Date: 201407
Local time of day: 1201-1800
Location: IAH.Airport, TX
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower IAH
Aircraft component: FMS/FMC
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Time Pressure
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: Wrong RNAV departure transition selected after runway change. Originally we were filed for the BNDTO 1 departure JCT transition so that is what was printed on our release. However; our clearance was amended to the PITZZ 1 departure CRGER transition. We were unsure of the runway that we were to be assigned; so we input Runway 15R because the day before we were given the exact same scenario. The FMS was loaded correctly and verified to match the amended clearance prior to taxi. However; when we called for push back and advised Ramp Control of our assigned departure we were told to expect Runway 15L. Being a very studios First Officer; the non-flying pilot input Runway 15L however he selected the PITZZ 1 JCT transition. I was taxiing and looked down and verified the JCT transition against the release instead of the amended clearance. Therefore we now had the wrong transition loaded in the FMS with the correct runway.  After departure we were advised by ATC that we were tracking the wrong transition.One threat is that two different departures have the same name in the transitions. Another threat is that ramp control is advising crews of the runway to expect while taxiing. Therefore any changes to the FMS are done during a higher workload period such as taxiing. Some airports have RNAV departures that are runway specific and it is very important to input the correct runway. However; in Houston we would have been better off leaving the wrong runway in the FMS because the procedure is the same for both departure runways.In the future; I think I will cross out the amended clearance on the release and then write down the new clearance above the original filed route. Also; I think Clearance Delivery should include the expected runway for departure with the clearance. That way we can verify the flight plan while at the gate without the distractions of taxiing. I believe this is especially true at airports where the runway is very important for the departure flown; such as ATL. I understand that the runway may change after taxi out; however when this occurs ATC should recognize that we crew need time to make the changes without distractions.


Second narrative: Flight was given clearance in IAH for the BNDTO 1 RNAV departure (JCT transition); but was amended to the PITZZ 1 Departure (CRGER transition). The day prior; the exact same scenario occurred and the crew was assigned Runway 15R; so we therefore assumed we could expect the same Runway (15R) this day; which was then loaded into the FMS. However; during pushback the Ramp Controller assigned Runway 15L instead. During the high workload management time of pushback/engine start/taxi; the crew changed the runway to 15L in the FMS; but during this time incorrectly loaded the originally assigned transition (PITZZ 1.JCT); as opposed the newly amended transition (PITTZ 1.CRGER). This error went unnoticed until ATC noticed we were off course after departing the PITZZ intersection; when the aircraft began turning on the incorrect transition. ATC clarified the instructions; and the FMS was re-loaded and the aircraft resumed on its proper course.Due to the high workload management time of pushback/engine start/taxi; along with a short taxi time to the runway; the Captain and First Officer could have taken more time to cross-check FMS inputs and verify their correctness. When receiving an amended clearance or runway change; I will take more time to make sure the proper procedures are entered into the FMS; then cross-checking that with the Captain; charts; and any other source which would ensure accuracy. This may require delaying a taxi; or moving to a spot that's out of the way to allow for this to happen. The company should suggest that runway assignments are provided before the aircraft pushes back. At many of the airports we fly in/out of; runway assigned are often given while the aircraft is taxiing to the runway (at very busy airports); which allows room for errors; much like the one being reported; to occur. While I understand this may not be practical 100% of the time; being able to properly program and brief a procedure while the aircraft is stationary at the gate would significantly reduce the possibility of error.


Synopsis: Air Carrier flight crew reports a track deviation departing IAH on the PITZZ 1 RNAV. The SID was changed by Clearance Delivery prior to taxi and the runway was changed by Ground Control during taxi. When the SID is reentered into the FMC after the runway change the wrong transition is selected.