from the aircraft's wings and allowed the plane to fly in hazardous conditions.

Air Florida, 9 years old and growing fast, had never had a fatal accident until its Boeing 737 scraped the northbound span of the 14th Street bridge and plunged into the Potomac River. The airline carries a $250 million liability insurance policy, underwritten at Lloyd's of London. The policy covers bodily injury and property damage, according to records at the Civil Aeronautics Board in Washington. The jet aircraft alone was insured for $12 million.

Lawyers interviewed last week predicted that the claims for damages would focus on Air Florida and possibly the maintenance teams that were charged with de-icing the aircraft before takeoff. Investigators have said that 43 minutes elapsed between the airplane's last de-icing and takeoff. A Braniff Airlines pilot reportedly has told investigators he saw excessive snow on the aircraft's fuselage, which could drag down the airplane.

Damage awards in such cases, usually made after a jury has heard evidence, vary depending on the age of the victim, education, occupation, marital status and, in particular, whether the victim had dependents, such as a wife, children or parents, at the time of death. The basic question to be resolved is what a victim's life would have been worth if he or she had lived.

For example, after the crash of Trans World Airlines flight 514 near Upperville, Va., in December 1974, payments ranged from $1,000 to relatives of a 5-year-old boy to $950,000, which was awarded to nine orphaned brothers and sisters. According to public records, TWA and the FAA, which shared the cost of damage awards in the flight 514 crash, paid $8.3 million in lawsuit settlements and jury verdicts to families of half of the 92 persons killed in that accident. TWA has refused to release information on the remainder of the settlements.

Such "wrongful death" actions, however, will not be limited to the passengers on the ill-fated Air Florida jetliner. Relatives of two motorists thrown into the river after the 737 collided with their cars, and two others who died of injuries suffered on the bridge, also may have damage claims against Air Florida or any others whose negligence contributed to the accident.

Adding to the litigation would be legal actions brought by survivors, both from the aircraft and on the bridge, for injuries they suffered. And the D.C. government, which owns the 14th Street bridge, could sue for the cost of repairs, lawyers said.

Who will be the defendants in the litigation, and where they will be sued, are crucial questions to lawyers on both sides of the imminent cases.

"Looks to me like a routine case," said Chicago lawyer John J. Kennelly, the dean of the nations's air disaster lawyers. "The aircraft took off in bad weather . . . unless the airline can show some specific latent defect in the airplane, they're stuck," said Kennelly, who is chairman of the American Bar Association's aviation section.

Kennelly said that the day after the crash, two Florida lawyers representing the estates of victims called for his advice. "I told them they don't have to do anything until the plane is brought out of the water" and investigators retrieve two crucial pieces of equipment from the aircraft -- the flight data and cockpit voice recorders, Kennelly said.

The flight data recorder will reveal, among other things, the Boeing 737's acceleration speed, altitude and direction as it left the runway at Washington's National Airport, according to aviation lawyer Philip Silverman of the Washington law firm of Speiser Krause & Madole, which specializes in air disaster cases. It may reveal, Silverman said, whether the pilot should have aborted his takeoff or whether he had reached the point of no return. The cockpit voice recorder may tell whether in the moments before impact the pilots knew they were in trouble, Silverman said.

Ultimately, the National Transportation Safety Board, which is mandated by Congress to investigate air crashes, will hold public hearings and then make an official finding of the probable cause of the accident and compile a written report on the Air Florida accident. But the NTSB's work will not delay the lawyers in going to court with their lawsuits for the victims' families.

There are legitimate reasons for getting to the courthouse early, the lawyers said, including a chance to monitor closely the crash investigation. In some cases, however, attorneys race to the courthouse because the first person there gets the most publicity -- and publicity brings in more cases.

"That's life," said Chicago attorney Kennelly.

If past experience is the test, the aviation lawyers say, an ugly prelude to filing of any lawsuits will be a ghoulish competition among lawyers who will hunt down families of Air Florida victims, solicit their cases and thus fatten their legal fees.

The aviation lawyers expect that the families of the Air Florida crash victims, and the survivors, soon will be contacted by the airline's insurers about the possibility of settling any claims against Air Florida out of court. Six days after the Chicago DC-10 crash, the insurer for American Airlines sent letters to victims' families. "Money damages can never compensate for the loss of a loved one, but this is the medium recognized by the law for compensating victims in air disasters," the letter said in part. The letter said the airline soon would make a settlement offer to the family and it urged the families not to rush into lawsuits or to agreements for large legal fees.

Large numbers of these disaster lawsuits eventually are resolved with out-of-court settlements, the aviation lawyers said. Half of the awards made after the TWA Flight 514 crash were reached in out-of-court settlements. What bothers the lawyers, they said, is when the insurer moves in early on the families -- before the shock of death has set in -- to minimize their losses.

"They go out and try to bring in cases cheap," said lawyer Kennelly. "Some people fall for it. Some people get in the right hands. Some people get in the wrong hands." The objective, Kennelly said, is to "keep people away from lawyers to save money." There was no indication late last week that families of victims or survivors of the Air Florida crash had received such letters from Air Florida.

The aviation lawyers expect that lawsuits will be filed either in Washington, where the accident occurred, or in Florida, where many of the victims lived. The choice of a "forum" for the litigation can be important, the lawyers said, since some states have limitations on the way the cases are handled and how damages can be collected. And in some states, juries simply tend to be more generous than in others.

"No one would sue in Virginia if they had any brains," said Kennelly. "The verdicts are much lower than they are in Florida or D.C."

Customarily, a lawyer's fee in a wrongful death case amounts to one-third of the total damage award recovered by the family. New York aviation lawyer Lee S. Kreindler said, however, that in airline crash cases, in which expert firms handle cases in bulk and pool their resources, fees can be reduced to 17.5 percent of the family's recovery.

Lawyers for the families aren't the only ones who are preparing for the lawsuits that will follow the Air Florida disaster. At the Justice Department, Mark A. Dombroff, chief of the division that handles all aviation litigation involving the federal government, immediately began following the course of the crash investigation and assessing the potential involvement of his clients -- primarily the Federal Aviation Administration -- if any lawsuits are filed against them.

And the Miami law firm that represents Air Florida -- Greenberg, Traurig, Askew, Hoffman, Lipoff, Quintel & Wolff -- dispatched some its lawyers to the Washington crash site.

"Frankly we do not have a litigation plan yet devised," said Larry J. Hoffman, a partner in the firm. "Our efforts have been directed so far to taking care of the deceased and funeral arrangements."