LOS ANGELES (AP) _ Two airliners coming in for landings with 168 people aboard came within 10 to 30 feet of colliding over a residential neighborhood when one failed to make a slight turn ordered by controllers, officials said.

The near collision involving a Mexicana airliner and a Westair jet occurred Thursday night about 2,000 feet over the South Los Angeles-Inglewood area, said a Federal Aviation Administration duty officer who declined to give his name.

The incident was one of four that occurred at Los Angeles International Airport on Thursday, National Transportation Safety Board spokesman Alan Pollack said Friday, adding that all four would be investigated.

The other incidents involved a near collision between a taxiing airliner and one taking off, an accident in which a taxiing plane hit one that was parked, and a Sheriff's Department helicopter that came too close to a plane while flying through a restricted area, officials said.

No injuries were reported in any of the incidents.

The Mexicana plane, carrying 138 passengers and a crew of 15, was arriving from Mexico City around 9:15 p.m. Thursday as the Westair jet, with 13 passengers and two crew members from San Diego, was heading for a parallel runway.

Mexicana Airlines spokeswoman Ruth Shari said the two aircraft passed within 30 feet of each other, but Pollack put the distance at 10 feet. Officials would not say what kind of aircraft were involved.

FAA officials said the Mexicana airliner failed to make the small turn ordered by controllers.

''Westair was anticipating, apparently, that the Mexicana would move over and it didn't happen,'' said FAA controller Karl Grundman, who was in the airport tower at the time.

Three hours before that, Delta Airlines Flight 1445, carrying 38 passengers and a crew of six to Anchorage, Alaska, via Portland, Ore., nearly collided on the ground with Westair Flight 3246, which had just landed with 13 passengers and a crew of two from Fresno.

The Delta flight was beginning its final takeoff roll as the Westair plane was taxiing across the runway to a terminal gate, officials said. The Westair crew reportedly saw the Delta plane coming and got out of its way.

Two hours later, a Pacific Southwest Airlines jetliner was being taxied by mechanics when it hit an Eastern Airlines L-1011 that was parked away from a runway. No passengers were on either plane, and no one was hurt.

Neither airline had completed damage estimates Friday, but it was believed repairs could cost millions of dollars.

In the fourth incident, a Los Angeles County Sheriff's Department helicopter was crossing the airport's Terminal Control Area when it failed to maintain the required horizontal distance from another aircraft, officials said.

NTSB officials would not say who appeared to be at fault and it was not immediately known how close the helicopter had come to the other plane, the size of the plane or how many people were on it.

On Tuesday, a United Airlines jetliner with 289 people aboard and traveling at 175 mph as it approached takeoff narrowly missed colliding with a Delta Airlines plane on the ground at Los Angeles International.