China's Civil Aviation Administration has issued an "Emergency Airworthiness Directive" to impose compulsory safety checks on Boeing 737s. The directive follows a similar check issued by the US Federal Aviation Administration on March the 12th.

The FAA ordered Boeing planes to be checked for potential safety hazards caused by the tail rudder. The company identified the problem after a flight crew noticed excessive vibration and was forced to divert but finally made a safe landing. The tail rudder controls the amount of lift the plane gets, changing the angle of the rudder can make the plane rise or fall.