On Monday, United Airlines announced that loose bolts were found on multiple grounded 737 MAX 9 aircraft. This has raised the latest concerns among industry experts about the production method of Boeing's best-selling aircraft series, further deepening the crisis currently facing Boeing.
Last Friday, shortly after taking off from Portland, Oregon, USA, an Alaska Airlines Boeing 737 MAX 9 aircraft, an emergency hatch in the rear cabin suddenly fell off, causing the cabin to momentarily lose pressure and the plane to make an emergency landing.
After the incident, the Federal Aviation Administration (FAA) ordered a temporary grounding of Boeing 737 MAX 9 aircraft operated by American airlines or within the United States last Saturday to conduct safety checks on the aircraft.
Currently, there are only two American airlines operating the 737 Max 9, namely United Airlines and Alaska Airlines. Among them, United Airlines has 79 737 MAX 9 aircraft, making it the largest operator of this model.
United Airlines stated that its safety inspection found that bolts on multiple panels need to be tightened. This disclosure has heightened concerns about the production process of the grounded 737 MAX 9 aircraft.
"Since our initial inspection began on Saturday, we have identified some issues that seem to be related to the installation of cabin door plugs - such as the need for additional tightening of bolts," United Airlines said in a statement.
A source told the media that United Airlines has now found nearly 10 planes with loose bolts, and this number may continue to increase.
Boeing Crisis Deepens
Several industry insiders have stated that airlines have begun to hear passengers' concerns about the safety of the 737 MAX 9, although this problematic model is only used by a few airlines.
Any persistent concerns could increase the pressure on Boeing. After experiencing two major air disasters from 2018 to 2019, Boeing 737 MAX series aircraft were widely grounded worldwide for nearly two years. Boeing has been trying to address a series of quality defects in the past few years in an effort to regain public confidence in the safety of the 737 MAX series aircraft.
"The situation has undergone significant changes, as it is now a fleet issue or a quality control issue," said John Cox, an American aircraft safety expert.
"Starting from Friday night, it's really important to figure out if there's only one specific aircraft (with issues)," said Anthony Brickhouse, an aviation safety expert at Embry Riddle Aeronautical University. "United Airlines has now found some aircraft bolts to be loose, which means the scope of the investigation will expand."
The Federal Aviation Administration (FAA) stated in an email statement on Monday that Boeing 737 MAX 9 aircraft will continue to be grounded until operators complete enhanced inspections. The parts to strengthen maintenance include the left and right cabin door outlet plugs, cabin door components, and fasteners.
The safety check for the 737 MAX 9 aircraft is expected to last for several days, forcing a large number of flights to be cancelled. A senior industry insider stated that the duration of the inspections is becoming increasingly unpredictable, and the FAA, under the leadership of the newly appointed director, will be cautious about this accident.
Boeing's stock price fell 8% on Monday. Investigators said on Sunday that it is still too early to determine the cause of the accident.