Date: 201604
Local time of day: 1801-2400
Location: DAL.Airport, TX
Flight conditions: Mixed
Weather elements / visibility: 10
Light: Night
Aircraft: 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 B DAL
ATC / advisory: Tower DAL
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Terrain Warning; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action
Contributing factors: Airport; Procedure; Weather; Aircraft
Primary problem: Ambiguous

Narrative: Prior experience; and DAL standardization info; led me to believe I would be landing on Runway 31L. Since the current ATIS had a 1;400 feet ceiling; I briefed the ILS to 31L. Past the airport; but prior to turning base; Regional Approach changed the landing runway to 31R. I was ready for this and quickly briefed the differences to include the tall buildings inside of the FAF; glideslope angle; ILS frequency; minimums; TDZE; and go-around procedure. All these were different from the 31L Briefing.After several heading changes; we received a 280 heading to intercept the Localizer inbound. I saw the heading would put us only 1/4 mile outside the FAF (DATLE). I knew that would be tight; but elected to continue. I armed the LOC; captured it; went to APP; and captured the glideslope; all within a few seconds. I felt the aircraft track the GS normally; and diverted my attention to set in zeros in the altitude window. I also had raw data called up for the ILS in the standby ADI and it looked normal. Just a few seconds from passing DATLE; I felt the aircraft increase its descent. The airspeed increased to 170 knots; forcing me to delay calling for landing flaps. During all this; we received a 'Caution; Obstacle'. Through a break in the clouds; I saw the tall buildings of downtown Dallas; heard the caution a second time; and performed a go-around. We went around about 1;800' MSL at F15 with a fluctuating glideslope. The last glideslope indication I saw was approaching two dots low. My First Officer (FO) told Tower we were executing a go-around and we were given go-around instructions. The altitude we heard was; 'maintain 1500' with a turn'. I did not want to descend; so I leveled off at about 2;000 feet MSL until we worked this out. Our go-around instructions were amended to climb to 4;000 feet and turn to 360 degrees. I cleaned up to F5 and had the FO input another ILS TO 31R. I told the FO to ask for a minimum of two miles; prior to DATLE for the intercept; but ATC did this anyway. The second approach was uneventful; and we picked up the airport at about 1;200 feet AGL. We then landed normally and taxied to the gate.ATC should not change the landing runway so late in an IMC approach. ATC should not vector us so close to the FAF to start an approach in IMC conditions. I know I should not ask for 31R but it seems ATC used it as much as 31L that night. We heard at least four AC to plan on 31R while we were talking to approach. The use of 31R in the DAL standardization info at night makes one think this will rarely happen. It was not the case that night. Better wording may be just 'ATC may assign runway 31R.'




Synopsis: Air carrier Captain reported becoming unstable inside DATLE after a late runway change and an intercept vector just outside DATLE in IMC. A caution obstacle is heard and a go-around is initiated. The second approach is successful.