The Air Accident Investigation Bureau report said there was also some “non-compliance” of emergency regulations.

It concluded that the most probable cause of the crash was the pilot’s inability to use all available information to make the correct decision when flying over water at low altitude in limited visibility, according to a report in The Star.

Among those who died in the crash were deputy plantation industries and commodities minister Noriah Kasnon, Kuala Kangsar MP Wan Mohammad Khairil Anuar Wan Ahmad and plantation industries and commodities ministry secretary-general Dr Sundaran Annamalai.

Others killed in the May 5, 2016, helicopter crash were Noriah’s husband Asmuni Abdullah, her bodyguard Ahmad Sobri Harun and Filipino pilot Captain Rudolf Rex Ragas.

The AS350 helicopter crashed near Batang Lupar, while on the way from Betong to Kuching.

The Star reported that the pilot had made several phone calls before his departure, asking about weather conditions in Kuching.

The pilot was navigating using GPS due to the very bad weather and the fact that he was not familiar with the terrain.

The report said the GPS could have pointed to a direct route to Simunjan but that before he could reach Simunjan at 4.20pm, the weather surrounding Lingga, based on a satellite picture, was covered with squalls and thunderstorms.

The report said it was also believed that the pilot was under “tremendous stress” before the crash.

“Thunderstorm, rain, and lack of local terrain and weather knowledge could have hindered his ability to make effective decisions,” it said.

The Star quoted Transport Minister Liow Tiong Lai as saying that the crash investigators had recommended that foreign helicopter pilots in Malaysia undergo 10 hours of flying under supervision to familiarise themselves with the local terrain and weather patterns.