HAMMOND - Federal investigators will base much of their investigation into a deadly plane crash around radio transmissions between the airport tower and a doomed aircraft.

The Cessna 421 turbo-prop hit the ground in a near vertical nosedive after making a steep bank, the NTSB said in a news conference Thursday afternoon. The crash happened a day earlier, Wednesday afternoon, as the pilot was attempting to return to the Hammond Northshore Regional Airport after exclaiming "mayday" into the plane's radio.

In a few short seconds, the pilot asks the control tower to allow him to return to the airport. The conversation is brief, and after being told the airplane can return to the airport the pilot screams and the audio cuts out. The audio recordings were played on the 5 p.m. Wednesday edition of WBRZ News 2. The recordings were featured in a lengthy report about the crash on the Wednesday 10pm broadcast on WBRZ channel 2.

Federal investigators said they would not release the identities of the deceased. But, the mayor of Hammond identified the passenger as John Harris. Harris, a business owner, is from Denham Springs.

Investigators did reveal that the pilot made an hour or two stop in Hammond after flying from Jackson to pick up a passenger.

Family members of the pilot identified him on social media as an experienced flier from Lafayette. The plane, tail number N33FA, is registered to a company in Lafayette.

Crash investigators said they will focus on human error, the aircraft and weather as they piece together what brought the plane down Wednesday afternoon between 3:30 and 4:00. The aircraft itself was almost completely consumed by fire, an investigator said. There were no black boxes on an aircraft of this size.

Investigators hope to use security video from around the airport that captured the incident. Investigators will also talk to maintenance workers who did work on the plane. The thorough investigation will take about six months to a year to complete, the NTSB said.

Officials described the flight as business and, as first reported on WBRZ.com Wednesday, the plane was headed to Atlanta. It had arrived in Hammond from Jackson, Mississippi.

While the NTSB would not confirm the pilot's name, an investigator said he had a commercial license to fly planes.

"[This is] obviously a very sad time for the families. We would ask people to recognize that this is a time of mourning," the mayor of Hammond said. 

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