Date: 201601
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Night
Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Second aircraft: Small Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Situational Awareness; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; 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 New Clearance; Air Traffic Control Separated Traffic; Air Traffic Control Issued Advisory / Alert
Contributing factors: Procedure; Human Factors; Airspace Structure; Company Policy; Aircraft
Primary problem: Procedure

Narrative: I had to vector out Aircraft X on the arrival into ZZZ for spacing. I turned him back towards ZZZZ intersection and descended him to 14000 feet. I had taken a point out on a jump aircraft climbing up VFR to 13000 feet to drop jumpers near ZZZZ intersection. I had asked a controller to stop his aircraft at 16000 feet so I can get 2 arrivals down to 14000 feet. I pointed out an aircraft to the controller climbing out of ZZZ1. I gave Aircraft X cross ZZZZ intersection at 14000 feet (He read back 12000 feet garbled but readable on playback). While he was reading that back I noticed that the other sector had begun descending his [aircraft] to cross ZZZ VOR at 14000 feet. I immediately told him to stop that plane at 15000 feet (He apologized later). I noticed it took Aircraft X almost 10 miles to begin his turn to ZZZZ intersection. A few minutes later I saw Aircraft X data block update to 13800 feet. Next update was 13400 feet about 7 miles from ZZZZ intersection. I verified he was crossing ZZZZ intersection at 14000 feet. He said 'no; YOU cleared us to 12000 feet'. My clearance on playback was extremely clear and was ZZZZ intersection at 14000 feet. I issued a 30 degree left turn and climb to 14000 feet and issued the traffic 1 o'clock 10 miles a jump aircraft. 4 miles later I saw Aircraft X turning right to join the arrival. I told him I gave that 30 degrees prior to ZZZZ intersection to ensure distance between him and the jump aircraft who was now at altitude and jumpers could be in the air (currently Aircraft X was still below 13000 feet). I finally got prompt compliance from Aircraft X.These jump aircraft should not be allowed to drop on an arrival route into a major airport; or should be restricted to 11000 feet. The arrival descends to 12000 feet at ZZZ VOR. Also; I recommend this incident be 'pulled' and a Falcon Radar replay made to be distributed to the airline safety groups to show how lack of prompt compliance could lead to catastrophic problems.




Synopsis: An aircraft was issued a clearance to cross a fix at 14000 feet to avoid parachute jumping activity along its route at 13000 feet. The pilot readback 12000 feet. The Controller did not detect the erroneous readback.