The helicopter that crashed into a Los Angeles hillside killing NBA legend Kobe Bryant and eight others, was not equipped with vital software that alerts pilots when aircraft are too close to the ground, officials said.
The terrain awareness and warning system, which is designed to send a warning when a collision appears imminent, had not been installed on Bryant's Sikorsky S-76 helicopter, the National Transport Safety Board's Jennifer Homendy said.
"Certainly, TAWS could have helped," NBC News reported Homendy as saying, adding that she could not conclude that its use would have prevented the crash.
The warning system is not mandatory on helicopters under Federal Aviation Administration regulations, despite the NTSB recommending that it be made so on all helicopters with six or more passenger seats, following a 2004 crash.
Also, federal investigators finished their inspection of the crash site, handing it over to local authorities.
Images showed investigators flying drones over the accident site and manually combing through twisted, charred wreckage, which was scattered over a wide area.
Officials also used drones to replicate the helicopter's final, fateful flight path, Homendy said.
Bryant, 41, was travelling with daughter Gianna and seven other passengers and crew when the Sikorsky S-76 slammed into a hillside in thick fog.
The helicopter was headed to Bryant's Mamba Sports Academy in Thousand Oaks, where his daughter was set to play.
Homendy described the accident as a "high energy impact crash".
Investigators have now airlifted the helicopter's wreckage onto trucks, which then transported it to a secure location for further examination.
An iPad, cellphone and maintenance records were found among the wreckage, along with "everything we would expect would be on the aircraft," said Homendy.
She told journalists that the probable cause for the accident may not be confirmed for 12-18 months when a final report will be issued.
A preliminary, fact-based report is expected in 10 days.