A United Airlines Boeing 737 Max 9 aircraft lands at San Francisco International Airport on March 13, 2019 in Burlingame, California.
Justin Sullivan | Getty Images
United Airlines said Monday that it has found loose bolts on door plugs of several Boeing 737 Max 9 planes during inspections spurred when a panel of that type blew off during an Alaska Airlines flight at 16,000 feet last week.
The Federal Aviation Administration on Saturday grounded dozens of 737 Max 9s after the panel blew out midflight on Alaska Flight 1282, calling for inspections.
United has 79 of the Max 9 planes in its fleet, and is the biggest operator of the jet model.
“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,” United said in a statement. “These findings will be remedied by our Tech Ops team to safely return the aircraft to service.”
Plane manufacturer Boeing said earlier Monday it issued instructions to airlines to conduct the inspections of the Max 9s in their fleets. United had begun some preliminary inspection work in the past few days.
Alaska Airlines, which is also inspecting its planes, didn’t immediately comment. Aviation publication The Air Current first reported that United had discovered the loose bolts.
This is breaking news. Check back for updates.
This story originally appeared on CNBC