Date: 201209
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet CL65; Undifferentiated or Other Model
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: Generator Drive
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Human factors: Communication Breakdown; Situational Awareness; Training / Qualification
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: The issue for which I am filing this report was a disagreement over the nearest suitable airport between me and the Captain. With exception to the approach; I was the pilot flying and the Captain was the pilot monitoring. The flight began normally until climbing through about 7;000 FT; IDG 1 shut off with a associated 'GEN 1 OFF' EICAS caution message. As per the QRH we reset the generator and it remained off. Also as per the QRH we started the APU and continued to destination. Some time later; when we were approximately 80 miles north northwest of destination and over ZZZ the 'APU OIL TEMP' message displayed. We completed the QRH procedure for this message. The procedure was thus: 1. 'Is APU GEN required? If no; shutdown APU. If yes; land at nearest suitable airport.' Since we were already down to 2 of our 3 generators; the appropriate course of action was to land at the nearest suitable airport. Once finished reading the QRH; the Captain declared that the nearest suitable airport for us at that time was our destination. My first reaction was that the APU OIL TEMP message suggested that the APU was overheating and therefore was a possible fire hazard. With this in consideration; I concluded that the nearest suitable airport was ZZZ; which happened to be practically right underneath us. I verbally suggested to the Captain that I believed ZZZ was our nearest suitable airport since it was closest (and certainly suitable). The Captain disagreed; and suggested that our destination was the nearest suitable for a couple reasons. Captain reasons were: We were already on the decent to destination. ZZZ may be just below us but since we were at FL280; the time between the two airports would be similar. The reason the QRH instructions are to land is in case the APU shuts down leaving us with 1 generator. However; since the weather was perfect and flying on 1 generator isn't hazardous; and an emergency decent into ZZZ wasn't appropriate. Captain said that either (I can't recall which) a. That the QRH said that we would lose nose wheel steering once the APU shuts down upon landing or b. that Captain knew that we would lose nose wheel steering once the APU shut down upon landing. Captain said that since there was a possibility of losing the nose wheel steering [Captain] preferred the much longer runway at our destination (+3;000 FT). I was still not persuaded that our destination was the most suitable airport because:Captain's point comparing the descents into the two airports I considered plausible. I was vaguely associating the hot APU with a possible fire; and thus the NEAREST airport would be most suitable regardless. I was aware that nose wheel steering is only necessary for sharp turns and is not needed for directional control. Therefore the length of any runway would be irrelevant. Although I was not convinced; I did not disagree strongly enough to take further action because:I mostly agreed with the Captain's assessment of the two descents; and did not think a emergency decent was necessary. This was considering the weather; and with exception of the two messages; normal APU; engine; and electrical indications.Partially because of vague memory and partially because of what the Captain said; I at the time believed that the APU would auto shut down if it overheated; and that the primary concern was flying with 1 generator; which considering the perfect weather; I did not deem hazardous.Although I considered the nose wheel steering issue to be irrelevant; I considered it to be a personal preference of the Captain. It was on that I did not share; but I at the time; did not see that it mattered either way. I considered the choice between the two airports to be rather grey; and despite my preference for ZZZ; did not push further. I am filing this report because I have since changed my mind. Following some post flight research; I now believe that ZZZ was DEFINITELY and without doubt the nearest suitable airport because:The APU only auto shuts down when on the ground. When in flight; the APU will continue to run indefinitely. The concern with a APU OIL TEMP message is INDEED a overheating APU which will eventually lead to fire.With point 1 in mind; an emergency decent is at least plausible; and could have soon been mandatory.With further retrospection; the nose wheel steering/runway length idea was irrelevant and nonsensical.Considering all of the above; the decent angle between the two airports is irrelevant. Now that I see the obvious better decision; I think I should have refused to continue to destination. I still acknowledge that there is some room for debate; but this is my opinion at this time.




Synopsis: CL65 First Officer describes a generator failure in cruise and the use of the APU generator to take its' place. During descent an APU oil temperature EICAS message is received and the QRH states 'land at nearest suitable airport.' The Captain believes that since the aircraft is already descending the destination airport is the best choice and the First Officer disagrees believing that an airport directly below (aircraft at FL280) is the nearest suitable.