New York CNN  — 

Investigators are probing the narrowly avoided catastrophic collision between two airliners at New York’s JFK airport Friday evening and are already conducting interviews, according to the National Transportation Safety Board.

The incident involved an American Airlines 777 that improperly crossed an active runway at the busy airport. “S**t!” an air traffic controller called out over the radio, urgently directing a Delta Air Lines 737 to stop its takeoff from the same runway where the American plane rolled across its direct path. The Delta plane stopped within 1,000 feet of the American jet.

NTSB spokeswoman Sarah Sulick told CNN interviews related to the investigation are ongoing, a detail that has not yet been reported elsewhere. She provided no further details.

American (AAL) spokesman Derek Walls said the airline is “conducting a full internal review and cooperating with the National Transportation Safety Board in their investigation.” The union representing American (AAL) pilots, the Allied Pilots Association, said, “We respect the process and we’re going to let that run its full course.”

Another source of information investigators typically turn to when determining what happened inside the cockpit of an airliner incident is the cockpit voice recorder, one of the two so-called black boxes. Investigators will be able to listen to the radio transmissions, which have already been recorded and preserved. The conversations between crew members that are not broadcast over the radio are picked up by the CVR.

“You want to listen to the conversations and the procedures that were being followed in the cockpit prior to the incident,” said Peter Goelz, a former NTSB managing director and a CNN aviation analyst. Those recordings would also reveal if the American pilots heard the instructions completely from the air traffic controllers and if so, how they apparently became confused.

But that audio may not be available in at least one cockpit, Goelz warned. Because the American Airlines flight continued on to London that evening, it is unclear if investigators had access to the recordings before they were overwritten.

“The challenge is voice recorders only record two hours of activity in a cockpit,” Goelz said. “So by the time they landed in London, this recording could have canceled out and there will be no coverage of what happened within the cockpit.”

Neither the NTSB nor any of the parties CNN has contacted have commented on the voice recorder.

Push to improve technology

The NTSB has made several recommendations to improve voice recorders, including that the recording length be extended to 25 hours, something that would have preserved the cockpit chatter from the American crew even if it wasn’t retrieved until the flight landed in London. In a 2018 report, the board said “recent safety investigations have been hampered because relevant portions of the recordings were overwritten.”

The report identified 14 investigations since 2003 where data on a two-hour voice recorder was overwritten. “Lacking these data means that an investigation may not identify issues that played a role in the event, which could result in a similar —or worse — occurrence in the future,” the report continued.

The FAA has not acted upon that recommendation and did not immediately respond to CNN’s request for comment.

If the voice records inside the American cockpit are preserved, they may depict a detailed conversation about the aircraft’s on-the-ground movements. At many airlines, both pilots are involved in confirming and carrying out controller’s instructions to navigate taxiways and runways, according to a pilot who requested anonymity because of strict rules about speaking to reporters.

Each airline has its own procedures, the pilot said, but those typically include the pilot helming the radio reading back instructions given by air traffic controllers, and the pilot steering the plane subsequently repeating those instructions. Both opportunities offer an opportunity to notice a discrepancy.

The pilots would then work together, the pilot said, verbally calling out runway and taxiway markers, and each checking his or her side of the aircraft for any oncoming traffic. Airline procedure may even call for pilots to turn on additional airplane lighting when crossing runways, in part to make the plane more visible to others.

Investigations into incidents like this frequently begin when the control tower notices an error and gives the pilots a phone number to call, the pilot said.

In this incident, radio recordings show controllers instructed the American pilots to place a phone call to officials at the tower to address the “possible pilot deviation” from the assigned route.