The news cast a pall over the Hethel factory, shocking Lotus's 1,100 workers and producing a flood of tributes to Mr Yahaya, who was a close friend of the Malaysian Prime Minister Dr Mahathir Mohamad, and one of the country's most powerful businessmen.
Mr Yahaya, 50, was chairman of the giant Malaysian holding company Hicom, which owns the car maker Proton and several other industrial, export, finance and banking companies.
He invested pounds 10m of his personal fortune in the takeover of Lotus last October, taking a 16 per cent stake in the company. Proton took a further 64 per cent giving the Malaysians a controlling 80 per cent stake.
News of his death emerged on the same day as Lotus announced further investment at the Hethel plant on new engine test facilities. Under its new ownership, production is being expanded to 2,500 cars a year with output of the Elise model due to increase from 750 last year to 1,900 in 1997. Production of the Esprit is expected to rise from 300 to 400 cars a year.
A spokesman said that Mr Yahaya's death would not affect its investment plans although he was unable to say what would happen to his shareholding.
Romano Artioli, the Italian entrepreneur and former Lotus chairman who brokered last autumn's deal and still retains a 20 per cent minority stake, said: "Tan Sri was a great friend of Lotus who believed in the company traditions and appreciated the exceptional ability of its engineers. He had a great vision for the future of the company and we will ensure that we succeed in carrying through this vision."
Mr Yahaya and his wife were killed flying to the eastern state of Pahang. The pilot of the helicopter was also killed. The cause of the crash is under investigation.
An automotive engineer who gained a degree from Loughborough University, Mr Yahaya was one of a handful of well- connected ethnic Malay, or "Bumiputera" entrepreneurs groomed to boost efficiency and bolster exports from Malaysia's lumbering state enterprises. In 1995, he took the reins of Malaysia's "national" car maker, Proton.