United Airlines has announced that it discovered installation defects during inspections of the door plugs on its Boeing 737 MAX 9 jets. These defects included loose bolts. This discovery comes after United Airlines grounded its fleet of MAX 9 aircraft following a decompression accident on an Alaska Airlines flight. The incident involved a door plug being blown away from the aircraft during its ascent for a flight. This finding significantly raises the stakes for Boeing and its supplier, Spirit AeroSystems, which builds the aircraft fuselage and installs the plug.
The Air Current, an industry outlet, was the first to report on the defects found by United Airlines. It stated that at least five United aircraft had been found to have these defects. On the other hand, Alaska Airlines, another major U.S. airline operating the MAX 9 aircraft, has not yet begun inspecting its grounded fleet to determine if similar defects exist. The airline is awaiting further information from the Federal Aviation Administration (FAA) before starting the inspection process.
In response to the decompression accident, the FAA issued an Emergency Airworthiness Directive ordering the grounding of certain 737 MAX 9 aircraft for inspection. The directive requires inspections for all aircraft that were outside of certain routine maintenance inspection windows, totaling approximately 171 aircraft. There are approximately 215 aircraft of this subtype in service globally, according to aviation data firm Cirium.
The decompression incident occurred during Alaska Airlines flight AS 1282, which was departing from Portland International Airport (PDX) en route to Ontario, California (ONT). As the aircraft continued its departure climb, the left aft-wing “door plug” was blown out from the aircraft, causing a rapid loss of cabin pressure. The force of the decompression was strong enough to pull smartphones from passengers’ hands, open the cockpit door, and rip the pilots’ headsets off. Fortunately, there were no major injuries among the 171 passengers and six crew members. The two seats next to the door plug were unoccupied, which was described as “very, very fortunate” by the NTSB chair Jennifer Homendy, who is leading the investigation.
The 737 MAX 9 includes a spot for an extra emergency exit, which is required on models with certain higher-density seating configurations. However, airlines that opt for fewer seats on the aircraft, such as United and Alaska Airlines, can 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 in Wichita, Kansas. The completed bodies are then shipped to Boeing’s Renton, Washington, factory for final assembly. The plugs are secured by just four bolts and other hardware, according to the NTSB.
Alaska Airlines operates 65 MAX 9 aircraft, while United Airlines has 79 of this type in its fleet. Both airlines have had to reduce their flight schedules due to the grounding, with United canceling approximately 200 flights and Alaska canceling about 140 flights. United expects significant cancellations through at least January 9, although it has been able to mitigate some of the cancellations by utilizing different aircraft types.
The discovery of these installation defects brings back memories of the nearly two-year global grounding of the 737 MAX following two fatal crashes. The crashes were attributed to a flight control system called Maneuvering Characteristics Augmentation System (MCAS), which was designed to pitch the aircraft down in certain situations. Investigators found that the system relied on a single angle-of-attack sensor, and if that sensor became damaged, it could cause the plane to pitch down erroneously and lead to a loss of control. Since the grounding, Boeing has faced scrutiny regarding its safety practices and records, and other potential manufacturing defects have been found in various plane types, including the MAX.
In conclusion, the discovery of installation defects on the door plugs of United Airlines’ Boeing 737 MAX 9 jets has raised concerns about the safety of these aircraft. The grounding of the MAX 9 fleet and the ongoing inspections highlight the need for thorough maintenance and oversight of aircraft manufacturing processes. It is crucial for Boeing and its suppliers to address these issues promptly to ensure the safety of passengers and restore confidence in the MAX aircraft.