NEW YORK -- Each year, more than 1,400 students from a heavily black section of southeastern Queens ask city officials to let them go to high school in the more affluent white neighborhoods a few miles to the north.

These students -- nearly half of whom are turned down -- are trying to avoid attending Andrew Jackson High School, a struggling, all-black school that many believe has become a dumping ground for the borough's most unwanted minority students.

Although there are hundreds of empty classroom seats in such nearby white communities as Bayside, Bellerose and Flushing, the New York City Board of Education has placed a strict admissions quota on blacks, part of a policy of keeping those high schools at least 50 percent white.

The Justice Department's Civil Rights Division, which strongly opposes racial quotas, has begun a preliminary investigation of the city's quotas for high schools, a spokeswoman for Assistant Attorney General William Bradford Reynolds confirmed last week.

These quotas have sparked a fierce argument here over what constitutes the "tipping point," the level at which an influx of minorities will cause whites to flee the system. In a city that has seen many of its white middle-class neighborhoods transformed into poor, predominantly black neighborhoods in the last two decades, it is more than an academic debate.

In the mid-1970s, for example, the school board tried to integrate Andrew Jackson by redrawing attendance lines to include hundreds of white families in neighboring Hollis. Instead, one city education official said, "What they did was take a changing neighborhood and change it faster. It turned into an all-minority neighborhood. People sold their houses and moved out."

That failed attempt at integration led to the 50-50 quotas, now being denounced in some quarters.

"While I know people have said that we've got to hold on to the whites that we have, the Constitution doesn't allow that," said Norman J. Chachkin, an attorney for the NAACP Legal Defense and Education Fund, which assailed the policy in a recent report. "You can't say to a kid that because of your race, you can't go to that school over there that has empty seats."

In a pattern seen in urban areas across the country, whites have fled New York's public schools since the 1960s, leaving behind a deteriorating system in which three out of four seats are filled by blacks and Hispanics. Of the 273,000 students at 96 public high schools here, many of the remaining whites are concentrated in about 20 integrated schools, which also happen to be among the best schools in the city.

City officials argue that it makes no sense to destroy this relative handful of integrated high schools in the name of universal desegregation, which they fear would quickly produce an all-minority system.

"This is not the best situation, but it's better than no one getting an integrated education," one official said.

Yet it is a policy that relegates student populations with the least number of whites and the lowest incomes to minority high schools such as Andrew Jackson in Queens and Erasmus Hall in Brooklyn, which then must cope with a disproportionate share of low test scores, truancy and discipline problems.

If Reynolds takes the city to court, it would not be the first time he has challenged a quota system here. Last May, a federal judge struck down a 65 percent quota for white families at Brooklyn's Starrett City, a sprawling subsidized-housing complex, after Reynolds accused the project of "the worst kind of discrimination."

While New York has so far avoided massive court-ordered school busing, many now believe that the city is moving toward a dual system of education.

In Manhattan, nearly 90 percent of public high school students are black or Hispanic, while more than 80 percent of those enrolled in private schools are white. On Staten Island, however, five of the six public high schools are predominantly white; one is 92 percent white.

From the outside, Andrew Jackson High School and Bayside High School appear strikingly similar. Each is a block-long, three-story beige building with a large football field; each is located in a middle-class Queens neighborhood of detached homes and neat row houses, and each recently celebrated its 50th anniversary.

The difference lies in the student bodies. Bayside is half white; Andrew Jackson, less than seven miles to the south, is all black.

Test scores reflect the fact that more of Jackson's students come from poor or troubled homes. Last year, 36.9 percent of Jackson students were reading at a 9th-grade level or above, compared to 67.3 percent of those at Bayside.

In 1985, Jackson, with 2,995 students, was at 108 percent of capacity. Bayside, with 2,512 students, filled only 86 percent of its seats.

These disparities would be far greater had the school board, under a complicated integration plan, not assigned 900 black students to Bayside, a school in the midst of affluence on Queens' north shore.

But once the influx of minorities reduced Bayside's white population to 50 percent -- it dipped below that last year -- no more blacks could be admitted. Instead, as Bayside and other integrated Queens schools hit their limit, more black students must be relegated to Jackson.

"New York City is famous for this -- you keep your upgraded schools wherever whites are attending," said Rose Gibson, whose three sons have attended Jackson. "The truth is that the Board of Education did not care about Jackson. They sent us the students that no one else wanted."

"They mean to keep Andrew Jackson as a school where they can dump the undesirables," said Barbara Clark, the mother of four Jackson graduates. "They have to have a place to put black children and disruptive children. Then you only have one school in the borough that's screaming. It's a good management decision."

Clark, a Democratic state assemblywoman, said these policies have caused a "brain drain" at Jackson. "Most of the people I know sent their kids elsewhere," she said.

It was not always this way. In the 1950s, Jackson was predominantly white. By 1967, when Gibson's oldest son started there, it had become an integrated school where "blacks were still fighting to get their children in," she said.

But the area around Jackson, which stretches south to John F. Kennedy International Airport and north along the Nassau County line, was rapidly changing. The school board kept assigning new white students by enlarging Jackson's attendance area until it was twice as large as any other zone. But white families sent their children elsewhere or moved away, and by 1976, Jackson was 99 percent black.

The board then abandoned efforts to integrate Jackson and adopted the "Controlled Rate of Change" plan, giving students in Jackson's zone the right to seek reassignment to any integrated school in Queens -- as long as that didn't push the other school past the 50-50 mark.

James Meyerson, an attorney for a group of parents who challenged the plan in a 1976 lawsuit, called this "a racist admissions policy, a way of keeping that school a school for the have-nots."

The litigation has become so tangled that, despite two federal appeals court decisions, there has still been no definitive ruling. But the courts have refused to strike down the plan, citing evidence that the rate of white flight doubled at some schools after the proportion of whites dropped below 50 percent.

The 11-year-old policy, administered by the board's Office of Integration and Zoning, is as Byzantine as the New York politics that spawned it.

In theory, any student can apply for admission to dozens of "magnet" programs, from cosmetology to marketing to real estate, at any city high school. Half of those admitted are selected by the schools according to such factors as grades and attendance. The other half are chosen at random by the zoning office under a computer program that airlines use to fill their seats.

A black student with a C average who lives near Jackson, for example, might apply for special magnet programs in music or art at Bayside High School. He may not be accepted because of his mediocre academic record. If the computer doesn't pick him for the "random" group, he will be sent to Jackson.

Chachkin of the NAACP Legal Defense and Education Fund called the process "a sham. There's a very limited number of schools to which minority kids can transfer. . . . It's a very secret program. From year to year the schools change and nothing is ever published."

There are other complications. Last year the school board required that 84 percent of those chosen for magnet programs have average grades or better, meaning that these programs are skimming off more of the best minority students.

Beginning next year, said Bayside Principal Albert Zachter, his school will select all of its music and art students by competition. "You can't run a music program if a computer selects the students," he said. "You may wind up with 40 oboe players, and you can't have an orchestra."

In any event, Bayside is no longer a "receiving" school for minorities because, as of last year, blacks and Asian Americans exceeded white students in number.

Zachter, whose school features Latin courses and other programs for the college-bound, said he is unsure whether further integration would drive white students from Bayside. "Do you prevent tipping," he asked, "or do you let things take their natural course?"

A look inside the much-maligned building on 116th Avenue confounds the conventional wisdom: Andrew Jackson High School is getting much better than its reputation. And many parents, disillusioned with a decade of litigation, prefer to keep it an all-black school.

A 12-person security force keeps things quiet at Jackson. Assistant principals patrol the halls with walkie-talkies, rounding up latecomers. A special office tracks down truants. Behind each door, groups of students -- whether engaged in woodworking, science lab or the renowned gospel chorus -- appear well-behaved.

The school is in impeccable shape, from the freshly painted walls and carefully swept floors to the well-stocked library and modern computer rooms.

Yet the faculty, which, ironically, is half white and half black under a separate integration effort aimed at teachers, is acutely aware of the school's image.

"A lot of parents were reluctant to send their children here," said Principal Leslie Weng, a 1961 Jackson graduate. "They say why take a chance on a school if it's all black?"

But Weng says things are changing, citing special new programs in law and engineering and an increase in college admissions and scholarships. "Many, many places like our kids," she said. "Our reputation is unjustifiably negative."

To be sure, Jackson continues to struggle with a hard core of youngsters who cut classes, get into fights or deal drugs. But many blame this on an admissions policy that forces Jackson to provide remedial reading and math to at least half of its ninth-graders.

Evelyn Rich, principal in 1980-85, said education was often "impossible" because of "over-the-counter admissions," which she defined as assignment of minority students from other areas, sometimes suspended from other schools, to Jackson after the school year had begun.

"It meant you had no classes for youngsters," Rich said. "Some guidance counselors were teaching part time. We had a 10-period day, from 8 a.m. to 3:30, with six lunch periods. We started serving lunch at 10:25."

But late admissions have been curtailed, and overcrowding has been reduced. Still, many staff members believe that too many societal problems are being placed on Jackson's doorstep.

"This is the holding pen to keep minorities out of schools in north Queens," said Assistant Principal Robert Marsh. "People say, 'You have a lot of minorities, it must be a zoo.'

"But kids are learning. Kids are going to college. Our scores are going up. Given the youngsters we've got, we're making gains."

One thing Jackson students do not receive is an integrated education. Marsh says many need speech lessons before they can look for a job.

"What you have here is youngsters from the black community who are not exposed to the main culture, the white middle-class culture," he said. "After they graduate, they go into culture shock -- how do you act, how do you dress, how do you deal with these people?"