A New York Air DC9 jetliner struck and killed two deer as it was landing at Dulles International Airport yesterday but touched down safely despite a flat tire and damage to a wing flap, a Federal Aviation Administration spokesman said.

None of the 32 passengers and five crew members aboard Flight 141 was injured in the 9 a.m. incident, said FAA spokesman Dennis Feldman, and most apparently were unaware that anything unusual had taken place.

A spokeswoman for the airline said the plane, which was landing after a flight from LaGuardia Airport in New York, was never in danger of crashing. But Feldman said that such a collision might adversely affect an aircraft under certain conditions, and that the aviation industry has done little or no testing in that regard.

Yesterday's accident was the first in memory involving deer at Dulles, Feldman said, although a sizable deer population thrives on the federally owned airport property. At certain times the number of deer at the airport has become so large that officials have allowed airport employes to hunt some of the animals as a means of population control.

Feldman said that the New York Air flight, scheduled to continue to New Orleans, was landing on runway 19R when the two deer "wandered across the runway" into the jet's path.

One of the plane's main wheel assemblies "made contact" with the deer, he said, blowing out a tire and damaging a wing flap that had been extended for the landing.

Feldman said that planes are equipped to take off and land despite a single flat tire, and a spokeswoman for New York Air said the incident did not endanger any of those on board the plane.

"It did not even appear to the passengers that anything had happened," said airline spokeswoman Diane Sinclitico, who was aboard the flight to attend ceremonies yesterday promoting the airline's newly expanded facilities at Dulles.

Sinclitico said the pilot made no mention of the collision to passengers, and that she did not learn of the incident until later in the day.

"It happened on final approach during landing. He the pilot saw the deer and there was really nothing he could do about it," Sinclitico said. "If somebody wasn't looking out the window and saw the deer, you wouldn't have even known that something was happening."

Details of the damage to the plane were not immediately available, but airline officials said it was flown back to New York for repairs and was expected to be returned to service today.

Feldman said the FAA would investigate the incident to determine whether there is a break in the 8-foot-high chain-link fence surrounding the runways. But he said deer sometimes enter the property by jumping over the fence.

Feldman said it is difficult to assess what dangers large animals on the runways might pose to an airliner taking off or landing.

"That depends on where the strike takes place and how fast the plane is going," he said. "We don't have any information of that nature. It's never been tested."

He said that "the only thing that's been tested is an airborne plane hitting a flock of birds." Birds have been known to crack aircraft windshields or disable planes when caught in an engine.

Feldman said he had "no idea" how many deer are living at Dulles. The rural, wooded areas of Fairfax and Loudoun counties surrounding the airport for years have provided habitat for large numbers of the animals.

In recent years, as many as 500 deer were believed to make their home on the 2,250-acre tract of the Xerox Corp. training center on Rte. 7, a few miles from Dulles. Game officials were forced to consider killing some of the animals there because the burgeoning herd had raised the specter of starvation, disease and accidents.

"If you want to know the truth, Dulles has got a deer problem," said one New York Air official. "There are deer, wild turkeys and all kinds of wildlife out there."

Hunting by the public is prohibited on the airport grounds. But at least some of the deer at Dulles occasionally end up on the dinner tables of airport employes, a few of whom are permitted to hunt there during the winter months to thin out the population.