Pilot Was Talking to Air Traffic Control, Reading Directions When Helicopter Crashed into Radio Tower: NTSB

• A helicopter that went on a sightseeing tour crashed into a Houston radio tower on Oct. 20, killing the pilot and three passengers
• The NTSB said in a preliminary report that the transmission between the helicopter pilot and air traffic abruptly stopped moments before the deadly crash
• The tower’s top and middle beacons were flashing as the chopper headed toward the tower, according to the report

The pilot of a helicopter that crashed into a Houston radio tower on Oct. 20, killing all four people aboard, was in contact with air traffic control moments before the tragedy occurred, officials said. 

According to a preliminary National Transportation Safety Board (NTSB) report obtained by PEOPLE and issued almost two weeks after the incident, the pilot of the Robinson R44 helicopter, later identified as Samantha Grandbouche, was speaking to the air traffic controller and requested “the downtown loop.”

Then, several minutes later, the air traffic controller issued a traffic advisory for the company tour helicopter, the report stated, with Grandbouche acknowledging that there was traffic in sight through her Automatic Dependent Surveillance Broadcast.

“The controller requested the accident pilot to maintain visual separation from the traffic, and the pilot was reading the instructions when the radio transmission abruptly ended. No further communications from the accident helicopter were received.”

The helicopter, which departed from Ellington Airport in Houston for a sightseeing tour, crashed into the tower about 100 feet from the top of the 1,003-foot radio tower, added the report. According to surveillance footage, the tower’s top and middle beacons were flashing as the chopper headed toward the tower. 

“During the impact with the radio tower, there was an explosion, and the helicopter fell to the ground,” the NTSB preliminary findings stated. “The radio tower collapsed onto the helicopter, and a post-impact fire destroyed the helicopter.”

In addition to Grandbouche, the three passengers killed in the crash were family members Julio Cesar Lerma, Marie Alonso and Dylon Lerma, according to the Harris County Institute of Forensic Sciences, the CBS affiliate KHOU reported.

PEOPLE has reached out to the Harris County Institute of Forensic Sciences for comment.

The NTSB report also stated that the debris field contained sections of “plexiglass, main rotor blades, console components, upholstery, flight controls, and landing gear.” Parts of the forward fuselage were stuck in the tower “about 100 ft from the top.”

The report's findings did not indicate what caused the crash. A final report is expected to be issued in 18 to 24 months, the Associated Press reported. 

Garrett Kauffman, a friend of Julio Cesar Lerma, one of the four people killed aboard the helicopter, remembered Lerma, who worked in home remodeling. 

“He always came to the rescue,” Kauffman told KHOU. “He just said, ‘OK, yeah, we can do that, we can figure this out. He was a true friend.”

Lerma was a father to three sons, said Kauffman, Relatives said Dylon Lerma, who also died in the crash, was Lerma’s youngest son, KHOU reported. 

“I think he lived life to the fullest,” Kauffman added of his friend. “I think he would do, like I said, anything for those boys. A total professional, always, and he’ll be missed. I miss him every day."

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Ronnie Zepeda, a longtime neighbor of Lerman, told ABC affiliate KTRK that he saw Lerman just hours before the incident. 

"Him and his little boy, they were here,” Zepeda said. “The little boy was running around."

Zepeda later fondly said of Lerman: "He was a very fine gentleman. He was a very good human being. Exceptional neighbor. We loved him. We loved him very much."

A GoFundMe was launched to raise money for Lerma’s surviving eldest sons. 

Meanwhile, Houston-based law firm Sorrels Law announced it is representing the Lerma's family members and the other two passengers killed in the crash and filing a lawsuit on their behalf against Grandbouche, the owner of the radio tower and the helicopter company, NBC affiliate KPRC reported. 

“Our clients deserve answers, and we are determined to uncover the truth about what led to this tragedy,” said attorney Randy Sorrels in a Facebook post on Friday, Nov. 1. “By seeking accountability, we hope to prevent future accidents and bring some peace to families who have endured so much loss.”

PEOPLE contacted National Helicopter Solutions, the helicopter company, and SBA Communications, the owner of the radio tower, who were named in the lawsuit on Nov. 1.