Date: 201406
Local time of day: 1201-1800
Location: DFW.Airport, TX
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 129
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B DFW
ATC / advisory: TRACON D10
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion; Communication Breakdown
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Procedure; Human Factors
Primary problem: Ambiguous

Narrative: While crossing ISABL and maintaining 11;000 FT MSL on the Glenn Rose Nine Arrival for Runway 18R at DFW; our head Flight Attendant informs me that our Number 3 Flight Attendant; who was stationed at the back of the aircraft; had complaints of ear aches. My response to her was that I will keep a low rate of descent for the rest of the flight and was confirmed that no medical assistance will be required for her once we arrived at DFW. Regional Approach (Freq.: 118.42) gave us a descent down to 5;000 FT and a downwind vector of heading 355 degrees for Runway 18R. While reading the Approach Checklist; Regional Approach requests to increase our rate of descent. I replied that it would be unable due to the aches that one of our flight attendants had with her ear. As a result of that; Regional Approach informed us to expect an extension on the downwind leg in order to conduct a low rate of descent (1;000 FT per minute) and requested us to fly 10 degrees to the left from the previous assigned heading.Flying abeam the final approach course for Runway 18R between YOHAN and LEGRE; Regional Approach using our call sign; gives the instruction to fly a heading of 150 degrees and to 'turn back' to the localizer for 18R and descend to 3;000 FT. Passing 40 degrees of azimuth direction to the right; Regional Approach queries about our turning and after informing the Controller that I read back to fly heading 150 degrees; since he used our call sign; he instructed us to fly a heading of 320 degrees to the left and descend to 3;000 FT; informing me that the 150 degree heading instruction was for another aircraft. At that moment and to avoid radio interference as well as lack of situational awareness; I decided that it was best not to argue with the Controller. After that; we received vectors for a visual approach to Runway 18R since the ILS was out of service as reported on the NOTAMs on ATIS Information 'Whiskey.'I would like to mention that while I was acting as Pilot Monitoring; prior and during the commencement of turning right to a heading of 150 degrees while in VMC; I kept close monitoring of our TCAS display in expanded mode which showed that we where not going to be in any conflict with nearby aircraft and did not receive any TA or RA advisories for that matter. No evasive maneuvers were required to turn to a heading of 320 degrees. Also; after our arrival at DFW; I did not receive any verbal or written notification from the authority with regards to the matter.My perception of what might have caused this problem lies with the subject of ATC phraseology. I recall that Regional Approach did not use the instruction to turn 'right' to a heading of 150 degrees. Instead; the Controller used the term 'turn back' with the instruction to fly a heading of 150 degrees and 'turn back' to intercept the localizer for Runway 18R. This put no doubt to me and the First Officer the Controller wanted a continuous right turn (shortest direction) to intercept the localizer since the runway was behind us at our 4 to 5 o'clock position and also because he extended the downwind vector to compensate for the low rate of descent that we needed.In order to prevent a recurrence; I believe that the direction 'left' or 'right' needs to be given when a heading is assigned by ATC since a pilot will assume that he or she will turn in the shortest direction of the given vector.




Synopsis: An aircraft on vectors to DFW Runway 18R with a slow descent rate because of a Flight Attendant ear block was given an extended downwind. During a subsequent vector; ATC used their call sign with a clearance meant for another aircraft resulting in a track deviation.