Date: 201601
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Medium Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Conflict Airborne Conflict; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Rejected Takeoff; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Rejected takeoff event. There were multiple threats that contributed to this event. We were scheduled to deadhead on the last leg. The day before was 5 legs with a short overnight. Leaving on the second leg we taxied out Single engine to a run-up pad to wait for our wheels up time; about 40 mins. We had been previously delayed; and we were considering our Dead Head (DH) and length of day; we had some concern about missing the DH. About 30 mins into the wait for our wheels up the Flight Attendant (FA) called up to tell us a passenger was not feeling well because of a strong odor in the cabin of exhaust. Our engines were positioned close to a blast fence with a strong tailwind we assumed we were getting the smell because of this. We told the FA's we would move and to keep us informed on the passengers. We moved and the smell dissipated. The FA's said the passenger was better. We started the other motor and completed the taxi checklist. We were issued a clearance from tower to be ready and spooled up to take an expedited departure. The Captain (CA) advanced the throttles to 40% as we lined up. We were then cleared for an immediate takeoff. Traffic on approx. 2 mile final. CA advanced the throttles to toga; the AT did engage and advanced toward TOGA. As the Pilot Flying (PF) I am to confirm that the Thrust levers are at TOGA and ATTCS is green; confirming we are developing the thrust required for Take Off (TO). We did not achieve this criteria.I stated this to the CA that ATTCS was not in green; we were both looking at the gauge trying to ascertain what the problem was. We were not achieving the 81.5% required; only approximately 77.1%; as I pointed out the ATTCS the CA advanced the thrust levers; I thought he understood we were not accelerating properly and not developing the required thrust. About 2 seconds of confusion as we were ascertaining the situation. We received a ENG TLA NOT IN TOGA message (caution) and rejected the TO. We rejected approx. 3;000 feet and stopped approximately 4;000 down the runway. During the reject I told ATC we were rejecting and they told traffic to Go Around (GA). We cleared to runway checked the brake temps and the CA had me tell the Passengers 'remain seated'. We then determined the situation was stable; spoke with the FA's and returned to the gate. In my opinion we did the right thing. For some reason we were not developing needed thrust for TO; a tough thing to determine at 85-100 knots on a short runway. Not knowing; and ascertaining that the aircraft was unsafe or unable to fly the CA rejected below V1.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Air carrier crew responded to insufficient thrust warning during takeoff roll and rejected the takeoff.