On December 2, Civil Aviation Administration of China issued the Airworthiness directive on the Correction of Unsafe State of MCAS for Mobile Performance Enhancement System (No. CAD 2021-B737-19, Amendment No. 39-10792). The directive applies to all Boeing 737MAX aircraft with serial numbers.
For the Boeing 737MAX in China, the airworthiness directive means there are no legal hurdles to go around, but it could be months before the 737MAX actually flies again.
The test flight lasted for 4 months and the airworthiness order was finally obtained
In October 2018 and March 2019, two Boeing 737-8 planes operated by Indonesia's Lion Air and Ethiopia Airlines crashed. The investigation results showed that the two accidents were caused by the incorrect activation of the MACS system of Boeing 737-8. At that time, the flight crew could not effectively identify, locate the fault and take appropriate measures under the interference of multiple alarms, resulting in the loss of control of the aircraft.
Boeing grounded its 737MAX fleet worldwide as a result of the accident, and the company has initiated design changes to its flight control system software and display system software.
In March 2019, When talking about the grounding of the aircraft, Li Jian, then deputy director of the Civil Aviation Administration of China, revealed that there have been many cases of inaccurate data of the Boeing 737MAX's Angle of attack (AOA) detector in China. If pilots encounter inaccurate AOA data during manual control, it will bring operational difficulties.
"At the moment, it is difficult to solve the problem because the plane is designed to solve the problem only when it is on autopilot," Li said. "If manual operation is to disconnect the trim, the time must be fast, and if it is slow, it is difficult. The pilot starts to feel like he can't control his hands, and over time, it's too late to control them. So this problem, although there are some technical solutions, but can not fundamentally solve the problem."
After making relevant corrections, several air traffic control agencies, including the FAA and EASA in Europe, issued orders for Boeing 737MAX to go around. But the Civil Aviation Administration of China (CAAC) has taken a cautious view and ordered Boeing to conduct rigorous test flight approvals in China under the supervision of relevant parties.
In July 2021, Boeing sent 35 pilots and engineers to China; On August 4, a Boeing 737-7MAX (N7201S) took off from Seattle and arrived at Shanghai pudong Airport on August 7 after several stops. The Boeing 737-7Max landed at Boeing's Completion and delivery Center in Zhoushan Airport on August 11 to start test flight approval.
It is understood that China is currently the only country in the world that requires Boeing to send aircraft "across the ocean" for test flights. Previously, due to the epidemic and other factors, regulators in other countries and regions, are in Seattle and surrounding North America to conduct test trials.
Now, after nearly four months of test flight approval, the authorities have finally issued the airworthiness order. That means there are no legal hurdles for Boeing's 737MAX to return to service in China.
once the regulations allow, it will take months to prepare
Several regulators, including the FAA and EASA, have endorsed Boeing's modifications and approved the resumption of flights. After conducting a comprehensive review of the changes submitted by Boeing, the CAAC confirmed that the measures would eliminate the unsafe conditions.
