Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Aircraft; Company Policy; Human Factors
After pushing from the gate; I called for taxi clearance and was told our clearance had dropped out of the system. As a result the captain made the decision to shut down the number one engine to conserve fuel while coordinating with dispatch to refile and waiting to receive the new clearance from ground. After receiving the new clearance I completed a delayed engine start per the Operating Manual (OM); and we taxied to the runway for takeoff. During the takeoff roll; around 80 KIAS the captain; who was PM; stated that the engines were not putting out symmetric thrust. I could not notice the difference in the feel of the aircraft; and stated such; so we continued the takeoff. After calling for the after takeoff checklist the captain told me that the engines both went to normal climb thrust when the thrust levers were put into the climb thrust detent.After discussing the issue; the captain and myself both agreed that the issue was that we forgot to input the flex thrust value from the weight and balance after completing the delayed engine start; after the number one engine had already been started and shut down prior to the delayed engine start. I did not recognize the difference in the thrust carrots while completing the before takeoff check below the line and the captain did not initially notice the difference in thrust when stating thrust set during the takeoff roll. While shutting an engine down after starting both is not unusual; it is not very common. Since we already completed the after start and performance checklists; and there was no change requiring the completion of another performance check; we did not complete an additional performance check after completing the delayed engine start. Additionally; while we did not feel rushed; we were significantly delayed due to maintenance and a scheduled aircraft swap. I missed the difference in thrust carrots during the before takeoff check. Slow down and be vigilant when completing checklists. The company could bring this scenario to the attention of pilots.
On takeoff roll; we set thrust and I viewed the N1 gauges noting the carats and arrows were lined up. On looking back through my scan; noticed that the two engine N1 gauges were different colors and that they were producing asymmetric thrust (takeoff on the left side and flex on the other). I mentioned this to the First Officer and he mentioned that it felt like a crosswind to him. At this point we were past 80 KIAS and I opted to continue as it was safer to do so. I asked him to compensate for the asymmetrical thrust through to the after takeoff check when we would set climb thrust. He had it well under control. Once the settings were complete in the after takeoff check; symmetric thrust was established.We had many threats to our operation today. We had a mechanical failure on our first leg that resulted in a gate return and ship swap. Then we were subsequently delayed waiting for our aircraft. As we arrived in airport ZZZ; we had to swap again and then we were quite a bit behind; sort of hurrying to right the schedule.Once we pushed back and called for taxi (after the after start and performance checks) we were told our flight plan had dropped out. It was at this time that we had to shut the engine down to conserve fuel while we spoke to dispatch and ATC to get a new flight plan. Once the flight plan was refiled and ATC could reissue the clearance; we began taxi and restarted #1 completing a delayed engine start procedure. Then; of course; we missed the N1 setting in the before takeoff check and then noticed the difference only after setting thrust and well into takeoff roll. The error directly leading to the undesired aircraft state.I learned a great deal from this. If I am stopped at the gate and awaiting a clearance; I could scan things and check the N1s. After the delayed engine start; again; I should check the N1s. We hadn't completed another after start or performance check; so we let the procedure lead us into this state; from now on my scan will include the N1s in every phase. Feels like a sort of trap to get myself out of every time there is an engine shutdown on taxi out. I will remain vigilant in the future.
CRJ-700 flight crew described the circumstances leading to a takeoff with one engine programed for takeoff thrust and the other set to flex thrust. The number one engine is started then shut down due to an ATC delay. When the engine is restarted the flex thrust temperature setting is not reentered.