The pilot of the helicopter that crashed in thick fog, killing Kobe Bryant and seven other passengers, reported the aircraft was ascending when it actually was heading for the ground, federal investigators said in documents released Wednesday. Ara Zobayan radioed to air traffic controllers that he was climbing to 4,000ft (1,220m) to get above clouds on January 26 when, in fact, the helicopter was plunging toward a hillside where it crashed northwest of Los Angeles, killing all nine people aboard. The report by the National Transportation Safety Board (NTSB) said Zobayan may have "misperceived" the angles at which he was descending and banking, which can happen when a pilot becomes disoriented in low visibility. Aviation experts said shortly after the crash that the path of the flight indicated Zobayan had lost his bearing. "Calculated apparent angles at this time show that the pilot could have misperceived both pitch and roll angles," one report stated. "During the final descent the pilot, responding to (air traffic control), stated that they were 'climbing to four thousand.' The 1,700 pages of reports do not offer a conclusion of what caused the crash but compile factual reports. A final report on the cause is due later. Bryant, his 13-year-old daughter, Gianna, and six of their friends were killed, along with Zobayan. About 45 minutes before takeoff, Zobayan had texted a group of people overseeing the flight that the weather was looking "OK." He took off from John Wayne Airport in Orange County at 9:06 a.m. with the eight passengers he had flown the day before to the same destination: a girls basketball tournament at the retired Lakers star's Mamba Sports Academy in Thousand Oaks, a city approximately 40 miles north of Los Angeles. When the helicopter hadn't landed within an hour, an executive of the company that operated the aircraft began a frantic search for it on tracking software and had another company helicopter dispatched to look for it. "The weird thing, though, is that the tracker had stopped at 9:45am which is not normal and we were trying to reach Ara over the radio," noted Whitney Bagge, vice president of Island Express Helicopters. "I kept refreshing the tracker praying that it was just broken." Brady said the original flight time for Sunday was 9:45 am, but Bryant had it rescheduled to 9 am because he wanted to see another team play before his daughter's game.