What is known about the China Eastern plane crash?

WSJ: Black box suggests crash was intentional Data from the black box of the crashed China Eastern Airlines flight suggests the 747 may have been crashed intentionally, say new reports.

BEIJING — The crash of a Boeing 737-800 passenger jet in China's southwest started a fire big enough to be seen from space and forced rescuers to search a rugged, remote mountainside.

One day after the China Eastern Airlines flight plunged from the sky, there are more questions than answers.

WHAT CAUSED THE CRASH?

The cause is unknown. Flight 5735 was at 29,000 feet (8,800 metres) on Monday afternoon when it went into a dive about an hour into its flight, according to flight-tracking website FlightRadar24.com.

The plane plunged to 7,400 feet (2,200 metres) before regaining about 1,200 feet (360 metres), then dived again. It crashed into the side of a mountain in a remote, forested area outside the city of Wuzhou.

State media and Chinese regulators gave no indication the pilot reported trouble or other information that might shed light on the cause of the disaster. The plane stopped transmitting data 96 seconds after it started to fall.

Rescue workers planned to use drones in the search for the plane's black boxes, which should contain information from instruments and sound from the cockpit.

Confirming the cause of a plane crash sometimes takes months or years due to the need to gather badly damaged debris and examine specialized technical factors.

HOW MANY PEOPLE WERE ABOARD? DID ANY SURVIVE?

The plane was carrying 123 passengers and nine crew members from the city of Kunming in China's southwest to Guangzhou, an export hub in the southeast.

No survivors have been found as rescuers search the rugged, charred mountainside in the semitropical Guangxi region.

No foreigners are believed to have been on board. Two Chinese companies said their employees were on the flight, including the CFO of Guangzhou-based Dinglong Culture Co. whose interests range from mining to TV and movie production.

Family members gathered in closed-off waiting areas at the airports in both Guangzhou and Kunming. Chinese news reports said five hotels with 700 rooms had been requisitioned closer to the crash site for family members.

IS THIS THE SAME BOEING MODEL INVOLVED IN EARLIER CRASHES THAT RESULTED IN ITS GROUNDING?

No. The plane that crashed was a Boeing 737-800, not the Boeing 737 Max, a newer model that was temporarily grounded worldwide following two deadly crashes in Indonesia in 2018 and Ethiopia in 2019.

The 737-800 is a twin-engine, single-aisle plane commonly used for short and medium-haul flights. In a typical configuration, it has 178 seats divided between the main and premium cabins. Boeing has delivered more than 5,100 of them over the past 24 years, and China is the biggest market, with nearly 1,200, according to aviation consultant IBA.

The plane has been flying since 1998 and has an excellent safety record, said Hassan Shahidi, president of the Flight Safety Foundation. They have been involved in 22 accidents that damaged the planes beyond repair and killed 612 people.

China Eastern grounded all of its 737-800s after the crash, China's Transport Ministry said.

The Boeing 737 Max, which entered service in 2017, was grounded by regulators following the two crashes. They were blamed on a computer system that pushed the nose downward in flight and couldn't be overridden by pilots.

Airlines were allowed to resume using the 737 Max after Boeing redesigned the system in a process overseen by regulators from the United States, Europe, China and the Middle East.

WHAT WILL THE INVESTIGATION LOOK LIKE?

China will lead the investigation, which will include a representative from the U.S. crash investigator, called the National Transportation Safety Board, plus representatives from Boeing and CFM, the General Electric-Safran joint venture that made the engines on this plane.

Key to the investigation is recovering the so-called black boxes -- they are usually painted orange for visibility, but the longtime name has stuck. One device, called the flight data recorder, captures information about the plane's airspeed, altitude, direction up or down, pilot actions, and performance of all key systems. The cockpit voice record captures sounds including conversations and background engine noise during the flight.

Investigators will look at the maintenance history of the plane, the training and record of the pilots, communication the pilots had with air traffic control and weather data. They will examine pieces of the wreckage for clues. Even the size of the debris field is important -- when wreckage is spread over a very large area, it could indicate that the plane was breaking up before hitting the ground.

DOES THE DESTUCTION OF THE PLANE MAKE IT HARDER TO FIND THE CAUSE?

As long as the black boxes survived and can be downloaded, investigators should be able to get a good idea of what happened.