Loose bolts found on five 737 Max 9 jets

United Airlines has found loose bolts on multiple 737 Max 9 aircraft, it said, referring to the Boeing model that has been grounded after a panel blew off an Alaska Airlines-operated plane in mid-flight over the weekend in Portland.

Industry publication Air Current reported that United found discrepant bolts on other parts on at least five panels that were being inspected following the accident. The inspections of 171 Max jets mostly operated by US carriers Alaska and United Airlines may take days, forcing flight cancellations.

The Federal Aviation Administration ordered checks of the 171 jets, installed with the 27-kilogram panel that detached from a full flight on Friday and crashed into a Portland suburb without harm.