Date: 201507
Local time of day: 0601-1200
Location: ORD.Airport, IL
Weather elements / visibility: Rain
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Mission: Passenger
Flight phase: Takeoff / Launch
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload; Distraction
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Ground Event / Encounter Ground Strike - Aircraft; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: For our flight we were assigned and followed taxi instructions from ground control to taxi to 28R for an intersection takeoff. We had followed proper procedure and had proper weights and takeoff data for 28R for the current weather conditions. Initial takeoff data for weather at the time of the start of our taxi called for a flaps 5 takeoff.Before starting the taxi the Captain asked for a full power takeoff because there was heavy rain at the time. This seemed like a prudent decision. I deleted the reduce thrust setting on the N1 takeoff page in the FMC and then loaded in the full power V speeds on takeoff page 1 in the FMC. We completed the after start flow and check and we then started our taxi out.Weather conditions in ORD were variable wind and heavy rain during our taxi out. There was a lot of ground traffic and taxi instructions were very complicated. We were approximately number 15 to depart and slowly moved up in the line. During our long taxi out I noticed the wind had shifted to a tailwind and I thought it prudent to get new takeoff data for 28R. I requested the data and it loaded in promptly. I checked the new takeoff data weather information and it matched the current outside conditions. Winds were reported to be 120 at 8; giving us an approximate 8 knot tailwind component. Because of the additional tailwind component the new takeoff data called for a flaps 10 takeoff. I advised the captain I had requested new takeoff data and briefed the new information. I also advised him it was now a flaps 10 takeoff. He called for flaps 10 and I set it.  I also advised him that I deleted the reduced thrust setting and inputted the max thrust takeoff V speeds into the FMC.I was the flying pilot. After a long taxi out to takeoff we were cleared for takeoff from 28R. By the time we actually took off the weather had mostly cleared and the runway was now dry. The takeoff proceeded normally. During rotation I noticed the aircraft pitched up a little faster than normal. I quickly arrested the pitch rate back to a normal rate. I noted an aircraft pitch angle of approximately 6 to 8 degrees as the main wheels lifted off the ground. Later on during cruise flight I looked up our takeoff pitch angle in the 'Pitch Report' function. It stated 6.6 degrees; which I felt was a fairly normal angle for takeoff. There were no abnormal sounds during takeoff and the flight attendants did not report any strange sounds during takeoff either. Although the pitch rate during the very first moment of rotation was a bit high; the actual takeoff pitch attitude was normal and I never suspected a tail-strike situation. Although; I know there is a higher risk of a tail-strike with a tailwind component. Later in flight; I thought it was a possibility we did not have the correct takeoff trim setting for our actual takeoff. Although the captain and I both verified the trim setting during our after start procedure; because we received new takeoff data with a new flap setting; the trim setting most likely changed. I inadvertently forgot to verify this new setting after getting new takeoff data for our new weather conditions.There is currently no checklist when getting new takeoff data. Although; I am usually very good double checking all of our settings and numbers; and always try to follow company procedures to perfection; I missed this setting on this particular flight. The weather was poor during taxi; the captain was somewhat unfamiliar with Chicago taxi procedures; there was a lot of ground traffic (airplanes and vehicles) around our aircraft all the time; and the taxi procedures were complicated. My attention was focused on helping us taxi to the right place; at the right time; without hitting anything. I tried to split my attention effectively; stay appraised of our new weather; and get new takeoff data when it was needed.




Synopsis: B737 First Officer reported taking off from ORD with the stabilizer trim incorrectly set because of distractions.