Narrative:

I gave aircraft X a clearance to cross the arrival fix at 11;000 feet and he already had a speed of 310 knots or greater. When he was around 15;000 feet he said he was reducing speed to 250 knots. I told him to maintain 300 knots. I asked him if it was an aircraft performance requirement. He said it was company policy to reduce speed to 250 knots at 11;000 feet. I told him we have a coordinated speed with approach to be at 11;000 feet and 300 knots and that he needed to maintain 300 knots. He said unable reducing speed to 250 knots due to company policy 'I can't help it'. I then told the supervisor; then coordinated the situation with chicago approach.there was an aircraft that was about 10 miles behind aircraft X at the time with the same crossing that I then needed to descend below aircraft X. As a result I read aircraft X the brasher warning and gave him chicago center contact information. I am not sure where it went from there. We have been having this problem for a while now with overseas pilots abiding by company policy and reducing speeds to 250 knots sometimes with no warning disregarding ATC clearances.I believe this is a big enough issue to look into oversees policies on this type of situation and correct it before someone loses separation or worse. Luckily I was slow at the time; but with a big enough trail into the airport a situation like this can cause us to now start vectoring because of an aircraft slowing without warning.

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Original NASA ASRS Text

Title: ZAU Center Controller reported a foreign air carrier refused to comply with a speed assignment.

Narrative: I gave Aircraft X a clearance to cross the arrival fix at 11;000 feet and he already had a speed of 310 knots or greater. When he was around 15;000 feet he said he was reducing speed to 250 knots. I told him to maintain 300 knots. I asked him if it was an aircraft performance requirement. He said it was company policy to reduce speed to 250 knots at 11;000 feet. I told him we have a coordinated speed with Approach to be at 11;000 feet and 300 knots and that he needed to maintain 300 knots. He said unable reducing speed to 250 knots due to company policy 'I can't help it'. I then told the Supervisor; then coordinated the situation with Chicago Approach.There was an aircraft that was about 10 miles behind Aircraft X at the time with the same crossing that I then needed to descend below Aircraft X. As a result I read Aircraft X the Brasher Warning and gave him Chicago Center contact information. I am not sure where it went from there. We have been having this problem for a while now with overseas pilots abiding by company policy and reducing speeds to 250 knots sometimes with no warning disregarding ATC clearances.I believe this is a big enough issue to look into oversees policies on this type of situation and correct it before someone loses separation or worse. Luckily I was slow at the time; but with a big enough trail into the airport a situation like this can cause us to now start vectoring because of an aircraft slowing without warning.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.