Narrative:

It started with an inoperable tug (stuck in 'crab' mode) and a delay due to the challenge of moving inop tug; jet bridge; and inserting new tug in tight gate situation.after pushback into alley; first officer (first officer) noticed the right inertial reference unit (IRU) was not aligned (very rare). Due to traffic in alley; we attempted an incomplete alignment while we waited; but were unable to complete. Turned rt IRU off and taxied out.coping with the always challenging ground ops; we got to a position between rwys 27L & right where we accomplished the 5-6 min successful alignment of the rt IRU. We returned to the take off (to) flow and were cleared position and hold.a 757 took off in front of us & given heading 230 off of RW27L. We were given immediate to clearance even before the 75 had lifted off? (Never seen this in 31 years; a creative phl op?). Another distraction. Told tower we were going to wait for 2 min for wake turbulence.upon application of to power; got to warning horn & realized that to flaps were not set. Corrected to flaps 1; and continue to with our incident.airborne; the first officer stated that both of us had verbalized the to flaps checklist item. I truly do not remember this. I am normally hyper meticulous about 'calls for 1; I see 1; 1; green light' while pointing to associated items.obviously; a classic case of stringed distractions leading to a breakdown in checklist discipline on the crew's part.

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Original NASA ASRS Text

Title: Boeing 737 flight crew reported of being in position and cleared for takeoff behind a B757. Captain advised ATC they wanted 2 minutes. After two minutes they started takeoff and realized they had not set the flaps correctly. Flaps were configured and takeoff continued.

Narrative: It started with an inoperable tug (stuck in 'crab' mode) and a delay due to the challenge of moving inop tug; jet bridge; and inserting new tug in tight gate situation.After pushback into alley; First Officer (FO) noticed the Right Inertial Reference Unit (IRU) was not aligned (Very rare). Due to traffic in alley; we attempted an incomplete alignment while we waited; but were unable to complete. Turned RT IRU off and taxied out.Coping with the always challenging ground ops; we got to a position between RWYs 27L & R where we accomplished the 5-6 min successful alignment of the RT IRU. We returned to the Take Off (TO) flow and were cleared position and hold.A 757 took off in front of us & given heading 230 off of RW27L. We were given immediate TO clearance even before the 75 had lifted off? (Never seen this in 31 years; a creative PHL op?). Another distraction. Told tower we were going to wait for 2 min for wake turbulence.Upon application of TO power; got TO Warning horn & realized that TO flaps were NOT set. Corrected to Flaps 1; and continue TO with our incident.Airborne; the FO stated that BOTH of us had verbalized the TO Flaps checklist item. I truly do NOT remember this. I am normally hyper meticulous about 'Calls for 1; I see 1; 1; Green Light' while pointing to associated items.Obviously; a classic case of stringed distractions leading to a breakdown in checklist discipline on the crew's part.

Data retrieved from NASA's ASRS site 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.