SUBSTANDARD WORK ON A BOEING? ONCE THAT WAS UNTHINKABLE. United Airlines found loose bolts, other issues on a key part of grounded Boeing 737 Max 9 jetliners.

United Airlines said Monday it found loose bolts and other “installation issues” on a part of some Boeing 737 Max 9 jets that were inspected after a mid-flight blowout on a similar Alaska Airlines jet on Friday.

The inspections are focused on plugs used to seal an area set aside for extra emergency doors that are not required on United and Alaska Max 9s.

“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,” Chicago-based United said.

Well, that inspires confidence. Plus:

The Boeing jetliner that suffered an inflight blowout over Oregon was not being used for flights to Hawaii after a warning light that could have indicated a pressurization problem lit up on three different flights.

Alaska Airlines decided to restrict the aircraft from long flights over water so the plane “could return very quickly to an airport” if the warning light reappeared, Jennifer Homendy, chair of the National Transportation Safety Board, said Sunday.

Homendy cautioned that the pressurization light might be unrelated to Friday’s incident in which a plug covering an unused exit door blew off the Boeing 737 Max 9 as it cruised about three miles (4.8 kilometers) over Oregon.

Hmm.