A high-ranking Trans World Airlines official said yesterday that he has "no suspicion whatsoever" that TWA security checkers at the Athens airport collaborated with hijackers of TWA Flight 847, who somehow slipped guns and hand grenades aboard the plane.

Federal officials indicated that suspicion about how the hijacking started Friday centers on the probability that the weapons were somehow carried around, not through, the security system, sources said.

U.S. officials have considered as an option a travelers' advisory to bring pressure on the Greek government to improve security at the airport, sources said yesterday.

House Foreign Affairs Committee Chairman Dante B. Fascell (D-Fla.) and Rep. Daniel A. Mica (D-Fla.), international operations subcommittee chairman, wrote Secretary of State George P. Shultz to ask for "an international boycott to and from Greece for and until such time as they are prepared to abide by minimum international standards for airport security."

On Sunday, Michael Clarke, chairman of the British Airline Pilots Association, said a ban on flights to and from Athens by his members is "certainly a possibility, unless things are improved very rapidly."

Capt. Tom Ashwood, vice president of the U.S. Air Line Pilots Association and chairman of an international pilots' committee on airline security, said that such a ban must be considered but that "nothing specifically is on the table at this point." He said his first concern is to recover the passengers and crew members.

John Grimes, TWA's vice president for security, said "it is too early" to say exactly why weapons used as the hijacking started were not detected by Athens airport and Trans World Airlines security. The assessment that TWA employes are not involved is preliminary, he said.

Because of the airport's reputation for sloppy security, TWA and several airlines operating there have set up X-ray and metal detector checks of passengers and carry-on baggage even though passengers pass through similar equipment at an airport-operated checkpoint.

Grimes said the TWA equipment is operated by employes hired by the airline and most recently retrained in April.

Experts said the detectors can be bested, although they usually work well. "There is no real system in this world that is perfect and totally infallible," one expert said, adding that, although detecting tools are excellent, "you still have to depend on the human reaction and the human use of those tools."

Last year, U.S. airlines detected 2,957 firearms and arrested 1,280 persons for carrying firearms or explosives, according to a Federal Aviation Administration report to Congress. Immediately after the TWA hijacking, the FAA ordered beefed-up security at U.S. international airports to guard against "copycat" activity, sources said.

The FAA and TWA have been monitoring security and crew and aircraft performance since the hijacking began. Praise for the crew has been high, from President Reagan down. In a telephone call to TWA President C.E. Meyer Jr., Reagan expressed "deep admiration for the performance and courage of the crew," the White House said.

The captain, John L. Testrake, 57, of Richmond, Mo., is a 32-year TWA veteran who only recently began to choose duty on international routes. At the time of the hijacking, his wife, Phyllis, was reportedly waiting in Athens so they could begin a vacation at the conclusion of his trip.

The first officer, Philip G. Maresca, 42, joined TWA in July 1967. He has an apartment in Salt Lake City but calls New York state home. "He's a very stable guy and an outstanding pilot," said a TWA captain who has flown with him.

The flight engineer is Benjamin C. Zimmerman, 45, of Cascade, Idaho, with TWA since May 1968. An ordained Lutheran minister, he is married, with three children.

His wife, Malvia, told The Idaho Statesman of Boise: "I believe all things are in God's hands. He is the God that died on the cross for my sins. That's pretty neat, knowing this. This makes life easier for me and for my husband. He believes the same way. Death is not a thing to be afraid of."

Zimmerman's father, Elmer, who was 88, died in St. Louis of a heart attack after hearing of the hijacking.

Officials in Washington said they know of no mechanical problem with the hijacked aircraft, a Boeing 727, despite some reports.