The House ethics committee voted yesterday to begin a preliminary inquiry into the 23 free airplane trips that Rep. Dan Daniel (D-Va.) accepted from Beech Aircraft Corp.

Rep. Julian C. Dixon (D-Calif.), chairman of the Committee on Standards of Official Conduct, announced the investigation shortly after a closed-door committee meeting and stressed that the action "does not amount to any formal charges at this time."

Dixon's brief, four-sentence statement said, "The committee staff has been instructed to conduct the inquiry . . .and report to the committee results of its findings, including recommendations."

Daniel, 71, a senior member of the House Armed Services Committee who had pressed for purchases of Beech aircraft, said later in a statement that he had been notified of the committee's action. "I will cooperate fully with the committee in resolving any remaining issues concerning the flights for which I have made restitution," he said.

On Tuesday, Daniel said he had accepted 23 free flights from Beech between 1983 and 1985 and had not reported the trips as gifts. During that time, Daniel was urging Congress to buy 24 Beech C12 aircraft for the Pentagon. He apologized in a floor speech, saying he had misunderstood House rules, and announced that he had sent Beech a check for $1,127 to pay for the rides.

Daniel has said in interviews that there was no conflict of interest involved, and that the flights did not influence his support for the Beech aircraft, which he had grown to like while he was an executive of Dan River Mills, a textile company in southern Virginia.

House conflict-of-interest rules forbid members from accepting a total of $100 or more in gifts annually from any individual or corporation with any legislation before Congress. The rules also require the disclosure of more than $250 in gifts. The free rides were not listed on his disclosure form, and Daniel amended the documents this week to report them.

Page Avjet, the Washington distributor for Beech, provided the free flights for Daniel, and Beech paid for them. Page Avjet also provided a free flight to Aiken, S.C., for Sen. Strom Thurmond (R-S.C.) and his family last May. Thurmond said he did not believe the action violated any Senate ethics rules.