The Federal Aviation Administration's airline safety inspection program is based on a simple premise: everyone in the airline industry is honest.

The FAA is not set up to detect quickly criminal acts such as the deliberate falsification of records that a New York grand jury charged Wednesday took place at Eastern Air Lines maintenance bases in 1988 and 1989. Rather, the FAA depends increasingly on airlines and aircraft manufacturers, such as Boeing and McDonnell Douglas, to detect and report problems.

The FAA inspection program is mostly a paperwork operation. Inspectors, working out of 80 offices around the country, concentrate on the voluminous maintenance records that must be kept by all airlines. Among other things, the FAA wants to determine if airlines are replacing or maintaining parts in accordance with schedules set up by the airline with FAA approval. "We are not a criminal agency," said Anthony J. Broderick, the FAA's associate administrator for regulation and certification. "We have to assume the validity of those records."

Hands-on inspections of airliners by FAA inspectors take place, but are secondary to the paperwork inspections. If someone falsifies the records, it is likely to be some time before the normal FAA inspection procedures would detect discrepancies.

For example, the FAA detected the problems at Eastern and turned its findings over to the Justice Department for prosecution only after being tipped by whistle-blowers within Eastern's ranks.

FAA's inspection program has been a favorite whipping boy over the years as budget cuts reduced the number of inspectors at the same time deregulation produced an explosion in airline traffic. The FAA failed to detect problems that later led to some spectacular crashes and near-crashes.

In 1983, when it reached a low of 1,331 inspectors, the FAA was jolted by the 10-fatality crash of an Air Illinois commuter plane. The National Transportation Safety Board reported that Air Illinois had falsified records, and that FAA oversight of the airline had been lax.

In 1985, the FAA began the National Aviation Safety Inspection program, which produced large fines against several major airlines. But well-publicized problems continued, including a near-crash of an Aloha Airlines 737 jet on April 28, 1988, after its top peeled away.

The FAA had given the airline a clean bill of health two months earlier, based on an inspection of maintenance records. But the FAA inspectors did not take a close look at the aircraft, which at the time already was sporting numerous visible cracks in the skin of its fuselage.

Prodded by Congress and public opinion, the FAA has almost doubled its inspection force, with 2,300 inspectors now in place and 2,575 scheduled by the end of the year. Following accidents, highly publicized hit teams are often brought in from other parts of the country to undertake thorough inspections of an entire airline. Administrator James D. Busey also early this year announced a program to promote self-policing by airlines, offering amnesty for rule violations detected in internal audits if the airline reports them and takes corrective action.

Rep. James L. Oberstar (D-Minn.), chairman of the House Public Works and Transportation aviation subcommittee, said the FAA's procedures generally had worked well in the Eastern case, resulting in shutdown of the carrier's Kennedy International Airport maintenance facilities, major fines and a grand jury indictment.

"I think they had to be pushed, but they also recognized that, with the labor troubles, with the financial difficulties, there was a high likelihood the carrier would cut corners, so they stepped up their oversight," he said.

Oberstar said pending legislation "really intensifies the FAA's role, but we don't want to cross over the boundary in making the FAA the maintenance agency for the airline. We want to keep them in the role of an audit agency that keeps the airlines honest."

"Based on the inspection procedures and using the resources they have, it would be difficult to expect the FAA to do more than they did in this particular case," said John E. O'Brien, the Air Line Pilots Association's director of engineering and flight safety. ALPA President Henry A. Duffy said any effective safety program must rely on the airlines and their employees. "Only the people in the airline really know what is going on," O'Brien said.