China's aviation regulator said on Monday it had ordered Chinese airlines to suspend their Boeing Co 737 MAX aircraft operations by 6pm following a deadly crash of one of the planes in Ethiopia.

An Ethiopian Airlines 737 MAX 8 bound for Nairobi crashed minutes after take-off on Sunday, killing all 157 people on board.

It was the second crash of the 737 MAX, the latest version of Boeing's workhorse narrowbody jet that first entered service in 2017.

In October, a 737 MAX 8 operated by Indonesian budget carrier Lion Air crashed 13 minutes after take-off from Jakarta on a domestic flight, killing all 189 passengers and crew on board.

The Civil Aviation Administration of China (CAAC) said in a statement it would notify airlines as to when they could resume flying the jets after contacting Boeing and the US Federal Aviation Administration (FAA) to ensure flight safety.

"Given that two accidents both involved newly delivered Boeing 737-8 planes and happened during take-off phase, they have some degree of similarity," the CAAC said, adding that the order was in line with its principle of zero-tolerance on safety harzards.

The 737 MAX 8 is sometimes referred to as the 737-8.

The cause of the Indonesian crash is still being investigated. A preliminary report issued in November, before the cockpit voice recorder was recovered, focused on airline maintenance and training and the response of a Boeing anti-stall system to a recently replaced sensor but did not give a reason for the crash.

Chinese airlines have 96 737 MAX 8 jets in service, the state company regulator said on Weibo, including Air China, China Eastern Airlines, China Southern Airlines and Hainan Airlines.

Chinese aviation data firm Variflight said at least 29 international and domestic flights on Monday had been canceled and that airlines had swapped out the plane on 256 other flights that had been scheduled to use it.

China Eastern’s chairperson, Liu Shaoyong, told financial publication Caixin on the sidelines of a parliament meeting in Beijing that it would only consider resuming 737 MAX 8 flights once Boeing issued a safety commitment for the jets and proved that there was no aircraft design link between the two crashes.

Caijing, a Chinese state-run news outlet that covers finance and economics, said many flights scheduled to use 737 MAX planes would instead use the 737-800 models.

Boeing said on Monday the investigation into the Ethiopian Airlines crash is in its early stages, and there is no need to issue new guidance to operators of its 737 MAX 8 aircraft based on the information it has so far.

“Safety is our number one priority and we are taking every measure to fully understand all aspects of this accident, working closely with the investigating team and all regulatory authorities involved,” a Boeing spokesperson said in a statement emailed to Reuters.

A US official told Reuters the United States was unsure of what information China was acting on.

The US official, speaking on condition of anonymity due to the sensitivity of the matter, said there were no plans to follow suit given the 737 MAX had a stellar safety record in the United States and there was a lack of information about the cause of the Ethiopian crash.

Western industry sources say China has been at pains in recent years to assert its independence as a safety regulator as it negotiates mutual safety standard recognition with regulators in the United States and Europe.

In 2017, it signed a mutual recognition deal with the FAA, but industry sources say it has struggled to gain approval from the FAA that would allow it to sell its C919 airliner to Western airlines.

Safety standards

According to flight tracking website FlightRadar24 there were no Boeing 737 MAX 8 planes flying over China as of 8.40am on Monday.

Most of Air China Ltd's 737 MAX fleet of 15 jets landed on Sunday evening, with the exception of two that landed on Monday morning from international destinations, according to data on FlightRadar24.

It did not list any upcoming scheduled flights for the planes, nor did China Southern Airlines Co, which also has its fleet on the ground.

China Eastern Airlines Corp Ltd four 737 MAX jets landed on Sunday evening and no further flights were scheduled until Tuesday, FlightRadar24 data showed.

Ethiopian Airlines said it had grounded its 737 MAX 8 fleet until further notice as an “extra safety precaution” even though it did not know the cause of Sunday’s crash.

The airline has a remaining fleet of four of the aircraft, according to FlightRadar24.

Cayman Airways has grounded both of its new 737 MAX 8 jets until more information was received, the Cayman Islands airline said in a statement on its website.

Fiji Airways said it had followed a comprehensive induction process for its new Boeing 737 MAX 8 aircraft and it had full confidence in the airworthiness of its fleet.

"We continue to ensure that our maintenance and training programme for pilots and engineers meets the highest safety standards," the airline said.

Singapore Airlines Ltd, whose regional arm SilkAir operates the 737 MAX, said it was monitoring the situation closely, but its planes continued to operate as scheduled.

Indonesia said it would continue to monitor its airlines operating the 737 MAX, which include Lion Air and Garuda Indonesia but it did not mention any plan to ground the planes.

- Reuters