The UAE's aviation regulator said it was taking the precautionary measure of grounding the Boeing aircraft model involved in the Ethiopian Airlines crash on Sunday that killed 157 people. Flydubai, the only UAE operator to use the 737 Max, said on Wednesday that it had grounded the aircraft after the General Civil Aviation Authority's order. Flights to Baghdad, Kabul and Beirut were cancelled on Wednesday, according to the Dubai International Departures board. The airline said it was adjusting its schedule to minimise disruption to passengers and would operate flights with its fleet of next-generation 737-800 aircraft. Flydubai operates 11 of the 737 Max 8, two Max 9 and has 237 more on order. From one minute past midnight on Wednesday, 737 Max 8 was banned from flying in UAE airspace as a precautionary measure, the GCAA said. The 737 Max 9 has also been grounded. The decision has been "issued to ensure the safety of the UAE civil aviation industry and the public of the UAE", the authority said. The GCAA instructed any airline with planes en route to request special approval to fly out of the UAE. Investigators from the authority are working with the US Federal Aviation Authority and Boeing to gather more information. Also on Tuesday, the European Union's aviation safety agency suspended European airspace to the two Boeing models "as a precautionary measure". The UK, South Korea, Australia and Singapore also joined China and others in suspending flights for the Boeing models, most of which are less than a year old. On Wednesday, Lebanon also followed and closed its airspace to the aircraft. The US and Canada are still allowing the aircraft to operate until more information is available from the FAA. After two 737 Max 8 jets crashed within six months, 33 countries and nearly 30 airlines have cancelled operations of the fuel-efficient aircraft in the span of two days. Late on Monday, investigators from the US agency and America's National Transport Safety Board said they were at the site 62 kilometres south-east of Addis Ababa, where the 737 Max 8 took off on Sunday, then crashed six minutes later. Witnesses described the plane veering from side to side, billows of smoke marking its path, before hitting the ground. "The plane rotated two times in the air and it had some smoke coming from the back, then it hit the ground and exploded," Tamrat Abera told Associated Press. Two black boxes, one containing cockpit voice recordings and another containing digital data, were recovered from the crash site on Monday. The boxes could reveal the answers to questions about the Boeing model. An airline official said one of the recorders was partly damaged but "we will see what we can retrieve from it". The single-aisle 737 Max 8 is the company's fastest selling model, used by 59 operators worldwide, but has been in two accidents in five months. The jet was also in use during a Lion Air crash in October, which killed all 189 on-board. Boeing said it would <a href="https://www.thenational.ae/business/aviation/boeing-to-upgrade-software-on-737-max-narrow-body-fleet-within-weeks-1.836002">introduce a software update</a> it had been developing since the first incident. The US authority said on Monday that it would continue to certify the 737 Max 8's airworthiness. If it identified a safety problem, it would take immediate and appropriate action, the regulator said. The American authority said Boeing would issue "enhancements" to the MCAS system, an anti-stalling feature found to cause confusion in the Lion Air crash, by April. It will also update training requirements and flight crew manuals of the aircraft. The FAA is the licensing authority for all American-made aircraft and has the power to ground all 737 Max 8 planes. At the moment, the details linking the Lion Air crash and Ethiopian crash are only circumstantial. Experts say the results of the investigation should be released before conclusions are made. "Comparing this accident with Lion Air is difficult because as a result of the Lion Air accident, all of the pilots should have been briefed on this system and how it behaves and how to deal with it in emergencies," Max Kingsley-Jones, executive director at aviation consultancy FlightGlobal, told <em>The National</em>. Among the victims of the crash were aid workers, doctors and academics. The UN said it had lost 21 members of staff, while four workers from Catholic Relief died and one from Care. Other victims included a Canadian professor, a French Tunisian youth leader and a Kenyan hotelier. Many on board were heading to the UN Environment Assembly, which began on Monday with a minute's silence and commemorative speeches, while flags flew at half-staff.