Bolts requiring “additional tightening” have been identified during inspections of Boeing 737 Max 9s, according to United Airlines.
United Airlines mentioned that “installation issues” related to door plugs would be addressed before the aircraft type resumes service.
Inspections were initiated following an incident where a segment of the fuselage detached from an Alaska Airlines 737 Max 9 on Friday.
Alaska Airlines reported discovering “some loose hardware” on certain Max 9s since then.
The Federal Aviation Administration (FAA), responsible for air travel regulation in the US, has grounded 171 planes of the same model.
United stated, “Since we commenced preliminary inspections on Saturday, we have found instances that seem to be related to installation issues in the door plug – for instance, bolts that needed additional tightening.”
The door plug, a fuselage piece with a window, fills the space where an emergency exit would be in specific configurations.
This part of the Alaska Airlines plane detached mid-flight over the US state of Oregon, landing in a teacher’s backyard.
An emergency landing was executed, with no serious injuries to passengers or crew.
The National Transportation Safety Board revealed that the plane’s door plug was found without the four bolts.
The majority of Boeing 737 Max 9s in the US are operated by United Airlines and Alaska, with Turkish Airlines, Panama’s Copa Airlines, and Aeromexico also grounding the same model for inspections.
United mentioned cancelling 200 flights as of Monday, with expectations of significant cancellations on Tuesday.
Alaska Airlines reported initial findings of “some loose hardware” on their Max 9 fleet, emphasizing thorough inspections following formal procedures provided by the FAA and Boeing.
The FAA issued a checklist for operators to follow during inspections, keeping all 737 Max 9 aircraft grounded until enhanced inspections and corrective actions are completed.
Flight 1282, involved in the incident, descended from 16,000ft (4.8km) on Friday evening, revealing a hole in the craft’s side and deploying oxygen masks.
The US National Transportation Safety Board reported pressurization warning lights on three previous flights of the specific Alaska Airlines Max 9 involved.
The NTSB chief mentioned restrictions on long-haul flights over water due to these warnings, though the connection to the recent blowout is unclear.
Alaska Airlines said its 737-9 Max fleet’s grounding has significantly impacted operations, with numerous flight cancellations.
Boeing expressed regret for the impact on customers and passengers, emphasizing safety as a top priority.
The 737 Max faced heightened scrutiny after two crashes in 2018 and 2019 caused by flawed flight control software, resulting in 346 fatalities.
