Date: 201501
Local time of day: 0001-0600
Location: IND.Airport, IN
Flight conditions: IMC
Weather elements / visibility: Turbulence; Icing; 3
Light: Night
Aircraft: Widebody; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Initial Approach
Airspace: Class C IND
ATC / advisory: TRACON IND
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Time Pressure
Second reporter function: Relief Pilot
Anomaly: ATC Issue All Types; Deviation - Altitude Overshoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Weather; Procedure
Primary problem: Procedure

Narrative: We were cleared for the ILS23L; 3;000 FT until established and 180k to XEROX. At XEROX; still on approach; the controller issued the clearance 'XXX maintain 3000 FT and fly heading 140.' I initially didn't hear our call sign and thought it sounded like a clearance for another aircraft in the terminal area. After determining that the clearance was in fact for us a go around was initiated with the autopilot at first on and then disconnected; the turn to H140 was slow and altitude of 3;000 FT over shot by 550 FT.The clearance caused some level of confusion and delay since 'go around or discontinue approach' phraseology was not used by the controller. From that point better high altitude/approach and go around procedures and crew coordination were required in this situation. Better pilot/controller communication. Expecting the unexpected; with more thought given to go around procedures at a point other than minimums.


Second narrative: While on the ILS approach to Runway 23L at IND; the aircraft was descending through roughly 2600 FT on the Localizer and glide-slope (captured and tracking) autopilot was on. The Pilot Flying (PF) and Pilot Monitoring (PM) were discussing items relative to the approach when the Controller announced 'maintain 3000 FT fly heading 160.' No one seemed to hear it; except me; an Relief First Officer (RFO). While we were already below 3000 FT; it would be impossible to maintain something we had already passed through on the Glide-slope. Regardless; I asked PM; the First Officer to verify with ATC that those were indeed our instructions and that they were intended for us. PM at that point confirmed with ATC that those were our instructions. Never did I hear the terms cancel approach clearance or go around; perhaps those words were 'blocked'. Upon execution of the 'go around' we exceeded our clearance altitude.Improper; or non-standard phraseology during assignment of Go around/missed approach. Standard phraseology; probably would be a good idea to have controllers and pilots talk face to face from time to time; perhaps recurrent training or the like.


Synopsis: IND TRACON issued a go-around to an air carrier at 3;000 FT on approach to IND Runway 23L but the flight crew missed the command because of a nonstandard phraseology.