Thirty Northrop Corp. managers were removed from their positions for falsifying test results of guidance components in the MX and cruise missile programs, a senior company executive told a congressional panel yesterday.

But Frank W. Lynch, vice chairman of the Northrop board, denied charges by congressional investigators that portions of the MX guidance system manufactured by the Los Angeles-based company were inaccurate.

President Reagan has called the $19 billion MX intercontinental ballistic missile program the centerpiece of efforts to modernize U.S. strategic forces.

Lynch told the House Energy and Commerce subcommittee on investigations that because of unacceptable "lapses and errors of judgment" the company moved about 30 key people "out of their management responsibilities," including executives in the electronics division in Los Angeles and the Northrop plant in Pomona, Calif., working on the inertial measurement unit in the MX guidance system.

Subcommittee Chairman John D. Dingell (D-Mich.) cited among management problems the alleged MX mischarges on labor and costs, false certification of MX tests and parts and provision of bonuses for executives who mismanaged the missile program.

Dingell quoted former company auditor T.F. Sheilke as saying that "our internal audit reports end up being buried indefinitely with no solution to the problems."

Shielke, who gave the subcommittee many company documents and was scheduled to testify yesterday, disappeared last Thursday and said he would not appear in public without bodyguards, subcommittee sources said.

Lynch said he had no direct knowledge of the Shielke case.

Lynch said that since June, Northrop has tripled its auditors and cut its MX guidance system backlog from 23 to a dozen.

But he acknowledged that Northrop had failed to perform adequate tests on cables in the air-launched cruise missile.

Dingell charged that "because of the falsifications, the Air Force is now uncertain about the reliability of 1,900 cruise missiles."

Lynch acknowledged that Northrop bought parts of uncertain quality, and that irregular bookkeeping procedures made it impossible to determine if those parts went into MX missiles.

The Justice Department has launched 11 investigations of Northrop's MX and cruise missile contracts.

Because of Northrop delays, Dingell said, only 17 of 27 MX missiles at Warren Air Force Base in Wyoming are on alert. "That means 90 to 100 deployed warheads are not targeted because of Northrop's failures," he said.