A federal judge hinted yesterday that he may dismiss some of the charges on which Dr. Murdock Head, executive director of the Airlie Foundation near Warrenton, Va., is scheduled to stand trial in September.

Head, who started the tax-exempt foundation 16 years ago and it also a George Washington University department chairman, was indicted July 12 for allegedly conspiring to bribe Rep. Daniel Flood (D-Pa.), Flood's former aide Stephen B. Elko, and former representative to Passman (D.-La).

Head was also charged with tax evasion and with giving an illegal gratuity to a now-retired Internal Revenue Service agent.

Judge Oren R. Lewis raised the possibility, during a hearing yesterday in U.S. District Court in Alexandria, that he may dismiss the illegal gratuity charges. These represent five of the 13 counts on which Head was indicted. His trial is scheduled to begin Sept. 10.

Lewis had previously dismissed similar charges against the former IRS agent alleged to have received the illegal gratuity from Head. The IRS agent, Jesse R. Hare, was supposed to have received an illegal $11,000 loan that prosecutors contend was "laundered" to conceal Head's role in arranging it.Lewis dismissed the charge in April, saying that the statute of limitations had expired. Prosecutors have appealed the dismissal to the U.S. Court of Appeals.

Yesterday, Lewis indicated he may dismiss the illegal gratuity charges against Head on similar grounds, telling prosecutors they could then "go to the Court of Appeals on both of them." He scheduled another hearing for next Friday and may announce his ruling then.

During yesterday's 30-minute hearing, Brian P. Gettings, one of Head's attorneys, disclosed some of the key arguments he expects to present to a jury in Head's defense.

He said he would call Head to the witness stand as part of an attempt to damage Elko's credibility in connection with the bribery and conspiracy allegations. Elko was a key witness in the Flood trial, which included similar allegations to those in Head's indictment. Flood's first trial ended in a hung jury and a retrial has been set for Oct. 15.

If Lewis does not dismiss the illegal gratuity counts, Gettings said he plans to argue that the $11,000 loan to the IRS agent did not constitute a crime. Although he did not discuss this contention in detail, Gettings implied he would argue that Head had not arranged the loan to influence Hare's tax audits or Airlie or other enterprises linked with Head.

In response to the tax evasion charges, Gettings pointed to one likely defense argument by asserting that Head was not an officer or stockholder of Raven's Hollow Ltd., a film production firm linked with the Airlie Foundation. Raven's Hollow's finances are central to the tax charges. Prosecutors contend that Head, nonetheless, controlled Raven's Hollow, a profit-making venture.

Gettings is also expected to argue that no tax evasion occurred. CAPTION: Picture, DR. MURDOCK HEAD...charges on illegal gratuity