An 8-year-old girl who was orphaned in 1977 when her parents were killed in a spectacular plane crash in Reston will receive $750,000 under a settlement reached yesterday in U.S. District Court in Alexandria.

The agreement, reached after hours of late night haggling among lawyers Monday, brought an abrupt end to the jury trial over the accident.

Grandparents of the girl, Jennie Ottinger, had sued the plane's owner and the estate of the pilot, who was killed in the crash, for $5.5 million, for the "wrongful deaths" of their children, Harry Ottinger III, 31, and his wife, Sue Ellen, 29.

The Ottingers were killed on Nov. 30, 1977, when a twin-engine Piper Aztee piloted by Joseph L. Reid plowed into their Reston townhouse while the couple was home for lunch.

Jennie Ottinger was in school at the time of the accident. The suit originally was brought on her behalf by her grandparents, Harry and Susan Ottinger of New Mexico, and Ralph E. and Margie J. Anderson of Massachusetts.

Before the case was settled, Jennie's maternal grandmother, Margie Anderson, had testified that the girl's "first six years of . . . life were completely wiped out" by the crash. She said however, that the young girl appeared to have adjusted to the loss of her parents.

Other allegations that were expected to be presented included charges that the weather and visibility at the time the pilot set out from Ohio State University were so poor that the flight never should have been made.

The pilot, who was delivering the plane owned by Harry L. Riggs of Kentucky to a new owner in the Washington area, had made two attempts to land at fog-shrouded Dulles International Airport near Reston just before the crash, according to accounts at the time.

Terms of the settlement were not disclosed in open court. One of the Ottinger attorneys, Richard Ben-Veniste, said that the young girl's family agreed to the settlement because it was fair. "We felt that the offer was good," he said. "It was a very respectable settlement."