Late-night testing of the Boeing 777X engine Tuesday drew “numerous” noise complaints and violated airport policy, according to King County.

The aerospace giant was approved to perform engine run-up testing between 6 and 9 p.m., but Boeing didn’t begin testing until 9:30 p.m., according to a statement released Thursday from King County International Airport. The testing continued until 12:30 a.m. when airport operations staff contacted Boeing.

The airport says the testing also violated King County International Airport’s noise abatement policy, which restricts when certain activities can take place.

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Boeing told the county in a statement that the testing extended beyond the agreed time, and it apologized for disrupting residents.

“This was not a normal occurrence and we are making adjustments to prevent it from happening in the future,” the statement read in part.

Engine run-up testing of the 777X has been put on hold, and King County says it contacted Boeing leadership to ensure the incident won’t happen again.

The airport is considering holding a meeting to discuss the incident.