A321 flight crew reported that first flight of the day the number 2 engine was slow to spool.

Attributes
ACN	1576967
Time
Date	201808
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A321
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 22000
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

On clearance for takeoff; first officer; pilot flying; set initial power setting to %50 N1. He didn't like how slowly one engine was accelerating to %50 versus the other one so he pulled the throttles back to idle. Since this was a rolling takeoff we had no choice at that point but to reject. So we cleared off the runway. As the captain with 2;000 hours in this aircraft I didn't see that the delay between engine accelerations was all that abnormal. So we talked about letting the engines stabilize at %50 with brakes set on our next takeoff. We got back in line and re-ran all the checklists. On takeoff we left the brakes on while setting %50. Engine accelerations were normal so we went on our way.

Original NASA ASRS Text

Title: A321 flight crew reported that first flight of the day the Number 2 engine was slow to spool.

Narrative: On clearance for takeoff; First Officer; Pilot Flying; set initial power setting to %50 N1. He didn't like how slowly one engine was accelerating to %50 versus the other one so he pulled the throttles back to idle. Since this was a rolling takeoff we had no choice at that point but to reject. So we cleared off the runway. As the Captain with 2;000 hours in this aircraft I didn't see that the delay between engine accelerations was all that abnormal. So we talked about letting the engines stabilize at %50 with brakes set on our next takeoff. We got back in line and re-ran all the checklists. On takeoff we left the brakes on while setting %50. Engine accelerations were normal so we went on our way.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.