Federal Aviation Administration chief Langhorne Bond went on the offensive in Congress yesterday in an attempt to clear his agency of charges that it has been unsportsmanlike in a multi-million-dollar contest with the British over developing an advanced landing guidance system.

"I hope it will be apparent that the allegations against us have all the substance of smoke," Bond told the House Government Operations Subcommittee on Transportation in the second day of continuing hearings on the issue.

Bond insisted that the $100 million development of the U.S.-favored landing system has been open, as it was supposed to be, that the British government has received all the data it has sought, and that tests of the competing systems are being conducted as Bond promised in an earlier appearance before another congressional subcommittee.

Bond also attacked a registered lobbyist for the Plessy Corp., the British manufacturer of the British system, and charged that his lobbying was subverting an olderly international process by which the advanced landing system will be chosen.

The final selection of the British or American system is scheduled to be made by the International Civil Aviation Organization (ICAO) in April. The hope is that the designation of one system as the international standard would preclude a long-term battle among competing systems and would save everybody money in the long term.

Both British and American interests have told The Washington Post that there is no clear economic advantage for either country: The Americans would be able to manufacture and sell the British system; the British would be able to manufacture and sell the American system.

The central question, then, is which system operates better. The aviation world is interested in an improved landing guidance system to replace the Instrument Landing Systems (ILS) now in use worldwide. ILS units can be used only on runways located in fairly level terrain and permit only straight-in approaches.

The proposed new systems would permit precision guidance for aircraft aproaching on curved or irregular terrain.

Both the Americans and the British have spent years in development programs. But much of the actual data on which an international decision was to be made has been developed from computer simulations rather than actual flight tests.

It is on that point - the validity of the computer - tests - that Plessey lobbyist Michael L. Lehrman has conducted an active campaign against the FAA-backed system.

Lehraman has contacted most of the aviation writers in town, countless members of Congress, the White House and many others in his campaign. His message - always buttressed with pounds of documents - is that the FAA has not cooperated as it should and that the British system is better.

British government representatives have told The Post that since Bond took over as FAA administrator last spring, they have received everything they asked for. But they also continue to question whether the U. S. system is as safe as it should be.Bond insisted yesterday the U. S. system is better.

Bond also said he is tired of fighting a war on two fronts. "We have done to the letter what we were requested to do by the British government, he said. "...but I have a great deal of difficulty dealing with this second level (the lobbying campaign)."

Lehraman, a short, intense man with a Harvard masters in business administration, stood in the back of the packed hearing room yesterday and smiled throughout.

"I believe Bond is an able man in a difficult position," he told a reporter during a break. Asked how much he was receiving for his work from Plessey, he said:

"I get 5,000 pounds (about $10,000) a month, up to 1,000 pounds (about $2,000) a month in expenses," he said. He paused, then said, "I earn every penny of it."