Date: 201808
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Takeoff / Launch
Aircraft component: Engine Starting System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Workload
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Environment - Non Weather Related; Human Factors; Procedure; Aircraft
Primary problem: Environment - Non Weather Related

Narrative: Flight had a write up that the previous crew was unable to start the #2 engine in ZZZ. After a 34 minute delay and two engine starts at the gate; we finally were on our way. The number one engine was started normally by FO (First Officer). The number 2 by manual start by Captain.We were planning on 18L and we were parked at terminal. We were given 17R which made it a shorter taxi. I; FO; was heads down changing the FCMU for the change of runway. The close out was tardy; I had to send a request for it. When the closeout arrived; I noticed and voiced that we were 3000 lbs. heavier than ATOW (Actual Takeoff Weight) but less than MTOW (Maximum Takeoff Weight) with the correct temperature. We were good for TOGA TO (Takeoff Go Around Takeoff) and the performance V-speeds. I was still doing a mental check. We did flight controls and the taxi checklist. I was a little behind in changing frequencies from Ground to Tower. When Tower clear us to position and hold. I asked the Captain are you good he said he was. I responded position and hold.I was still a little behind because I was still dotting my i's and crossing t's on the [system] in my mind but I thought I will have a moment to catch up on the runway. The Captain brought the thrust levers forward and continued for a takeoff roll. I stated 'we were position and hold'. He said: 'No; we were cleared for TO (takeoff)' I looked down at the airspeed 40kts. And truthfully; considered that I had missed the last clearance. Before I could say something else Tower cleared [us] for takeoff. I repeated the clearance; call 80 and took off uneventfully. I was so busy that I didn't realized how behind and rushed I was until I realized we almost took off without a clearance.


Second narrative: Our flight had a delayed departure because of maintenance on the aircraft ignition system. Starting the aircraft required a manual start checklist. This delayed us about 35 minutes. During taxi out Ground changed our departure runway and the FO (First Officer) made the change. After the change; she had to request a close out. The close out showed we were over our assumed takeoff weight. She elected to manually compute new takeoff data for TOFA (Takeoff Go Around) power takeoff. The normal taxi checklist was accomplished as we approached the runway. I thought I heard cleared for takeoff as we were running the 'below the line' part of the taxi checklist. I asked the FO if she was ready and she responded yes. We finished the checklist as we lined up on the runway and I elected to do a rolling takeoff. She asked me if we were cleared for takeoff as I selected TOGA power. I responded yes. Passing 60 knots tower cleared us for takeoff.I allowed us to get too rushed taxiing out especially with all the changes because we were late. I would recommend that if ACARS is working that any new takeoff data is requested from Dispatch. I will make sure we finish all checklist before we take the active runway.


Synopsis: A321 flight crew reported that takeoff clearance was not issued prior to start of the takeoff roll.