Keating, Aide to Be Tried Separately : Thrifts: Prosecutors and defense attorneys believe that arrangement will be fairer to Judy J. Wischer, a former president of Lincoln Savings’ parent.

A Superior Court judge agreed Friday to separate the criminal trials of former Lincoln Savings & Loan owner Charles H. Keating Jr. and his onetime top aide, Judy J. Wischer.

Acting on the recommendations of both defense attorneys and the prosecutors, Judge Lance A. Ito ordered that Wischer’s trial follow Keating’s.

William Hodgman, the lead deputy Los Angeles County district attorney prosecuting the case, said his review of the evidence indicated that both defendants could be tried “more fairly” in separate trials and that back-to-back trials would be smoother and quicker than one long one with two juries.

Hodgman also told Ito that he intended to seek dismissal of one of the 21 state securities fraud counts against Keating and Wischer. Hodgman said he wants to streamline the case for the jury.

Keating was chairman and Wischer was president of American Continental Corp., the Phoenix development company that owned Lincoln, based in Irvine.

Wischer’s attorney, Abbe David Lowell, argued that transcripts of grand jury testimony show dozens of statements that could be admitted in evidence against Keating but not against Wischer, making a joint trial unfair to her.

In addition, evidence supplied by two co-defendants who pleaded guilty--former Lincoln presidents Robin S. Symes of Malvern, Ohio, and Ray C. Fidel of Newport Beach--had not yet been turned over to Keating and Wischer. Statements they make about Keating would probably not apply to Wischer and would be “extraordinarily unfair” to use in a joint trial, Lowell said.

Keating’s attorney, Stephen C. Neal, said his client would be ready to stand trial next Friday, the scheduled start of the first criminal proceeding stemming from the nation’s biggest single collapse of a thrift.

The case, though, is not about the failure of Irvine-based Lincoln. It is limited instead to allegations that Keating defrauded 20 small investors in Lincoln’s parent company of $1.83 million.

All together, some 23,000 investors lost more than $250 million after the parent company, American Continental Corp. of Phoenix, filed for bankruptcy on April 13, 1989. Regulators seized Lincoln the next day. The liquidation is expected to cost taxpayers $2.6 billion.

Most of the investors were elderly Lincoln depositors, and many of them pulled their life savings out of insured certificates of deposit at Lincoln to buy the uninsured American Continental bonds. The investors have charged in civil lawsuits that they were victims of bait-and-switch tactics because they were never told that the bonds were risky or that the company was financially troubled.