United Airlines has announced that it discovered installation defects during inspections of the door plugs on its Boeing 737 MAX 9 jets, including loose bolts. This comes after a decompression accident occurred on an Alaska Airlines flight, where a door plug was blown away from the aircraft during ascent. As a result, United Airlines grounded its fleet of MAX 9 aircraft.
The discovery of installation defects significantly raises concerns for Boeing and its supplier, Spirit AeroSystems, which builds the aircraft fuselage and installs the plug. The Air Current, an industry outlet, reported that at least five United aircraft were found to have defects. Alaska Airlines, the other major U.S. airline operating the MAX 9 aircraft, has not yet begun inspecting its grounded aircraft to determine if similar defects exist.
In response to the incidents, the Federal Aviation Administration (FAA) issued an Emergency Airworthiness Directive ordering the inspections of all aircraft that were outside of certain routine maintenance inspection windows. Approximately 171 aircraft will be inspected out of the approximately 215 MAX 9 aircraft in service globally.
The decompression incident on the Alaska Airlines flight involved the left aft-wing “door plug” being blown out from the aircraft during ascent. The force of the decompression caused passengers’ smartphones to be pulled from their hands, opened the cockpit door, and ripped the pilots’ headsets off. Fortunately, there were no major injuries among the passengers and crew.
The 737 MAX 9 features a spot for an extra emergency exit, which is required for models of the aircraft with certain higher-density seating configurations. However, airlines with fewer seats, such as United and Alaska, choose to install a “plug” in its place. The plug is installed by Spirit AeroSystems, which manufactures the fuselage for Boeing’s 737 MAX aircraft.
The recent incidents bring back memories of the global grounding of the 737 MAX type that lasted nearly two years, starting in April 2019. The grounding was implemented following two fatal crashes involving the aircraft type. Investigators attributed the crashes to a flight control system called Maneuvering Characteristics Augmentation System (MCAS), which relied on a single “angle-of-attack” sensor. If that sensor became damaged, the plane could erroneously pitch down and cause the pilots to lose control.
Since the grounding, Boeing has faced scrutiny over its safety practices and records. Other potential manufacturing defects in various plane types, including the MAX, have been discovered. The recent findings highlight the need for thorough inspections and quality control measures to ensure the safety of aircraft and passengers.
In response to the groundings, both United and Alaska Airlines have cut flights, with United canceling approximately 200 flights and Alaska canceling about 140 flights. United expects significant cancellations through at least January 9, and Alaska is awaiting further information from the FAA before beginning the inspection process.
The aviation industry must prioritize safety and address any potential manufacturing defects to prevent accidents and ensure the trust and confidence of passengers. Thorough inspections and proper installation procedures are essential to maintaining the integrity and reliability of aircraft components. As the investigations continue, it is crucial for Boeing and its suppliers to address any issues promptly and implement necessary improvements to prevent similar incidents in the future.