Date: 201212
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Circuit Breaker / Fuse / Thermocouple
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: First Officer
Human factors: Training / Qualification; Human-Machine Interface; Physiological - Other; Situational Awareness; Workload
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Flight Attendant
When detected: In-flight
Result: Flight Crew Took Evasive Action; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew FLC complied w / Automation / Advisory; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While in cruise at FL410; the #2 Transfer Bus Off light began to flicker and then the 'B' autopilot kicked OFF and the #2 Drive Light illuminated. We coordinated with ATC for a lower altitude while running the Drive Light QRH procedures. While running the QRH; we noticed an acrid smell in the cockpit followed by notification from the flight attendants of the same smell throughout the cabin. We then accomplished the QRH items for fumes in the cockpit and began to coordinate with ATC for an even lower altitude and request for diversion to a nearby airport. We also declared an emergency at this point and notified Dispatch and the flight attendants as well as getting the divert airport weather and getting performance calculations and getting out the appropriate approach plates and keeping the passengers informed as well as running the Descent and Before Landing Checklists. We coordinated for emergency response vehicles to meet us after clearing the runway to confirm there was no fire and that it would be safe to taxi to the gate. They cleared us to the gate and then the Captain contacted Dispatch/Maintenance Control/and Chief Pilot on Call after debriefing the emergency response crew. A logbook entry was made.


Second narrative: The next day; I followed up with Maintenance and they reported that the #2 GCU in the E&E bay was fried and the #2 Generator had also been replaced.Sometimes mechanical things break. I am not sure how to prevent that. The amount of time between the event; the decision to divert; and the actual landing was not long. Communication between the pilots; the flight attendants; and ATC was critical. We train in the simulator on a regular basis. The amount of information to process in terms of communication/coordination and checklists is dynamic and hard to accurately re-create for a time critical event in the real world. We were able to accomplish all required normal and non-normal tasks before landing. I can see how something like a fire immediately after takeoff would further complicate this scenario further reducing the time to respond to the event. In some situations; priorities will likely need to be decided and only the very essential tasks may be accomplished prior to landing the airplane. Please re-emphasize this in our training program.


Synopsis: A B737-700 #2 Generator Control Unit (GCU) and Generator malfunctioned in flight illuminating the #2 Transfer Bus Off and Generator Drive Lights as well as creating electrical fumes in the aircraft so an emergency was declared and the flight diverted safely to a nearby airport.