Date: 201904
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Rejected Takeoff
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: After lining up on Runway XX at ZZZ and cleared for takeoff; the First Officer rapidly advanced throttles to takeoff power without pausing at 1.05 EPR/50% N1. Realizing the error; the First Officer pulled the thrust lever back toward idle and saw 50% N1 on the number 2 engine and again pushed throttles to TOGA (Takeoff Go-Around). I saw the number 1 engine was still at or close to idle and rejected the takeoff due to the asymmetric thrust and hard left turn. I got the aircraft under control and directed First Officer to tell Tower we were rejecting the takeoff. We cleared the runway and I called for the rejected takeoff checklist. We fully debriefed what went wrong and commenced a normal takeoff.First Officer stated that in a previous job of 10 years they would just push the power up and go. Also; upon landing in ZZZ1 I was able to fully debrief all 3 flight attendants. I am a (high minimums) Captain. The First Officer did make the 'Remain Seated' call which I found out later. I didn't hear the call to the passengers because of the headset the First Officer was wearing; which I think is a huge safety issue that needs to be addressed.


Second narrative: It was my takeoff. The Captain aligned the aircraft with the runway. We were clear for takeoff and he said; you have the aircraft I'm off the brakes and tiller. I responded; I have the jet; clear for takeoff. I immediately advanced the thrust levers forward way past 50% N1 but not all the way to takeoff power; when I realized my error of not stabilizing the engines at 50% N1. I went back to idle. When I looked at the engines again; they were now at 50% N1 so I advanced them forward again thinking they were stabilized now; but that is when the aircraft veered to the left of centerline. I immediately went back to idle and tried to align the aircraft by applying full right rudder. Simultaneously; the Captain applied brakes and said 'I have the aircraft; tell Tower we are aborting.' I told Tower 'Aborting takeoff Runway XX.' Got on the public address and said 'remain seated' twice. We exited the runway and ran the aborted takeoff checklist followed by FMGC initialization after a rejected takeoff. We told the Tower the reason for aborting was unstable engine thrust. We got back on line and performed a normal stable takeoff with a smooth flight and landing into ZZZ1.


Synopsis: A319 flight crew reported rejecting a takeoff after incorrectly applying takeoff power by not allowing engines to stabilize first.