EMB ERJ 170/175 ER/LR
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem
Procedure; Human Factors
It was the first flight of the day and it was my leg to fly. On the takeoff roll after rotation the airplane seemed like it was not climbing as well as it normally would. We received a momentary green PLI (Pitch Limit Indicator) and at that point both the Captain and I noticed something was not correct. After takeoff we looked over the numbers and realized that the takeoff was supposed to be a flaps 4 takeoff. This is an error that I have never made before; even after reading the documents that have come out on company stressing to be aware of the serious safety risks of doing a flaps 2 takeoff when it should be a flaps 4. This is an almost inexcusable error that I am very disappointed in myself for committing.After discovering this error I took a few minutes to think back on the events that may have caused it. Potential distractions or other things that happened causing an omission of this scale. Everything was very standard. The only explanation is that we both overlooked the flap setting on the MCDU and fell victim of routine. Taking off on 19 with a flaps 2 setting seemed very normal. If it had been Runway 15; a flaps 2 takeoff would have been a major factor in my mind. But because it wasn't; the flap setting didn't set off a red alarm in my mind. Looking back and considering our weight and distance to destination; it makes sense why this takeoff should have been a flaps 4. This is a critical error that I will never allow to happen again.When I look back on this event; I should have checked the numbers and verified and I should have checked for the flaps 4 setting in the MCDU. I also should have considered our weight and takeoff distance requirement. I also should have considered our low takeoff speeds. There were many factors to this; each one has allowed me to learn something and has taught me very important considerations to think about.
E175 First Officer reported incorrect flap setting on takeoff; resulting in reduced initial climb performance.