As it resumed flying the Boeing 737 MAX 9 yesterday, Alaska Airlines vowed to incorporate door plug inspections into its induction of any new MAX 9 delivered to the carrier.

“[W]e will inspect the door plugs on new 737-9 MAX aircraft we receive right after delivery,” assured Alaska.

This new door plug inspection for new MAX 9 aircraft is in addition to the inspections that take place “at least every 24 months when each plane undergoes heavy maintenance checks as part of our standard protocol”, the airline said.

On 5 January, Alaska began temporarily grounding its fleet of 65 MAX 9 aircraft, after one of the twinjets, registered N704AL, was forced to make an emergency landing at Oregon’s Portland International Airport due to a left-side, mid-cabin door plug blowout at roughly 16,320 ft.

A day later, the US Federal Aviation Administration (FAA) issued an emergency airworthiness directive (EAD), grounding 171 MAX 9 aircraft with a mid-cabin door plug installed. United Airlines, with 79 MAX 9s, was also affected by the EAD.

During in-house inspections, both Alaska and United discovered loose door plug hardware on some of their MAX 9s, which helped to inform the FAA’s corrective action.

Armed with data from 40 inspections of grounded aircraft, the FAA on 24 January approved a detailed set of inspection and maintenance instructions for affected operators. The enhanced maintenance process requires:

• An inspection of specific bolts, guide tracks and fittings
• Detailed visual inspections of left and right mid-cabin exit door plugs and dozens of associated components
• Retorquing fasteners
• Correcting any damage or abnormal conditions

After completing final inspections on its first group of MAX 9 aircraft, Alaska resumed flying the aircraft type yesterday afternoon with Flight 1146 from Seattle to San Diego. It expects inspections on its MAX 9 fleet to be completed by the end of next week, allowing it to operate a full flight schedule.

“We remain extremely grateful to our skilled Maintenance and Engineering team that is shouldering the inspection work and safely returning the planes to service, along with gratitude to all our employees who continue to help support our guests,” said Alaska.

As for passengers who are reluctant to fly the MAX 9, the airline has a Flexible Travel Policy in place through 31 January for guests to make other travel arrangements.

For its part, United today began pressing its inspected MAX 9s into service.

“As we always do, we’ll continue to work closely with Boeing and the FAA to make sure our entire fleet is reliable and, above all, safe. With that in mind, we are sending inspectors to the Boeing facility in Renton, Washington to provide input on Boeing’s processes,” said United CEO Scott Kirby in a LinkedIn post.

Meanwhile, the FAA is investigating Boeing and has ramped up oversight of the US airframer, saying the 5 January MAX 9 incident “must never happen again”.

The FAA has also informed Boeing that it will not grant any production expansion of the MAX, including the MAX 9, until it is satisfied that quality control issues are resolved.

Related Articles:

• Alaska and United discover loose door plug hardware on some MAX 9s
• NTSB begins probe of Alaska MAX 9 blowout amid grounding
• Alaska Airlines temporarily grounds 737 MAX 9s after mid-air incident
• Will you fly the 737 MAX? Even some aviation enthusiasts are hesitant
• Comparing American Airlines 737-800 and MAX 8
• MAX grounding shows aviation must nurture its corporate Cassandras

Featured image credited to Ingrid Barrentine/Alaska Airlines