An aide to two former CIA agents accused of supplying explosives and terrorist training to radical Libyan dictator Muammar Qaddafi surrendered yesterday to authorities at Dulles International Airport.

The aide, Douglas M. Schlacter of Fairfax, was indicted by a federal grand jury here in August for allegedly coordinating many of the Libyan activities of former agents Edwin P. Wilson and Francis E. Terpil.

Schlacter was charged with overseeing the shipment of explosives to Libya and the manufacture of explosive devices in that country, and with supervising activities of current and former American military and special forces soldiers enlisted to train Libyan recruits.

Schlacter has been operating an air freight service in Bujumbura, the capital of Burundi on the northern shore of Lake Tanganyika in central Africa. According to the indictment, Schlacter allegedly served as the "country manager" for terrorist training and supply operations under an April, 1976, contract involving Wilson, Terpil and Libyan officials.

Wilson and Terpil were indicted in April, 1980, by a federal grand jury here on charges of exporting explosives, delayed-action timers and sensitive night vision equipment to Libya. Wilson is living in Tripoli and Terpil is believed to be in Beirut.

Schlacter reportedly left Burundi early Saturday with a female companion and their baby daughter and was met at London's Heathrow airport by a U.S. marshal and an agent from the Bureau of Alcohol, Tobacco and Firearms, who escorted the three from London.

He was met at Dulles by his attorney, Alvin Askew, and assistant U.S. attorney E. Lawrence Barcella Jr., who has directed the investigation here into Wilson and Terpil's activities. Barcella, Askew and Schlacter have been negotiating the conditions of Schlacter's return for more than a month, according to one law enforcement official familiar with the investigation.

U.S. authorities had been negotiating with Burundian officials for months to try to bring Schlacter back. The United States and Burundi have no extradition treaty. Schlacter apparently left voluntarily, after Burundian authorities told him he was no longer welcome in that country.

Barcella would not say if any plea bargain or other arrangements had been made with Schlacter to ensure his return. If convicted, Schlacter could face more than 25 years in prison.

After a brief hearing at federal district court here in Washington last night, Schlacter was placed in the custody of U.S. marshals until formal arraignment, which is expected today.

Citing security reasons, Barcella declined to say where Schlacter was being held.

In an interview last month with CBS News, Schlacter said he was sure that while he was in Libya he was working for the CIA and said he reported regularly about his activities to CIA officials, including Thomas G. Clines, then an active duty CIA training official and now a private consultant in Northern Virginia. CIA officials have maintained that the agency neither knew nor approved of Wilson's and Terpil's operations in Libya.