United Airlines finds loose bolts in Boeing 737 Max jets during inspections

Inspections took place after Alaska Airlines plane experienced gaping door hole during flight

A United Airlines Boeing 737 Max 9 jetliner is grounded at Luis Munoz Marin International Airport in San Juan, Puerto Rico on January 7. Reuters

United Airlines on Monday said it found loose bolts in Boeing 737 Max jets as it carried out inspections after a rival carrier’s plane suffered a structural failure.

“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,” the company said in a statement.

“These findings will be remedied by our Tech Ops team to safely return the aircraft to service.”

The planes are all recently built Max 9 models, the same version that suffered the earlier accident, a source said.

US aviation safety regulators grounded and ordered inspections for 171 Max 9 jets after a fuselage section blew out of a similar-vintage Alaska Air Group plane as it was climbing out of Portland, Oregon, on January 5.

No passengers or crew were injured during the accident, which left a gaping hole in the brand-new jet.

The findings by United heighten the urgency for operators of the Max 9.

Boeing on Monday issued guidelines to airlines on how to conduct inspections, an initial step before the US Federal Aviation Administration will approve a return to flight.