Since a Pan American World Airways jetliner crashed near New Orleans International Airport July 9, 1982, killing 154 persons, 20 fatal domestic-airline accidents have killed 185 passengers, crew members and ground-support employes.

Of those fatalities, 35 involved big-name carriers -- Eastern, Ozark, Pan Am, Republic and United -- and 29 were on the recent Eastern crash in La Paz, Bolivia.

The other 150 died on airlines such as Air Illinois, Cumberland Airlines, Las Vegas Airlines, Provincetown Boston Airlines (PBA), Vieques Air Link, Wings West and, last Monday, Galaxy Airlines, whose only passenger-carrying plane crashed on takeoff from Reno, Nev., killing 68 of 71 persons on board. It was the highest death toll in any U.S. accident since the 1982 New Orleans crash.

Since airline deregulation, the proliferation of small businesses such as Galaxy, flying big planes, and the growth of commuter lines, which have more than doubled their passenger-count since 1978, are forcing the aviation-safety establishment to shift its focus from big to little names. The National Transportation Safety Board and the Federal Aviation Administration find the shift challenging.

FAA Administrator Donald D. Engen said in an interview, "We recognize we are going to have to go in and look very carefully" at small and commuter airlines, "particularly at maintenance figures to make sure we're covering all the bases." Many small airlines do not have their own maintenance departments, and farm it out to others.

A carrier might contract-out maintenance, Engen said, "but I maintain it cannot contract-out its responsibility." FAA's inspectors are assigned to airlines, not to purveyors of maintenance. "We're having some real soul-searching to see how we close that loop," Engen said.

Engen declined to answer questions about the Galaxy accident now under investigation by the safety board. The cause of the accident is unknown, but the investigation has developed questions for the safety board and is finding some answers harder to get than from a major carrier.

Most of Galaxy's maintenance is farmed out, according to investigators.

Rudolf Kapustin, the investigator in charge and a veteran of many accident investigations, said that when the board needs information from a small carrier, "It takes more of our resources to get it and longer to get it" than it would with a major airline.

Kapustin said that Galaxy Airlines has cooperated fully, but that "90 percent of the airline is involved" in supporting the inquiry.

For example, airline president Philip Sheridan personally represents the airline's interests at safety board meetings. Airlines, airplane manufacturers, engine manufacturers and other interested parties are routinely included in board probes, but it is rare that a company president is involved.

Sheridan refused all interviews last week. Bruce Laxalt, a Reno attorney and nephew of Sen. Paul Laxalt (R-Nev.), issued two prepared releases on behalf of Galaxy but declined to answer questions.

Late in the week, a Galaxy pilot, Henry James Whitehouse, was asked to withdraw from one of the investigation's subcommittees because, it had been discovered, he was among those to be questioned.

The day before the 25-year-old Galaxy Lockheed Electra crashed, Whitehouse flew the same plane, without passengers, from Las Vegas to South Lake Tahoe. As he was taking off from Las Vegas, an Eastern Air Lines captain, following the Galaxy flight to the runway, radioed the Las Vegas tower:

"You ought to tell that Lockheed Electra . . . that they ought to look at their No. 1 engine. That thing's smoking a lot and losing some kind of liquid." The Galaxy crew heard the transmission, acknowledged it, asked some questions of the Eastern captain and continued the flight.

Safety board chairman Jim Burnett said that after the plane reached South Lake Tahoe to pick up passengers, "the captain [Whitehouse] did a power check, a maximum runup" on the No. 1 engine, the outboard left-wing engine of the four-engine plane.

However, Burnett said, there is no indication that a mechanic looked at the engine or that maintenance was performed on it between the Las Vegas report and the Reno crash. Other witnesses have told the board that the plane leaked fuel on several occasions.

Nothing so far has tied the smoking engine or leaking fuel directly to the crash.

The crash occurred immediately after takeoff from Reno when the pilot reported "vibration" and said he was attempting to return to the airport. The plane never got higher than 200 feet, the board estimated.

Vibration at low altitude is usually an engine-propeller synchronization problem, and that remains the prime focus for the board.

The plane that crashed probably has been as closely examined by the FAA in the past year as any aircraft. It was used by Democratic presidential candidate Jesse L. Jackson for campaign flights, then given a special inspection at the request of the Secret Service after a rough flight last May. The plane was given a clean bill of health.

"The budget of the United States wouldn't permit" FAA inspectors to ride on every airplane flight, Engen said. However, he said, small big-plane operators and commuter airlines, "Need somebody to look over their shoulder. What we're asking ourselves is if we can do it better, somehow."