Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9.0
Communication Breakdown; Confusion
ATC Issue All Types; Airspace Violation All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic
Aircraft; Human Factors
Aircraft X was in conflict with another aircraft at 36000 feet. I queried the second aircraft if they were able higher altitude to cross; they replied unable 38000 feet but could accept 37000 feet. I then asked Aircraft X if they were able 38000 feet. The response was heavily accented and sounded like 'Able 380.' I asked to confirm; they then said what sounded like 'Standby.' A moment later; I heard what sounded like 'Unable 380.' I then climbed the crossing aircraft to 37000 feet. A couple minutes later; I noticed Aircraft X radar target had changed to a FREE track. I asked what fix they were proceeding to; they replied 'We're heading 280.' I became puzzled as to why and then cleared them to a fix on their route. They made their initial turn in the confines of the previous sector; but I did not notice that maneuver until they were in my airspace.I reviewed the tape and was able to then decipher what they said when I initially asked if they could 'Accept FL380 for crossing traffic;' they replied with '[garbled] heading 280.' I spoke with the Operations Manager to see if a Brasher notification was needed; but he said 'No; we should have caught that.'Readback/hearback is to blame. Heavy foreign accent is contributory. [Recommend] Fast-track Datalink/CPDLC. There is an increasing number of foreign flights operating in US airspace. Voice communications are becoming more problematic and readback/hearback errors of this nature could end badly. Most; if not all; long-haul airliners are equipped for CPDLC; as is NavCanada and Eurocontrol. If we want to maintain the safest system in the world; we need to adopt appropriate safety technologies.
ZMP ARTCC Controller asked an aircraft if they could accept a climb clearance to 38;000 feet. The responses were misunderstood by the Controller due to the pilot's foreign accent. The Controller noticed the aircraft turned to a 280 degree heading. The aircraft was still in the previous sectors airspace so the turn was not coordinated.