The death of Osama bin Laden's three family members, said to include the slain Al Qaeda chief's stepmother and half-sister, remains shrouded in mystery as questions are being raised over the cause of the plane crash in UK despite normal weather and runway conditions.   

The Phenom 300 jet arriving from Italy that crashed while attempting to land at Blackbushe Airport in Hampshire, some 65 kilometres from London, is equipped with fly-by-wire electronic system that is supposed to make it easy to control.   

The 7 million pound Embraer jet was also a regular visitor to the airport, The Guardian reported, citing pilots who use Blackbushe.   

The Saudi Arabia-registered plane had ploughed into a carauction site and burst into flames, killing all four persons on board and believed to have been carrying Osama's stepmother Rajaa Hashim and sister Sana from the bin Laden family, a prominent Saudi clan with vast business interests.

Photograph: Reuters video grab   

Media reports said Sana's husband Zuhair Hashim and a Jordanian pilot were also among the dead. The family were"visiting the UK on vacation", according to police.