EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
We pushed back and taxied without a problem. We were in line for departure waiting for the tailwind to be within limits. When the winds subsided Tower resumed departures; and we were then cleared for takeoff. I (Captain) said 'set thrust' the FO said 'thrust set.' At about 40 knots we got a EICAS Caution: Rudder SYS1 INOP. I (CA) say 'Abort Abort' and run the memory items. The FO makes PA 'Remain seated...' FO notified Tower and we taxied clear the runway on S4. We ran the applicable QRC/QRH. Then I (CA) called Maintenance. Maintenance instructed us on the applicable reset(s) and logbook items for the system at fault. After such time we re-sequenced in line for another departure. Again; cleared for takeoff; 'Set Thrust/Thrust set' 40 knots. Same EICAS Caution: Rudder SYS 1 INOP. We did exactly as above but this time decided it best to return to the gate for further Maintenance inspection. Dispatch did an aircraft swap and we continued on to our destination. Some of the threats encountered were having a tailwind; Flaps 18 takeoff.We performed the aborted takeoff and ran the appropriate checklists as trained by our training department.  If something like this were to happen again I think it would be prudent to hold the brakes and do a short run up to see if we would get the same message.
[This partial narrative added by Analyst as it contains additional information. Duplicate information that is contained in the Captain's report was omitted.]Threats on the takeoff: 8 knot tailwind; Flaps 18 ETO takeoff; taking off behind a heavy 757. Threats after the abort: The aborted take offs resulted in a duty day that exceeded 15 hours; we were then only received 9 hours of rest in which we had to submit this ASAP resulting in even less rest. Undesired aircraft state: Two low speed (around 40 knots) aborted take offs due to Rudder System 1 INOP. I feel the Captain and I performed well on the aborted takeoffs due to the training that we receive. They both [aborts] went relatively smoothly and were performed to standards. In the future; if I was presented with the exact same scenario I think that before commencing the second takeoff I would hold the brakes until thrust was set (since the anomaly occurred at this point during the previous abort.) This would allow us to see if the system was working properly before beginning the takeoff roll and subjecting the passengers to their second rolling aborted takeoff.
EMB-145XR crew had two sequential aborts at about 40 knots because of EICAS Caution of 'Rudder SYS1 INOP'. On the first abort the crew consulted the QRC and QRH; and then consulted Maintenance for guidance on procedures and log book entries. After the second takeoff attempt with the same warnings at about 40 knots; the crew decided to return to the gate and was issued another airplane.