Narrative:

Air carrier X appeared to be on a correct route of flight (on B753) when I took over the sector. It was only when he asked to show FL330 as his final requested altitude that I saw on user request evaluation tool (uret) that he was off course (he should have been direct kengs). At the same time; the receiving controller called to ask for control for turns direct kelpp and I said that I would clear him that way once I finished asking about the incorrect route he was flying. Air carrier X filed and was flying: 'kiah.VUH4.musyl..kengs./.saez' but was issued 'kiah.VUH4.vuh..kengs./.saez.' I asked the pilot to check and see which route he had been cleared because this route problem has become an ongoing issue and we hadn't found the source of the problem. I believe he replied that he had been given a verbal clearance of 'kiah.VUH4.vuh..kengs' but I'm not sure now. I cleared him direct kelpp (a fix southeast of kengs) and then switched him to the next sector. Air carrier X did not cause any separation issues with any other aircraft. While I told him the route error didn't cause me any problems; I failed to advise him that he may have been involved in a pilot deviation. After speaking with the pilot; I then advised my flm of the problem and we spent time on and off throughout the day to try to understand what the problem might be. I have heard of at least seven instances of this exact problem; most of the time it is happening with air carrier X; but not all. 1) the VUH4 SID was changed some time ago and all transitions were removed. The SID now shows radar vectors to vuh then the diagram shows a radial to musyl at which point the SID ends. However; the host computer issues a pdr which is different and may confuse pilots who are looking at the SID. The pdr issues 'VUH4.vuh..kengs...' after speaking with the airspace and procedures office; they said that the pdr needs to be changed to 'VUH4.musyl...' I recommend that the pdr be changed as the airspace office recommends until such time that the SID can be changed to reflect the way the controllers actually route the aircraft. The SID should have two transitions. 'VUH4.musyl..' and 'VUH4.kelpp...' 2) there is some question at the facility as to why so many aircraft are flying their filed route if/when they are being given a revised pdr. It is beyond my knowledge level to know exactly what the problem on the pilot's end could be. Is the revised pdr being missed by the pilots or is the FMS having a problem with the change? I recommend contacting someone who knows about FMS to examine any technical issues and contacting air carrier X to have them investigate from their side. 3) it is possible that there is a problem with clearance delivery. Today; my flm spoke with someone at the tower who listened to the tapes. The clearance issued did use our pdr and I believe the pilot read back the clearance. It is still possible that some of the other instances involve a problem with clearance delivery. This problem seems systemic in nature to me and I recommend alerting kiah tower; ZHU lake charles specialty; and air carrier X (and other airlines identified from other reports) that a special awareness be placed on these flights that request 'kiah.VUH4.musyl..kengs.'

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Original NASA ASRS Text

Title: ZHU Controller described a confused routing event involving an IAH departure assigned the VUH4 SID; noting the difference between the URET route and the aircraft track.

Narrative: Air Carrier X appeared to be on a correct route of flight (on B753) when I took over the sector. It was only when he asked to show FL330 as his final requested altitude that I saw on User Request Evaluation Tool (URET) that he was off course (he should have been direct KENGS). At the same time; the receiving Controller called to ask for control for turns direct KELPP and I said that I would clear him that way once I finished asking about the incorrect route he was flying. Air Carrier X filed and was flying: 'KIAH.VUH4.MUSYL..KENGS./.SAEZ' but was issued 'KIAH.VUH4.VUH..KENGS./.SAEZ.' I asked the pilot to check and see which route he had been cleared because this route problem has become an ongoing issue and we hadn't found the source of the problem. I believe he replied that he had been given a verbal clearance of 'KIAH.VUH4.VUH..KENGS' but I'm not sure now. I cleared him direct KELPP (a fix southeast of KENGS) and then switched him to the next sector. Air Carrier X did not cause any separation issues with any other aircraft. While I told him the route error didn't cause me any problems; I failed to advise him that he may have been involved in a pilot deviation. After speaking with the pilot; I then advised my FLM of the problem and we spent time on and off throughout the day to try to understand what the problem might be. I have heard of at least seven instances of this exact problem; most of the time it is happening with Air Carrier X; but not all. 1) The VUH4 SID was changed some time ago and all transitions were removed. The SID now shows RADAR vectors to VUH then the diagram shows a radial to MUSYL at which point the SID ends. However; the HOST computer issues a PDR which is different and may confuse pilots who are looking at the SID. The PDR issues 'VUH4.VUH..KENGS...' After speaking with the Airspace and Procedures office; they said that the PDR needs to be changed to 'VUH4.MUSYL...' I recommend that the PDR be changed as the Airspace office recommends until such time that the SID can be changed to reflect the way the controllers actually route the aircraft. The SID should have two transitions. 'VUH4.MUSYL..' and 'VUH4.KELPP...' 2) There is some question at the facility as to why so many aircraft are flying their filed route if/when they are being given a revised PDR. It is beyond my knowledge level to know exactly what the problem on the pilot's end could be. Is the revised PDR being missed by the pilots or is the FMS having a problem with the change? I recommend contacting someone who knows about FMS to examine any technical issues and contacting Air Carrier X to have them investigate from their side. 3) It is possible that there is a problem with Clearance Delivery. Today; my FLM spoke with someone at the Tower who listened to the tapes. The clearance issued did use our PDR and I believe the pilot read back the clearance. It is still possible that some of the other instances involve a problem with Clearance Delivery. This problem seems systemic in nature to me and I recommend alerting KIAH Tower; ZHU Lake Charles Specialty; and Air Carrier X (and other airlines identified from other reports) that a special awareness be placed on these flights that request 'KIAH.VUH4.MUSYL..KENGS.'

Data retrieved from NASA's ASRS site as of April 2012 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.