United Airlines confirms it found several Boeing 737 Max 9 aircraft with loose door plug bolts and related issues during inspections following a 5 January incident involving an Alaska Airlines aircraft of the same type.

“Since we began preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug – for example, bolts that needed additional tightening,” the airline says. “These findings will be remedied by our Tech Ops team to safely return the aircraft to service.”

Trade publication The Air Current initially reported that United found issues with the door plug bolts. Reports have said that at least five aircraft were affected.

When asked, United does not confirm that figure nor give further details about the anomalies.

United Airlines first 737 Max 9 flight

Source: United Airlines

United Airlines confirms it found ‘bolts that needed tightening’ on several of its Boeing 737 Max 9 aircraft

”Beginning on Saturday, United began preparing for these inspections by removing the inner panel to access the door plug and visually inspecting the area while awaiting final instructions,” the company says. ”To access each door plug, we remove two rows of seats and the sidewall liner. This has already been done on most Max 9s.”

The work involves inspecting and verifying proper installation of the plug and frame hardware, opening the plug and inspecting the area around the door and seal, and then re-securing the plug.

”Each inspection will include a team of five United technicians working for several hours on each aircraft,” United adds.

The carrier says it has had to cancel hundreds of flights since it grounded its 79-strong Max 9 fleet on 6 January, and “we expect significant cancellations on Tuesday as well”.

“We have been able to operate some planned flights by switching to other aircraft types, avoiding about 30 cancellations each on Monday and Tuesday,” the airline adds. On 7 January, United said it cancelled 270 flights over the weekend, and “saved” 145 flights by switching to other aircraft.

United operates more 737 Max 9s than any airline. Other operators include Alaska (65 examples), Copa Airlines (29), Aeromexico (19), Turkish Airlines (five) and Icelandair (four).

The FAA on 6 January issued an emergency airworthiness directive (EAD) requiring the inspections. The order applies to 171 aircraft globally.

The Alaska jet, with registration N704AL, was operating flight 1282 from Portland to Ontario, California at the time of the incident. The pilots safely landed the Max 9 in Portland, with only minor injuries to the 171 passengers and six crew members aboard.