Eastern Air Lines Inc. has continued to falsify airplane maintenance records, possibly jeopardizing the safety of passengers to avoid time-consuming repairs, according to allegations contained in a confidential document unsealed yesterday.

The charges, filed in an affidavit used to justify a raid on Eastern's Miami headquarters, were immediately branded as "outrageous" and "ill-founded" by Eastern, which had fought to keep them from being made public. But disclosure of the allegations came as a major blow to the carrier as it attempts to win back passengers and rebuild itself after a long, damaging strike and nearly two years in federal bankruptcy court.

Eastern said the allegations were part of a "headline-hunting expedition" by the office of U.S. Attorney Andrew J. Maloney of the Eastern District of New York. Maloney's office has been conducting a long-running grand jury investigation that resulted in the indictment of Eastern and nine former and present employees last July on similar charges.

The document was unsealed as a result of a decision by a three-judge panel of the U.S. Court of Appeals in Manhattan, who agreed with U.S. District Judge I. Leo Glasser of Brooklyn that there was no reason to keep the allegations from the public.

Although the allegations in the document are similar to those contained in the indictments last July, what is new is the assertion that the abuses have continued as recently as last month. The July indictment focused on incidents that occurred before a strike by the International Association of Machinists in March 1989. Anthony P. Valenti, a criminal investigator in the U.S. Attorney's Office, said his continuing investigation and interviews with more than 90 former and present Eastern employees "has determined that from approximately January 1987 through early November 1990, Eastern management personnel employed at Hartsfield Airport in Atlanta and elsewhere engaged in the practice of falsifying {Federal Aviation Administration} required maintenance records in order to minimize or avoid costly flight delays or cancellations of Eastern flights."

The affidavit cited information from 13 confidential informants.

According to these informants, Eastern is "routinely falsifying" maintenance records at its principal hub of operations in Atlanta and in Miami where the airline is headquartered, the affidavit said.

Eastern said that general allegations are hard to dispute but it offered point-by-point rebuttals of some of the specific allegations. In one case, two mechanics in Miami said they were assigned to move a damaged engine from the tail to the wing of an aircraft instead of removing it.

Eastern's new president, Robert L. Gould, denied that the engine needed to be removed. It was moved, he said, as an extra safety precaution after a similar engine on the tail of another airline's aircraft blew apart, causing a major accident. The Eastern aircraft engine was moved from the tail to the wing, where it would do less damage in the event it failed. Under both the FAA's and the engine manufacturer's criteria, the engine could have stayed where it was, he said.

Shugrue and Gould said the FAA has investigated many of the allegations contained in the affidavit without finding cause for action.

The FAA said yesterday it already has in place "a program of heightened surveillance over Eastern Air Lines... . "