Narrative:

We were taxiing out to the runway; single-engine; with the APU off. Near the departure end of the runway; the left engine generator tripped. We followed the non-normal checklist for elec gen off left; which allows for only one reset of the generator. We reset the generator. After a few minutes; the generator tripped again; but this time it was accompanied with an automatic left idg disconnect. We followed the non-normal checklist associated with the idg disconnect; and backed up the automatic disconnect by pressing the idg disconnect switch per the checklist. We returned to the gate.maintenance notified us that they planned on deferring the left engine idg. Captain said that he was fine flying our pacific ETOPS flight with an idg inoperative; making reference to the MEL. I was not comfortable with the decision; and expressed my concern to the captain. So did the other first officer. I felt that having a primary source of electrical power unavailable to us would be a degradation of safety; and referred the captain to the regional equipment guide in the manual; which states: 'the following table lists equipment that is considered operationally sensitive for flights in specific regions. This equipment is deemed highly desirable to maintain the proper level of safety for operations within these challenging areas.......' if one refers to the table it shows; 'electrical: two engine & APU ' with a 'U' in the pacific column. The 'U' denotes equipment that is; 'highly desirable for flights in the specific region.' taking an aircraft with an inoperative idg over a 2;500 mile overwater ETOPS segment with no alternates available along the route did not seem like a prudent path to me. We would be departing a major maintenance base with an inoperative generator and two first officers who would be uncomfortable in that situation. After discussing the potential threats of the situation with the captain and the other first officer the captain made it clear that he was going to depart with the inoperative idg. I then decided to remove myself from the flight. The other first officer also removed himself from the flight.

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Original NASA ASRS Text

Title: B777 flight crew experienced a generator trip during single engine taxi out and reset the generator. A few minutes later the generator trips again. The flight returns to the gate where Maintenance decided to MEL the IDG. The Captain accepts the aircraft as MEL'd for this ETOPS flight but the First Officers do not and remove themselves from the flight.

Narrative: We were taxiing out to the runway; single-engine; with the APU off. Near the departure end of the runway; the left engine generator tripped. We followed the non-normal checklist for ELEC GEN OFF L; which allows for only one reset of the generator. We reset the generator. After a few minutes; the generator tripped again; but this time it was accompanied with an automatic left IDG disconnect. We followed the non-normal checklist associated with the IDG disconnect; and backed up the automatic disconnect by pressing the IDG disconnect switch per the checklist. We returned to the gate.Maintenance notified us that they planned on deferring the L engine IDG. Captain said that he was fine flying our Pacific ETOPS flight with an IDG inoperative; making reference to the MEL. I was not comfortable with the decision; and expressed my concern to the Captain. So did the other First Officer. I felt that having a primary source of electrical power unavailable to us would be a degradation of safety; and referred the Captain to the Regional Equipment Guide in the manual; which states: 'The following table lists equipment that is considered operationally sensitive for flights in specific regions. This equipment is deemed highly desirable to maintain the proper level of safety for operations within these challenging areas.......' If one refers to the table it shows; 'Electrical: Two Engine & APU ' with a 'U' in the Pacific column. The 'U' denotes equipment that is; 'highly desirable for flights in the specific region.' Taking an aircraft with an inoperative IDG over a 2;500 mile overwater ETOPS segment with no alternates available along the route did not seem like a prudent path to me. We would be departing a major maintenance base with an inoperative generator and two First Officers who would be uncomfortable in that situation. After discussing the potential threats of the situation with the Captain and the other First Officer the Captain made it clear that he was going to depart with the inoperative IDG. I then decided to remove myself from the flight. The other First Officer also removed himself from the flight.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.