Date: 201303
Local time of day: 0601-1200
Location: PHL.Airport, PA
Flight conditions: VMC
Weather elements / visibility: 5
Light: Daylight
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Flight phase: Taxi
ATC / advisory: Tower PHL
Second aircraft: Commercial Fixed Wing
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Human factors: Communication Breakdown
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Ground Incursion Runway
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued New Clearance
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: We were taxiing slowly off of the ramp on Taxiway U and received at ATC clearance from PHL Tower. The Tower clearance was: 'Air Carrier X taxi straight ahead; cross Runway 27L hold short south side of Sierra'. The First Officer read back the clearance to Tower and there was no correction to his read back transmission. Both of us heard a runway crossing clearance although it was using non-standard ATC phraseology. We did not ask for a clarification as we felt we both knew what we were cleared to do. At this time; I checked the CDTI and saw an Air Carrier that was holding on the runway. I noted that the Air Carrier did not have his lights on for takeoff at this time. There was another radio call that may have distracted us from hearing a takeoff clearance for the other Air Carrier; but we never heard a takeoff clearance for that Air Carrier on 27L. Prior to crossing 27L; we then heard PHL Tower tell the other Air Carrier to 'cancel takeoff clearance'; and then he notified us that we were not cleared to cross the runway. We immediately stopped and then Tower told us to continue to cross the runway. We told them that we heard our clearance as 'taxi straight ahead; cross Runway 27L hold short south side of Sierra'. This was non-standard; but that is what we tried to mimic. In hindsight; we should have queried the Tower Controller because the clearance did seem non-standard but both of us felt that we did understand what he said.


Second narrative: While holding short of Runway 27L at Uniform off of the ramp; ATC cleared us 'Taxi straight ahead cross 27L and hold short on south side.' The Captain and I understood this clearance to cross 27L and hold short on the south side of Taxiway Sierra. A ramp call may have distracted us from hearing a clearance for an aircraft holding in position on Runway 27L prior to crossing Runway 27L we confirmed the Air Carrier holding in position and verified that his landing lights were not illuminated indicating he was not on takeoff roll. Prior to entering Runway 27L; ATC cancelled the other Air Carrier's takeoff clearance. At this time we saw the landing lights illuminate. We never heard a takeoff clearance issued to the other Air Carrier. PHL Tower queried us about our clearance and said we were supposed to hold short. I replied 'Negative sir we were cleared to cross 27L and taxi straight ahead.' I believe the taxi clearance we received did not use standard ATC phraseology. If the Tower Controller's intent was for us to hold short of Runway 27L he did not clearly state 'Hold short of Runway 27L on Uniform' I should have recognized this and queried the Tower using standard phraseology as well. Both I and the Captain believed that our clearance was to cross Runway 27L. I believe I read back the clearance the way it was received.


Synopsis: Air Carrier described a runway incursion event resulting in an ATC directed aborted takeoff clearance; the reporter indicating confusion with ATC's clearance.