CNN
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A United Airlines flight was discovered to be missing an external panel on the aircraft after it landed in Medford, Oregon, Friday afternoon after taking off from San Francisco, California, according to the airline.

The plane carrying 145 passengers and crew landed safely and was parked at the gate at Rogue Valley International Medford Airport when a person on the ground first noticed the panel was missing, United Airlines said in a statement.

The crew of Flight 433 did not declare an emergency and there was no indication of the damage during the flight, the airline said.

The aircraft is a Boeing 737-800, according to United. It is a previous generation and not the newer 737 Max aircraft recently making headlines.

United said the missing panel did not affect the flying characteristics of the airplane.

The missing panel was on the bottom side of the fuselage, underneath the wing and behind the main landing gear, United Spokesperson Leslie Scott told CNN.

Rogue Valley International-Medford Airport Director Amber Judd indicated to the Rogue Valley Times the aircraft is not in condition to fly and “will be here for a while.” Judd added it is unclear where the missing panel is.

“They don’t know where they lost it,” Judd told the RV Times.

United said it will “conduct a thorough examination of the plane and perform all the needed repairs before it returns to service.”

“We’ll also conduct an investigation to better understand how this damage occurred,” the airline added.

The Federal Aviation Administration said it will investigate the incident.

Operations at the Oregon airport were paused while a runway safety check was conducted after the flight landed safely around noon, Judd told CNN in a statement. “After finding no debris on the airfield, normal operations at MFR resumed a few minutes later,” Judd added.

The discovery of the missing panel comes as United faces scrutiny over a string of incidents with different aircraft, including an engine that ingested bubblewrap and caught fire midair, and another flight that lost a tire after takeoff.