"Some of the measures I have talked about today will be unpopular," said Langhorne McCook Bond, "but I can't help that."

That was last March, when the head of the Federal Aviation Administration was outlining drastic new steps he proposed to make aviation safer.

If Bond was unpopular with the aviation industry in March, he assured himself of undying enmity yesterday when he grounded the controversial DC10 jetliner until further notice.

In the often complex and time-consuming field of federal regulation, Bond fired this one right over the plate without a windup.

The consequences are large. McDonnell Douglas, the builder, will have to spend untold amounts to assure that its DC10 is safe. The airlines stand to lose money by removing the DC10 from their fleets. Passengers face inconveniences, reroutings and hassles over seating because of Bond's decision.

Since becoming President Carter's FAA chief in May 1977, Bond has been making waves - tightening safety rules, shaking up his bureaucracy with reassignments, harping about safety in the skies.

But he didn't become really visible until last fall after the midair collision over San Diego that took 144 lives. Bond threw another hard one - he said part of the blame belonged to FAA traffic controllers.

As explained in his talk last March to the National Aviation Club, Bond sees his duty as "not just to the controllers, not just to the pilots, not just to the operators or airlines and airports. . . . It is to all these groups and to another group more important than any of them - the American public."

Bond, 42, has seen the situation from all sides. He was born in Shanghai, China, where his father was posted as a vice president of Pan American Airways.He has a private pilot's license, although he doesn't fly much now, associates say.

He has a law degree from the University of Virginia and did postgraduate work in aviation law at McGill University in Canada.

Bond spent several years in Washington in the late 1960s at the departments of Commerce and Transportation, then returned here after a four-year tour as head of the Illinois department of transportation.

In Springfield, as in Washington now, Bond is remembered as an administrator who delegated authority, reshaped bureaucracies and said what was on his mind.

"He wasn't into politics," said a former associate in Illinois, "but he knew when to zig and when to zag." CAPTION: Picture, Langhorne Bond sees a duty to a "group more important than any . . . the American public." By Joel Richardson - The Washington Post