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Alaska Airlines and United Airlines have now temporarily grounded all of their Boeing 737 Max 9s, including some aircraft they had previously returned to service with the belief that they would be in compliance with an emergency airworthiness directive (EAD) issued by the Federal Aviation Administration on Jan. 6.
Related: FAA orders temporary grounding of Boeing 737 Max 9s
The FAA issued the EAD following the in-flight departure of a mid-cabin door plug on Alaska flight 1282 on Jan. 5. It applies to approximately 171 model 737-9 airplanes with a mid-cabin door plug installed, and requires them to be inspected and all applicable corrective actions using a method approved by the FAA’s Continued Operational Safety Branch before further flight. The EAD does not provide further details on what such a method entails.
Prior to the publication of the EAD, Alaska had sent a memo to flight crew stating that 18 of its Max 9s had received a “thorough maintenance inspection” of the plug door as part of recent heavy maintenance checks using a method “written specifically for this task and provided to us by Boeing.” United had said that 33 of its 79 Max 9 aircraft had “already received the necessary inspection that is required by the FAA.”
Alaska and United operated these recently inspected Max 9s throughout the day on Saturday. Now both airlines have grounded all of their Max 9s pending clarity from the FAA on what is required.
“The 18 aircraft have been pulled from service until details about possible additional maintenance work are confirmed with the FAA,” Alaska stated. Likewise, United said it “has temporarily suspended service on all Boeing 737 MAX 9 aircraft to conduct inspections required by the FAA. We are working with the FAA to clarify the inspection process and the requirements for returning all MAX 9 aircraft to service.”
The National Transportation Safety Board on Saturday evening held its first formal media briefing, officially declaring Friday’s rapid depressurization an accident (rather than an incident), given the substantial damage to the aircraft. Chairwoman Jennifer Homendy said senior NTSB aircraft accident investigator John Lovell would serve as investigator in charge.
Lovell was previously the board’s representative to the years-long investigation into the March 2019 737 Max 8 crash of Ethiopian Airlines flight 302. The NTSB strenuously objected to aspects of the final report for that accident that triggered the worldwide grounding of the aircraft that stretched to the end of 2020.
On the Max 9 accident, Homendy said that she was “very encouraged…that the FAA took action to temporarily ground this particular aircraft for inspection and for addressing potential concerns that were identified through those inspections” but declined to “make any broad statements about the fleet” and its overall safety.
Exit in focus
Given both the tumultuous history of the Max and the manufacturing woes faced by Boeing the aircraft’s principal structural supplier, Spirit AeroSystems, the early focus and discussion centers on the manufacturing of the failed exit door on the brand new Max 9 involved in the accident.
Related: Boeing and Spirit grapple with newly discovered 737 Max quality issue
The fuselage for the accident Max 9 was loaded into Boeing’s systems integration tooling in Renton at the beginning of September, according to a person familiar with N704AL’s manufacturing, just as its factory was wrestling with the fallout from invasive inspections and rework on smaller 737 Max 8s. The aircraft completed two Boeing test flights and two customer acceptance test flights before its delivery to Alaska at the end of October.
The exit door goes through at least two rounds of quality assurance checks. One after the installation of the deactivated exit door on the fuselage in Wichita at Spirit. And again in Renton with Boeing to verify the door is flush, and the internal stop pins and hinges are correct. Once complete, Boeing closes out the area with sidewall and systems installation. The exit is not visible from inside the cabin in the configuration used by airlines who do not need more than 189 seats aboard the aircraft.
Confirming earlier reporting
Additionally, Alaska confirmed earlier reporting from The Air Current regarding both the pressurization issues experienced by the aircraft on Jan. 4., one day prior to the accident, and the airline’s decision to remove the aircraft from extended operations (ETOPS) flying.
A spokeswoman for the airline said, “These types of aircraft pressurization system write ups are typical in large aircraft commercial aviation operations. In every case, the write up was fully evaluated and resolved per approved maintenance procedures and in full compliance with all applicable FAA regulations.”
Homendy said the NTSB staff supporting the investigation included board experts in aircraft pressurizations systems.
Regarding ETOPS, the spokeswoman stated, “Out of an abundance of caution, Alaska Airlines has an internal policy to restrict aircraft with multiple maintenance write ups on certain systems, even when resolved consistent with FAA regulations, from flying ETOPS flights for a period of time. This internal policy is not required by any FAA regulation but is an additional ‘above and beyond’ safety precaution that Alaska Airlines voluntarily chooses to apply.”
