So-called door plugs on another Boeing model are facing inspections under a “safety alert” issued by US air regulators.
The Federal Aviation Administration (FAA) recommended early on Monday that airlines operating Boeing 737-900ER jets ensure the parts are properly secured after some operators reported unspecified issues with bolts.
The work was carried out in the wake of the mid-air scare aboard a packed Alaska Airlines flight earlier this month that saw the door plug fall out, prompting 171 737 MAX 9 planes to be grounded for checks.
The 737-900ER has the same door plug design.
It allows for the addition of an extra emergency exit door when carriers opt to install more seats.
In its “Safety Alert for Operators”, the FAA said that inspections “noted findings with bolts” and all users should check the four bolts used to secure the door plug to the airframe “as soon as possible”.
Like with the 737 MAX 9s, Alaska and United are the largest users of the 737-900ER aircraft and neither airline expected to cancel any services as a result of the checks being carried out.
No 737-900ER planes operate in the UK.
A Boeing spokesperson said of the FAA alert: “We fully support the FAA and our customers in this action.”
The 737 MAX 9 blowout reignited concerns over safety at the US manufacturer as it sought to rebuild confidence following two fatal crashes involving MAX variants – in 2018 and 2019.
Ryanair boss Michael O’Leary, Boeing’s largest customer in Europe, was among top figures in the industry to raise concerns about quality control at the manufacturer.
He told Sky News last week that passengers were safe in its MAX 8 planes.
On Wednesday, the FAA said inspections of an initial group of 40 Boeing 737 MAX 9 jets had been completed, a key
hurdle to eventually allowing the planes to fly again.
The regulator added that it was continuing to review data from those inspections but said the MAX 9 will “remain grounded until the FAA is satisfied they are safe to return to service”.