B737 Undifferentiated or Other Model
Flight Crew Last 90 Days 187; Flight Crew Type 8700
Distraction; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Rejected Takeoff
Human Factors; Weather
First push was on time. Significant delay occurred waiting for first deice attempt. Another aircraft was being deiced and was experiencing radio problems communicating with deice truck. Eventually; we were deiced; but had to relay communication through Ops radio (no direct communications with truck. Instead; handheld radios in truck were used to talk to Ops and then Ops to us). While we were being deiced the first time; the previously deiced aircraft returned saying he needed more deicing.Eventually; we assumed we were complete with the deicing due to the 'thumbs up' we saw from the bucket Crew. We tried to get a radio confirmation of clean aircraft status from deice truck; but still no radio contact. After; radio calls to Ops; they relayed to us that the Deice Crew stated we were clean.Between the first aircraft returning for additional deicing and the lack of direct radio communication; we decided the safe course of action would be to do a cabin check before takeoff to confirm we had a clean aircraft. Cabin check was made and frozen precipitation observed on cabin side of both engine nacelles. A call to Ops was made to return for additional deicing.We were deiced a second time. We did another cabin check and the aircraft still had frozen precipitation in the same locations. Because of the extended ground time; we taxied back to gate.Once the situation was sorted out about which passengers would continue and new releases were issued; we pushed back for another deice procedure. We had spoken with the Supervisor at the gate to make sure they knew where the problem areas were on previous deice attempts. They said an experienced crew would do deice procedure. They also requested we trim the aircraft full nose down trim for deice. As our procedure calls to deice in the green band; we had aircraft trimmed as far forward as possible; but remain in the green. This did result in having to 'note' the trim setting not being in the proper setting in the Before Push Checklist. We stated this fact and mentioned the need to reset the trim after deicing.This time; we decided to do a cabin check at the point of deicing; rather than taxi to runway. The cabin check was done by both the Captain and the First Officer to leave no doubt about what was seen; since once again; we did not have a clean aircraft. Another call was made to Ops to deice again. Engines were shut down and we again described the location of the snow/contamination. The Captain was requested and made a multi-party phone conference with the [a dispatch manager]; Dispatch; and the ABQ Station Manager to discuss the issue and to make sure all involved parties knew precisely what needed to be done to have a clean aircraft and safe flight.This fourth and final deice procedure was conducted with radio communication directly with deice truck. They did a double check of each problem area and stated they could see there was no contamination. The Captain did a cabin check and confirmed it resulted in a clean aircraft.Post-Deicing Checklists were done and we were finally at departure end. As this was an older model aircraft; autothrottle and LNAV preselection are not used. I dinged the Flight Attendants and we ran the Before Takeoff Checklist. I have tried to run through the situation after the fact to recall whether I did throttle check after dinging the Flight Attendants. I thought I had; but might not have done; the lack of the normal reaching up to arm the autothrottle may have been a factor. Or perhaps I was intent on hearing the Flight Attendant state we were 'finally' cleared for takeoff after nearly four hours on the ground and four deice procedures.We were cleared by Tower for takeoff and I taxied slowly onto runway due to ice/snow present and 'braking fair' reports by other aircraft. After lining up the plane and confirming the runway; I gave control of the thrust levers to the First Officer. As he advanced the thrust levers; we got a TakeoffWarning horn. I took control of the aircraft and quickly determined with a scan of the various takeoff configuration items that the trim; although it looked in the front edge of the green; was clearly not in the takeoff setting per the [computer] and was the source of the horn.We told Tower we needed to clear the runway and would like to taxi back to try another takeoff. We trimmed to the proper setting. I did a throttle burst check with no horn. We ran the Before Takeoff Checklist and were cleared for and flew a normal takeoff.We should have been more proactive when we accommodated the request by the Deice Crew to set a trim other than the takeoff setting. Writing trim in big letters on back of ATIS card and displaying prominently; for example. The throttle burst should have detected this though; but I am not sure if I did or did not do one. The trim was set at the forward edge of the green band and may have been on the edge between triggering the horn.
[Report narrative contained no additional information.]
A B737 flight crew reported considerable difficulty getting the aircraft properly de-iced before departure; and as a result of the distraction; they began the takeoff roll with the trim mis-set.