The National Transportation Safety Board of the United States said on the 8th that the door plug (embedded emergency door) that fell off from the Boeing 737 MAX 9 aircraft that experienced an air accident on the 5th has been found, and the accident investigation is still ongoing. United Airlines announced on the same day that it discovered loose bolts while inspecting the same aircraft model.
A Boeing 737 MAX 9 aircraft of Alaska Airlines experienced an accident in the air shortly after takeoff from Portland, Oregon on the 5th, with a door stopper on the side of the cabin falling off. The plane immediately made an emergency landing without causing any casualties. Aircraft manufacturers sometimes use door plugs instead of emergency exits based on the configuration required by airlines.
Jennifer Hormendy, Chairman of the National Transportation Safety Commission of the United States, said at a press conference on the 8th that the focus of work now is to inspect the accident aircraft and the detached door plugs to determine the nature, cause, and preventive and remedial measures of the accident. Once a conclusion is drawn, further emergency measures will be taken based on the severity of the problem.
Homendi said in an interview that according to the crew's description, there was a very strong explosion at the time of the accident. External inspections showed that the aircraft had no structural damage, while non critical components such as the interior decoration, windows, and seats were damaged.
The aircraft involved in the accident experienced three instances of automatic pressurization malfunction lights turning on within a month. Homendi said that the repeated pressure increase alarms "made investigators very uneasy", but it is currently unclear whether there is a connection between the issue and the accident that occurred on the 5th.
The Federal Aviation Administration of the United States ordered a temporary suspension of Boeing 737 MAX 9 aircraft operated by American airlines or within the United States for safety inspections.
United Airlines issued a statement on the 8th stating that loose bolts were found on its 737 MAX 9 aircraft during emergency inspections mandated by the Federal Aviation Administration. "We have identified some issues that seem to be related to the installation of door plugs, such as the need for additional tightening of bolts." United Airlines did not disclose the specific number of loose bolts.
Boeing announced on the 8th that it has provided guidance to airlines and maintenance companies on how to inspect 737 MAX 9 aircraft. According to statistics, Boeing has delivered 218 737 MAX 9 aircraft worldwide, most of which are in service with Alaska Airlines and United Airlines.
Industry insiders say that this accident has intensified concerns about the quality control issues that have plagued Boeing for many years.