Narrative:

On the 4th leg of a long day during preflight; we missed properly setting the transponder during the preflight checklist. This was particularly odd since we paused at this point of the checklist item 'radios; transponder; and radar' to verify the departure frequency and altitude. I commented that I doubted that I'd previously flown that particular departure procedure. We stopped to verify the departure altitude and departure frequencies. The radar test had been accomplished earlier. Neither the captain nor I had requested the pre departure clearance via commercial radio and we both missed this item. It is my habit to set 3 zeros and a single digit in the transponder after every flight to remind the next crew that they don't have the transponder set. Since we had flown this plane in; the transponder read 'XXXX.' it wasn't until ground control queried if we had the correct transponder code set on taxi out that we realized we'd not received our pre departure clearance nor had put the correct code in. We stopped the jet safely on the taxiway; sent for the pre departure clearance; and were able to review the clearance together and set the transponder correctly without delaying traffic. We then departed normally without further known errors; three contributing factors - slight fatigue. We didn't think that having already flown 6 hours and 3 legs we were fatigued enough to compromise safety and checklist adherence. Second; complacency occurred from 2 very competent pilots flying together who trusted each other too much to catch minor items. Third; a couple recent changes in pre-departure and taxi procedures which essentially remove the first officer from being much help with situational awareness during the taxi created extra stress which led to an earlier conversation about the new policy. Apprehension about the new policy created a distraction during preflight preparations.

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Original NASA ASRS Text

Title: While taxiing for takeoff; ATC questioned a B757 crew about the transponder code and the crew then realized they had not gotten their PDC clearance and transponder code at the gate.

Narrative: On the 4th leg of a long day during preflight; we missed properly setting the transponder during the preflight checklist. This was particularly odd since we paused at this point of the checklist item 'Radios; transponder; and Radar' to verify the Departure frequency and altitude. I commented that I doubted that I'd previously flown that particular departure procedure. We stopped to verify the departure altitude and Departure frequencies. The radar test had been accomplished earlier. Neither the Captain nor I had requested the PDC via commercial radio and we both missed this item. It is my habit to set 3 zeros and a single digit in the transponder after every flight to remind the next crew that they don't have the transponder set. Since we had flown this plane in; the transponder read 'XXXX.' It wasn't until Ground Control queried if we had the correct transponder code set on taxi out that we realized we'd not received our PDC nor had put the correct code in. We stopped the jet safely on the taxiway; sent for the PDC; and were able to review the clearance together and set the transponder correctly without delaying traffic. We then departed normally without further known errors; three contributing factors - slight fatigue. We didn't think that having already flown 6 hours and 3 legs we were fatigued enough to compromise safety and checklist adherence. Second; complacency occurred from 2 very competent pilots flying together who trusted each other too much to catch minor items. Third; a couple recent changes in pre-departure and taxi procedures which essentially remove the First Officer from being much help with situational awareness during the taxi created extra stress which led to an earlier conversation about the new policy. Apprehension about the new policy created a distraction during preflight preparations.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.