A Delta Air Lines pilot didn’t inform air traffic control it planned to dump fuel during an emergency landing back at Los Angeles Airport. Instead, he answered ‘Negative’ when asked if he needed to do so and then dumped fuel over south LA where it fell on several school playgrounds causing minor injuries to dozens of children and adults on the ground.

Delta said it sent a cleaning crew ‘to clean all outside surfaces that students could come into contact with’ after people were treated for skin irritation and breathing difficulties.

In an audio recording made public between the pilot and an air traffic controller, the pilot said the flight would return to Los Angeles International Airport because one engine had compressor stalls.

Pilot: “We’ve got it back under control. We’re going to come back to LAX. We’re not critical. We’re going to slow to 280 knots, and uh, why don’t you point us downwind at 8,000 feet (unintelligible) and we’ll turn back to LA.”

Tower: “OK, so you don’t need to hold or dump fuel or anything like that?”

Pilot: “Uh, negative.”

That has raised questions about the pilot’s subsequent actions, because the pilot broke from normal protocol.

Pilots typically notify air traffic control of the need to offload fuel to reduce weight to enable a safer landing.

A controller would then instruct a pilot to an appropriate area and altitude.

“A review of yesterday’s air traffic control communications shows the Delta Flight 89 crew did not tell air traffic control that they needed to dump fuel,” the Federal Aviation Administration said.

The FAA said the fuel dumping procedure did not occur at the optimal altitude that would have allowed the fuel to atomize properly.

The pilots’ actions have left aviation experts puzzled.

“I know that there are a lot of questions about the process that was followed.” said Dana Debel, Delta’s managing director of government affairs.

The FAA investigation is still ongoing.