Date: 201507
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Aircraft component: Engine Starting System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Became Reoriented; Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: During our pushback the FO started number two normally. After the pushback had stopped and while I was in the process of clearing the pushback crew off; the FO got my attention and pointed to the N2 and EGT gauges. I saw 811 on the EGT and around 36% on the N1 gauge. He aborted the start and we accomplished the 'Aborted Engine Start' QRC and QRH before returning to the gate. We contacted Maintenance and wrote it up in the logbook. The one question we couldn't answer was how long the engine EGT was above 725. The aircraft was taken out of service and we got another one and proceeded on to [our destination] for the overnight. A management pilot paid us a visit after we were back at the gate and suggested we fill out a safety report describing the event. I called Chief Pilot to give him a heads up and have submitted the report.As the FO and I discussed the event later; several things struck me. He had never seen a hung start either on the line or in the simulator. I'm not sure any of our simulators replicate what seemed to happen during this start; a very slow increase in N2 and a corresponding ever increasing EGT rise. The FO seemed to have become mainly focused on the slow N2 increase after light off and thus missed the EGT as it approached the start limit. All this happened while my attention was devoted to the termination of the pushback and clearing the ground crew off.Since we have gone to our current start procedures; the Captain has largely been taken out of the loop during the engine start process with an emphasis to focus outside; manage distractions or maintaining control while taxiing during engine start. I feel if I had monitored the start closer; I may have been able to prevent this occupancy. Start malfunctions are very rare. I've only seen about a half dozen since I've been here. All were in an older model jet and all at high pressure altitude airports on days with the temperature near or above 100. This was the first hung start I've seen as low as the field elevation this time. As we all get less exposure to older model aircraft and less emphasis on older model training; we may see an increase in events such as these. It would help if we were able to provide more realistic training for this type of start malfunction with emphasis on how older model engines start so much differently than newer model aircraft.




Synopsis: During push-back; B737 crew experienced a hung/hot start while attempting to start engine number two. Crew was reassigned a different aircraft.