The cockpit voice recorder of the UPS cargo jet that crashed in Louisville on Tuesday revealed the sound of a bell heard in the cockpit.

Dozens of federal aviation investigators are on the ground in Louisville searching the crash site's debris field, which covers nearly a half-mile area.

Investigators probing the Nov. 4 crash of a UPS McDonnell-Douglas MD-11 freighter are analyzing data from both of the aircraft’s onboard recorders and expect to have more insight into what caused the fatal disaster in the coming days. The aircraft’s flight data recorder (FDR) and cockpit voice...

The flight data (FDR) and cockpit voice (CVR) recorders have been flown to the NTSB lab in Washington D.C., where the information they contain will be analyzed. The FDR has 63 hours of information covering the last 24 flights made by the aircraft. The CVR contains two hours of audio, including the accident flight.

UPS Flight 2976 crashed around 5:15 p.m. local time on Tuesday, officials said. The McDonnell Douglas MD-11 freighter plane was headed to Daniel K. Inouye International Airport in Honolulu, when the plane's left engine detached after a "large plume of fire" erupted from the plane's left wing, according to the NTSB.