China Eastern Airlines (MU, Shanghai Hongqiao) has grounded all of its B737-800s following the crash of B-1791 (msn 41474) in Guangxi on Monday, March 21.

The aircraft was operating flight MU5735 from Kunming Changshui to Guangzhou, carrying 123 passengers and nine crew. It crashed mid-flight, descending rapidly from an altitude of 29,000 feet for reasons yet unknown.

Sources told the Sina news agency that the carrier decided to ground its remaining 106 B737-800s immediately, pending further investigation into the causes of the accident. The group has also grounded forty-seven B737-800s operated by subsidiary China United Airlines and a further 70 operated by another subsidiary, Shanghai Airlines.

The Civil Aviation Administration of China (CAAC) has activated emergency procedures to dispatch rescue and investigation teams but has not issued a safety directive mandating the grounding of B737-800s across the country. The ch-aviation fleets module shows that besides the 106 remaining B737-800s operated by China Eastern Airlines, 30 other Chinese carriers operate a total of 1,088 B737-800s.