The US airline regulator has ordered the temporary grounding of some Boeing 737 Max 9 jets after an outer section of one of the planes fell off during an Alaska Airlines flight.
The Federal Aviation Administration (FAA) said the inspections would affect 171 airplanes.
On Friday, the Alaska Airlines flight had to make an emergency landing in the US state of Oregon.
The plane, carrying 177 passengers and crew, landed safely in Portland.
In a statement, the FAA said it would order the temporary grounding of certain Boeing 737 Max 9 aircraft operated by US airlines or in US territory.
Required inspections will take around four to eight hours per aircraft, it said.
The Alaska Airlines flight to Ontario, California, had reached 16,000ft (4,876m) when it began its emergency descent, according to flight tracking data.
Images sent to news outlets showed the night sky visible through the gap in the fuselage, with insulation material and other debris also seen.
Boeing is urging airlines to inspect its 737 Max airplanes for a possible loose bolt in rudder control systems.
The airplane maker called for the inspections after an international operator discovered a bolt with a missing nut, the Federal Aviation Administration (FAA) said. An airplane’s rudder is used to control the aircraft while in flight.
“The issue identified on the particular airplane has been remedied,” Boeing said.
“Out of an abundance of caution, we are recommending operators inspect their 737 Max airplanes and inform us of any findings. We informed the FAA and our customers and will continue to keep them aware of the progress.”
The FAA said it was “closely monitoring targeted inspections of Boeing 737 Max airplanes to look for a possible loose bolt in the rudder control system”.
Boeing has recommended that the checks – which take only about two hours – happen within the next two weeks. (BBC)
Any problems involving a faulty rudder would likely be identified in a pre-flight check, as crews routinely examine the rudder system before flying, Boeing said. (BBC)
