The Federal Aviation Administration (FAA) has issued a proposed airworthiness directive calling for inspections of passenger seats on 453 Boeing 737 MAX aircraft, citing concerns over improper installation that could pose safety risks during turbulence or emergency landings. The directive, published Monday, targets 737-8 and 737-9 models and requires detailed inspections to verify that seat assemblies are correctly secured to their tracks.

According to the FAA, seats that are not properly installed may become detached under increased load conditions, potentially leading to passenger or crew injuries and obstructing aisles, which could delay evacuations. The directive affects roughly one-fifth of the more than 2,300 MAX jets currently in operation globally.

Boeing welcomed the FAA’s move to formalize its inspection guidance through a mandatory directive. The company’s latest quality concern comes shortly after the FAA reinstated Boeing’s authority to perform some final safety certifications on its newly built 737 jets—a privilege revoked in 2019 following two fatal crashes involving the MAX series. Since last year, Boeing has been gradually regaining this certification authority amid ongoing scrutiny.

The inspection requirement covers the three main MAX models in service worldwide, with estimated costs to U.S. operators of about $2.7 million before any necessary seat reinstallation expenses. The FAA action follows a series of safety challenges for the 737 MAX line, including a notable 2024 incident involving an incorrectly installed door plug that detached mid-flight from an Alaska Airlines jet. That event prompted a temporary grounding of dozens of 737s and a proposed civil penalty of over $3 million for Boeing related to safety violations.

Boeing is also seeking final FAA approval for two additional MAX variants—the smaller MAX 7 and the larger MAX 10—both of which have faced certification delays due, in part, to the company’s recent safety and quality control issues.

Separately, Boeing has faced scrutiny after a window blew off a 737 older variant during a Ryanair flight over Greece earlier this month, partially sucking a 61-year-old passenger out of the plane. The passenger survived, and the aircraft was diverted safely. This event echoes a similar window failure involving Southwest Airlines in 2018. The National Transportation Safety Board is currently involved in investigating the cause of the latest incident.