Date: 201507
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Taxi; Takeoff / Launch
Aircraft component: APU
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Time Pressure; Distraction; Confusion; Communication Breakdown; Training / Qualification
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Overcame Equipment Problem; Flight Crew Rejected Takeoff; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Aircraft; Manuals; Procedure
Primary problem: Human Factors

Narrative: Aircraft was dispatched with MEL [for an] Engine generator systems (IDG; GCB) RH INOP; requiring use of APU to power right side electrics. Although the procedures applicable to this MEL were thoroughly briefed; after pushback First Officer (FO) inadvertently selected APU to off per habituated normal procedures. Captain caught it almost immediately and returned the APU switch to RUN. The APU continued it's normal shutdown cycle because the switch was not placed to START then RUN. Although the MEL was completely understood and briefed; neither pilot caught that the APU had shutdown because they thought they had intervened in time by returning the APU switch to RUN. As well; during taxi out to the runway; no EICAS or panel lights alert that the affected electrics are not being powered by the APU nor that the APU has shutdown. The only way to ensure that the affected electrics are being powered by the APU is to verify PRIOR to takeoff that the APU RUN light is illuminated. No existing procedures guarantee nor mandate that this critical action is accomplished.During initial power application for [Takeoff (TO)]; both Utility busses auto load shed as a result of the right side electrics being unpowered. Aircraft speed never exceeded 10 knots and a slow speed reject was performed with the aircraft being taxied off the runway to an unoccupied taxiway. Corrective actions were taken by restoring the APU and a normal TO followed.Inadequate systems training and reinforcement of systems knowledge; operational application; during initial training. The brevity of systems training and lack of operational application does not provide crews with an adequate back-stop of experience when faced with non-normal situations.Additionally; during preflight no preliminary W&B was delivered to the aircraft. The Final W&B was delivered approximately 3 minutes prior to scheduled pushback. The lateness of the W&B created a feeling of being rushed; which ultimately led to the FO habituating to normal after takeoff procedures.Standardize procedures for operations with MEL's. Although the After Start Checklist includes RECALL and the Pilot Handbook (PHB) discusses unexpected EICAS messages; it was insufficient in this instance to prevent the event as the two EICAS messages encountered were anticipated and expected. If RECALL were placed earlier in the checklist; in this case prior to APU; the expected EICAS messages; and then appropriate follow-on action (APU on versus shutdown); would have been more easily facilitated. Additionally; procedures requiring crews with MEL's to discuss EICAS messages prior to calling for the After Start Checklist could help alleviate this kind of event.In addition; the MEL should be modified to include an additional Operations step.PRIOR TO TAKING THE RUNWAY FOR TAKEOFF; ENSURE APU RUN LIGHT IS ILLUMINATED


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


Synopsis: A B767 flight crew rejected the takeoff due to EICAS warnings resulting from mistakenly shutting down the APU after dispatching with a generator inop.