Vera Simons, the McLean balloonist who failed last fall in an attempt to make the first nonstop balloon crossing of the United States, could lose her balloon pilot's license for violating federal regulations during the flight, according to the Federal Aviation Administration.

FAA spokesman Neal Callahan said yesterday that investigators from the agency will meet with Simons before deciding whether her license should be suspended for 270 days.

Simons got a letter from the FAA last week accusing her of operating the ballon DaVinci Rrans-America in a manner that was "careless so as to endanger the life and property of others."

The FAA charged in the letter that Simons violated federal regulations by flying the balloon without proper instrumentation, failing to obtain an air-worthiness certificate for the craft and entering "controlled airspace" near airports without permission.

Simons, who suffered a broken leg when the balloon crash-landed in Ohio last October and who is still in a cast, said yesterday she "doesn't care to respond" to the FAA charges until she meets with federal investigators.

But yesterday she defended her behavior and that of her three-man crew when the balloon was forced down at night by a thunderstorm.

"I remember standing on the edge of the gondola, watching the ground below. We saw a very large dark area near a road and guessed it was a field. It was a safe and reasonable place to come down" she said.

The gondola of the DaVinci Trans-America, according to FAA records, made earlier flights sponsored by the federal government to gather information about pollution, radiation and ozone levels in the atmosphere.

Balloon crew member Rudolf J. Engleman , who was aboard the flight last year as well as the earlier flights in the same gondola, has charged that the FAA's mention of failure to obtain an airworthiness certificate is "pretty darm irrelevant."

He has questioned why the FAA failed to bring up the matter during the earlier flights when the government was a sponsor.

The DaVinci flight, was sponsored by the Seven-Up Company and several other major corporations. The balloon, which lifted off in Tillamook, Ore., and was aloft for 133 hours, set a record for the longest overland balloon flight.