Airbus 318/319/320/321 Undifferentiated
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Time Pressure; Communication Breakdown; Confusion
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Executed Go Around / Missed Approach
Procedure; Human Factors; Environment - Non Weather Related; Airport
Had to go around on a visual approach to RW 27R in KPHL due to the aircraft in front failing to clear as quickly as I had expected.  We were cleared the visual approach after being told to proceed direct JALTO.  Prior to that we were on vectors with an assigned airspeed of 180KTs (approximately 4 miles from JALTO on a right base).  After being cleared the visual approach we seemed a bit tight on the proceeding aircraft so I slowed to 160 KTs 2 miles prior to JALTO and aimed about a mile outside the marker so as to make enough room.   All seemed fine as we had 2.5 miles spacing on the TCAS as I slowed to approach.  Normally 3 miles would be optimal on visual approaches but still it seemed we had enough.   As we were descending through 1000 AFL tower asked the proceeding aircraft (company) to clear at K4 however we heard no response from them on the radio.  Apparently they weren't able to make that exit as they continued down to T.  Tower asked them to expedite down to T as we were on short final by then (approx. 700 AFL I'd guess) but again we heard no response from the preceding aircraft.  At about 500 AFL tower directed us to go around which we did just as the aircraft was turning off at T.We had to go around for 2 reasons.  First of all I didn't recognize the tight spacing quick enough to give myself 3 miles....  that extra .5 miles would have made the difference.  However the secondary reason was that our company aircraft refused to respond to tower which raised doubt as to whether he/she would clear at T.  I have witnessed many pilots (including myself) become annoyed when tower calls them on the radio during landing since obviously it is a busy time.  That being said had they told tower that they would be off shortly then I'm certain we'd have been able to continue that approach to landing....  again we were not all that low at the time of the go around.... 500 AFL.At any rate it wasn't that much of a problem as we circled right back around and landed just a few minutes later.Personally I try to answer tower if possible when they call even during the landing.  The best example is when you land RW 04 in KLGA and the tower immediately asks you if you can make P or G.  Until you acknowledge with an answer they can't clear the aircraft on RW 13 for takeoff.  We have to work as a team with tower during that landing/departing configuration and I think a bit of teamwork could have been used on RW 27R the other morning as well.
An Airbus Captain executed a go-around on short final to PHL because the preceding aircraft was not clear of the runway; and failed to acknowledge ATC's request for an expedited runway exit.