The NTSB revealed that a bell rang in the cockpit when the..

A member of the National Transportation Safety Board (NTSB) said Friday that a UPS cargo plane caught fire, lost an engine, and crashed during takeoff in Louisville, Kentucky, this week. At least 14 people, including the three pilots, were killed in the accident.

NTSB member Todd Inman said the cockpit voice recorder recorded a continuous chime that began approximately 37 seconds after the crew initiated takeoff. The chime continued to ring until the recording ended. Investigators believe this was the point where the plane collided.

Inman said that different types of alarms could have different meanings, but investigators know the plane's left wing was on fire and will use flight data to form a clearer picture of what happened.

The NTSB is leading the investigation. Inman said it will take months for a copy of the cockpit recording to be released to the public as part of the investigation process.

Jeff Guzzetti, a former federal crash investigator, told The Associated Press the bell likely was signaling the engine fire.

"It occurred at a point in the takeoff where they were likely past their decision speed to abort the takeoff," Guzzetti told The AP after Inman's news conference Friday. "They were likely past their critical decision speed to remain on the runway and stop safely. ... They'll need to thoroughly investigate the options the crew may or may not have had."

The accident occurred on Tuesday at UPS Worldport, the company's global aviation hub in Louisville. Dramatic video shows the plane colliding with businesses and bursting into flames. Footage from phones, cars, and security cameras provided investigators with visual evidence of the incident from multiple angles.

Louisville Mayor Craig Greenberg announced on social media Friday evening that another body had been found at the crash site, bringing the "total number of known fatalities" to at least 14.

UPS on Thursday identified the three pilots on board the plane as Captain Richard Wartenberg, First Officer Lee Truitt, and International Relief Officer Captain Dana Diamond.

Bob Travis, president of the Independent Pilots Association, which represents the crew on the UPS flight, told CBS News on Friday that he knew two of the pilots personally. "These were highly trained professionals... You don't fly a wide-body aircraft around the world for UPS unless you have a lot of experience," Travis said.

Travis said his organization is working with NTSB investigators, but he has no doubt the crew would have done everything possible to prevent this outcome. "Our training is robust," Travis said. "Time and again, you encounter situations in flying aircraft where you're missing one engine, or in some cases, two engines. As we saw in the video, I found it momentary and devastating."

Travis said he "believes" the pilots couldn't have done much given the circumstances.

"That's my belief," Travis said. "It seemed like a very difficult situation to overcome."

CBS News has learned that Lewis Fedon and his three-year-old granddaughter, Kimberly Asa, were among those killed in the crash.

Matt Sweets, a father of two, was pulled from the wreckage but later died in the hospital, CBS News has learned.

Angie Anderso, 45, is among the nine people still missing, CBS News has also learned. Her friends believe she was at a scrap metal recycling center when the plane crashed.

Travis said the union will stand with the survivors and the families of the victims.

"They were in the wrong place at the wrong time...and our hearts go out to them, just like our hearts go out to the pilots," Travis told