Date: 201911
Local time of day: 0601-1200
Location: DTW.Airport, MI
Flight conditions: VMC
Light: Daylight
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E D01
ATC / advisory: TRACON D10
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Human factors: Communication Breakdown
Anomaly: ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Human Factors; Procedure
Primary problem: Ambiguous

Narrative: [The] flight had a possible pilot deviation on the BONZZ 2 arrival into DTW. PDC was 'cleared as filed' which included the KLYNK 3 arrival into DTW as well as the rest of the flight plan. I loaded the FMS per the company flight plan and all points and mileage were verified by the Captain prior to departure. Taxi; departure; and cruise were all uneventful. Prior to the arrival phase the Captain directed the review of the KLYNK 3 arrival and all points were dual verified.As the aircraft was directed to leave cruise altitude ATC cleared us direct to BONZZ by passing the majority of the arrival. This waypoint is also a fix on both the BONZZ 2 and KLYNK 3 arrival. Enroute to BONZZ we were given; 'Descend via the BONZZ 2 arrival landing north; expect Runway 22R.' I read back the clearance as the Captain set the bottom altitude for the KYLNK 3 arrival which I verified. ATC made no mention of any changes of or the use of an arrival other than our original clearance. Being that both arrivals shared the same points in the FMS neither pilot caught that ATC had changed our arrival. As the aircraft neared BONZZ ATC queried us as to our current altitude and what our charts said. ATC directed a level off at 11;000 feet and vectors. This was followed by being advised of a possible pilot deviation. Vectors continued until final for the visual to 22R. The remainder of the flight was uneventful.ATC detected the error and advised the generation of this report. Confusing directions from Air Traffic Control; extremely similar arrivals; and crew experience all played factors. Captain had only operated to this airfield 3 times with [the Company] and this was the first trip for the First Officer. ATC admitted they had assumed that we were familiar enough to know to alter our arrival due to the runways in use being different than the flight plan from the release. Aircraft was leveled and vectored to final. No incident or effect to flight operations. This incident could have been avoided with a single radio call from Air Traffic Control stating that we were no longer cleared for the KLYNK and now on the BONZZ arrival. Air Traffic Control was busy and this was a more workload heavy portion of the flight so when the FO read back 'cleared for the BONZZ arrival' while already proceeding direct to the 'BONZZ' waypoint both pilots incorrectly assumed that they were on the correct arrival. Upon closer inspection of the charts there was fine print also stating which arrivals were to be expected for which runways so pilot familiarity would have also aided in avoiding this possible deviation.




Synopsis: Air carrier First Officer reported ATC's arrival instructions were unclear regarding the SID in use out of DTW airport.