Date: 201510
Local time of day: 0601-1200
Location: ZHU.ARTCC, TX
Light: Dawn
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZHU
Second aircraft: Widebody; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Oceanic
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Communication Breakdown; Confusion
Second reporter function: Oceanic
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure; Airspace Structure; Company Policy; Human Factors
Primary problem: Procedure

Narrative: I arrived at the same time as another controller. We received a briefing and he was working Ocean/Offshore sectors while I controlled the Domestic sectors. Shortly after taking the position I heard Aircraft Y ask if there was traffic at the same altitude in proximity to him. [The controller] informed him that there was traffic at FL380 feet on an adjacent airway. Aircraft Y was IPSEV.L207.SEAGL... and Aircraft X was (according to the flight strips and our knowledge) DUTNA.L208.PEGLG... These routes are parallel and non-RADAR separated. The controller asked Aircraft X to give his position from PEGLG and he responded that he was approximately 40 miles south of SEAGL. The controller asked him to verify his routing; to which he responded that he was cleared DUTNA..SEAGL.L207... The controller immediately descended Aircraft X to FL370 feet to establish vertical separation. The supervisor was notified right away.I can't begin to recommend a remedy to this problem because I can't figure out where the breakdown began. The flight plan information (strips) that we received from MMID center showed Aircraft X on L208; but he stated that [departure airport] issued him DUTNA direct SEAGL. The breakdown was somewhere between [departure airport] and MMID center.


Second narrative: I arrived at work and relieved the controller from the Oceanic and Offshore sectors. Shortly afterward Aircraft Y a non radar aircraft on L207 asked if we had crossing traffic at FL380. I informed him that the only other traffic I had at FL380 was an aircraft on the non radar airway L208 east of his (Aircraft X). At that point I asked the other non radar aircraft; Aircraft X to say his DME south of his next reported and filed fix PEGLG. Aircraft X informed me that he was 40 miles south southeast of SEAGL the next reporting point for the airway L207. I then asked Aircraft X to verify his position and routing. Aircraft X informed me that he was proceeding direct to SEAGL intersection. I then instructed Aircraft X to descend to and report reaching FL370. When Aircraft X reported reaching FL370 I asked him to verify his routing. He informed me he was cleared L208 to DUTNA direct to SEAGL. The filed routing we showed on Aircraft X flight progress strip showed his routing L208 DUTNA L208 PEGLG direct VUH then flight plan route; which is the approved non radar routing for Aircraft X's destination. I then asked Aircraft X who had issued him the incorrect routing that he was flying (L208 DUTNA direct SEAGL). The pilot informed me that the [departure airport] controller had issued him the routing upon his departure. A few minutes later we radar identified both aircraft.Check or double check the aircrafts next fix estimate when they check on over the Transfer Control Point fix from Center to Houston Center Oceanic Sectors.


Synopsis: Two aircraft at the same altitude were entering the ARTCC (ZHU) airspace on non-radar Oceanic routes. The flight plan information ARTCC had indicated the two routes were separated. One of the aircraft saw the other aircraft and asked the ARTCC about the traffic. ARTCC had the aircraft verify their route and realized one of the aircraft was on a different route than ARTCC had on the flight plan. The controller descended one of the aircraft to ensure separation.