The helicopter that crashed, killing basketball great Kobe Bryant, his daughter and seven others, was not certified to fly in foggy conditions.
According to officials, Island Express Helicopters, which owned the Sikorsky S-76B that crashed, was allowed to operate under visual flight rules.
"The preliminary information is Island Express' 135 certificate did not allow for IFR flight," said Keith Holloway, a National Transportation Safety Board spokesman. "No other specifics are available at this time."
Preliminary investigations have pegged foggy weather conditions as a possible cause for the crash.
Meanwhile, the Lakers played their first game since Bryant's death, and paid tribute to the star by wearing his numbers - 8 and 24 - during warm-up. They went against the Portland Trail Blazers at the Staples Center in LA.
President Donald Trump said on Sunday the US Navy would immediately start blockading the Strait of Hormuz, raising the stakes after marathon talks with Iran failed to reach a deal to end the war, jeopardising a fragile two-week ceasefire.
At least 200 people are feared dead after Nigerian military jets struck a village market while pursuing rebels in the northeast of the country on Saturday night, a councillor for the area and residents said on Sunday.
Russia and Ukraine accused each other on Sunday of breaching the 32-hour ceasefire in their four-year war, reporting more than a thousand drone and shelling attacks just hours after the truce began on Saturday to mark Orthodox Easter.
At least 30 people were killed on Saturday in a stampede at the Laferriere Citadel in the northern countryside of Haiti, authorities said, warning that the death toll could rise.
A cyclone battered New Zealand's North Island on Sunday, cutting power to thousands of residents and forcing hundreds to evacuate, as officials warned conditions would worsen through the day.