Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Returned To Gate; Flight Crew Rejected Takeoff
Aircraft
While finishing our preflight; we were waiting for the last bags to be off loaded in the forward cargo. After the ground crew finished; we entered the final takeoff data. The Forward Green Trim band was showing. The Takeoff CG was 22.1% on the load sheet with a Stab Trim setting of 3.3 on the FMC. That trim setting was just above the Mid Band Indication and into the Forward Green Band. We continued with our checklist and began to Taxi to Runway 03. After being cleared for Takeoff; I pushed the thrust levers forward to around 65% N1 and allowed all 4 engines to stabilize. I released the brake pedals and pushed Take off go around. As soon as I did the; 'CONFIG WARNING' sounded and I immediately disconnected the Auto-throttle and pulled the thrust levers to idle. The indicated speed was around 40KTS. The FO (First Officer) was pilot monitoring and advised me that it was a Stab Trim CONFIG Warning. I advised the Tower that we aborted the Takeoff and advised them we would need to return to the ramp. The FO advised the deadheading crew members to remain seated. After we exited the runway; I noticed the Forward Green Band was no longer there. The FO informed the crew members that we had to go back to the ramp. I entered the Low Speed Rejected Takeoff due to Stab Trim CONFIG into the logbook. The Maintenance onboard the aircraft advised me that we should try to move all crew bags from the bulk cargo to the forward. After moving the bags we could still not get a Forward Green Band. Maintenance performed checks on the system and all passed. I decided that it would be prudent to have more fuel added to attempt to get the Stab Trim in the Middle Green Band. After discussing this with Dispatch and Maintenance Control we agreed this would be the best solution. After adding fuel and getting a new load sheet; we entered the new performance data. Once again; the Forward Green Band showed. However; this time our Stab Trim setting was inside the Middle Green Band. I looked back down to check the trim band again and noticed the Forward Green Band was gone again. We double checked the data again and made sure everything was entered correctly. Since the performance data was correct and the Stab Trim was now just inside the Middle Green Band; we decided to continue. A normal Takeoff was accomplished.There has been some instances of crews reporting changes in the Stab Trim settings after the performance data was put in the FMC. However; this time was not one of those instances. I believe the nose strut moved after we released the brake and the system removed the Forward Green Band. After returning to the blocks; I had the [numbers rerun] to make sure we were given the proper Take off CG numbers. He did notice a slight change from 22.1% to 22.3%. Negligible difference to say the least. The trim given by the FMC originally was 3.3 units. That was the same as when we entered the blocks. Since this is a Passenger aircraft and it has been in service for quite some time; I believe it would be prudent to have it weighed and a new [RON work] calculated. This is the only thing I can think of why the aircraft system is removing the Forward Green Band because we are starting from a point in the weight and balance that may be incorrect now.
Flight Crew aborted a takeoff after receiving a Stab Trim CONFIG Warning during the takeoff roll.