Kobe Bryant Helicopter Didn’t Have Critical Warning System, Officials Say

The chopper wasn’t equipped with a terrain awareness and warning system, or TAWS, which could have provided critical information to the pilot about the mountainous area.

Industry officials have estimated the cost of retrofitting such a system—which in some cases can give pilots an audible warning 10 seconds or more before a potential collision with the ground—at roughly $25,000 to $40,000.

The Sikorsky S-76B model rolled out of the factory before the Federal Aviation Administration mandated such equipment on new choppers, but replacement systems have been available for about 15 years. All business jets and airliners have advanced versions of ground-collision warning systems, as do many medical and air tour helicopters.

Los Angeles County Sheriff Alex Villanueva said Tuesday that the coroner’s office had released the names of four of the deceased: Mr. Bryant, Sarah Chester, John Altobelli and pilot Ara Zobayan. Mr. Bryant’s 13-year-old daughter, Gianna, was also believed to be aboard in addition to Keri Altobelli, Alyssa Altobelli, Christina Mauser and Payton Chester.

The NTSB briefed family members Tuesday afternoon but didn’t divulge the details of that discussion.

Federal investigators clarified several details of the plane’s final minutes before the fatal crash. The investigators said they recovered an iPad and cellphone in the wreckage, but they haven’t determined to whom they belonged.

They also said that Mr. Zobayan, the pilot, had 1,250 hours of flight time on the Sikorsky S-76 helicopter, which Jennifer Homendy, an NTSB board member, described as a “good amount of experience.”

Weather Diversion

With low clouds and fog pushing in from the sea, Kobe Bryant’s helicopter followed an unusual route.

Mr. Zobayan made the same trip from John Wayne Airport to Camarillo Airport on Saturday morning but took a more direct flight path in clear weather. In the foggy conditions of Sunday morning, Mr. Zobayan was told to maintain special visual flight rules at or below 2,500 feet, regulations that are “very common,” Ms. Homendy said.

The helicopter lost communications with air-traffic controllers when it climbed to 2,300 feet as Mr. Zobayan attempted to avoid a cloud layer, NTSB officials said. The helicopter then began a descending left turn and crashed into the hills of Calabasas at roughly 1,085 feet above sea level, the officials said. The chopper was descending at more than 2,000 feet a minute.

“Preliminary information is that the helicopter was in one piece when it impacted the terrain,” Ms. Homendy said. “This is a pretty steep descent at high speed.”

Ms. Homendy’s comments suggest the aircraft didn’t experience a dramatic engine malfunction or structural failure that sheared off a rotor or tore through the body of the chopper. Frequently, investigators can definitively rule out such events through metallurgical examinations, which indicate whether blades, shafts or structural pieces ruptured before or after impact.

“It’s important to realize that there’s not one hill,” added Bill English, an investigator-in-charge with the NTSB. “It’s a ravine with undulating terrain, so the small outcropping that had the main impact in it, the main impact was about 20 to 30 feet from the top of that small hill. But there are actually other higher hills surrounding it.”

The NTSB said it would issue a preliminary report in 10 days with factual information. In about 12 to 18 months, the agency said it hopes to issue a final report with findings, a probable cause and safety recommendations.

“The goal is to prevent a similar accident from happening again,” Ms. Homendy said.

The safety board also has been pushing to retrofit older helicopter fleets with new fuel systems that are less prone to burst into flames in the event of a crash.

The NTSB issued a recommendation in 2006 to the Federal Aviation Administration that would have required TAWS in such a helicopter, but the FAA “failed to act,” said Ms. Homendy. The NTSB closed the recommendation as unacceptable in 2014. An FAA spokesman declined to comment.