Sheikh Ahmed is a member of Abu Dhabi's ruling family
A search is on in Morocco for a leading member of the Abu Dhabi ruling family after a glider he was in crashed into an artificial lake south of Rabat.
Sheikh Ahmed bin Zayed al-Nahayan, a younger brother of Abu Dhabi's ruler, manages what is thought to be the world's biggest sovereign wealth fund.
The glider pilot was rescued and is in good condition, state media say.
Sheikh Ahmed was No 27 on Forbes's list of the world's most powerful people last year and is in his early 40s.
Abu Dhabi Investment Authority (ADIA), of which the sheikh is managing director, is believed to have assets of around $500-$700bn, including a stake in Britain's Gatwick airport and residential property in major cities, Reuters news agency reports.
While he is a brother of Sheikh Khalifa bin Zayed, who as well as ruling Abu Dhabi heads the UAE, Sheikh Ahmed is not immediately in line for the succession.