Narrative:

During engine start we received an amber idg 2 cas message while starting the left engine; the right engine had already been started. I contacted maintenance control and we agreed to defer the right idg and run the APU continuously for the flight. We had plenty of fuel since we only had two passengers and this was a tanker leg; so dispatch agreed and sent the MEL addition via ACARS. After finishing the write-up and deferral the maintenance controller walked me through the M/fc [(maintenance by flight crew)] functions and we then left the gate. A short while after reaching our planned cruise altitude we then received an amber APU oil press caution message. We referenced the QRH and it instructed us to land at the nearest suitable airport if the APU was essential for flight; which in this case it was.I elected to divert to a nearby regular airport and notified ATC. The first officer obtained the new clearance and proceeded towards the new destination while I notified the flight attendant; passengers; dispatch via ACARS; and company operations at our diversion airport and requested a gpu at our gate. The balance of the flight was uneventful. Upon landing we were expecting the APU to auto-shutdown after 60 seconds but it continued to run. Once ground power was established I shutdown both engines and the APU.maintenance arrived shortly thereafter and quickly found the problem of low oil in the APU as well as in the right idg. They repaired both and cleared the MEL. I contacted dispatch and informed them that we still had 5;000 pounds of fuel on board and wanted to check if that was enough to go to continue the flight or if we would need to be re-fueled. They determined that we would have enough fuel so we obtained a new release and flight plan and then continued to destination without incident.

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Original NASA ASRS Text

Title: With a right IDG defered prior to departure; a CRJ crew intended to run the APU for electrical power redundancy. When they received an APU OIL PRESS warning enroute they diverted for maintenance attention. After servicing the oil quantity in both systems they departed to their original destination.

Narrative: During engine start we received an amber IDG 2 CAS message while starting the left engine; the right engine had already been started. I contacted Maintenance Control and we agreed to defer the right IDG and run the APU continuously for the flight. We had plenty of fuel since we only had two passengers and this was a tanker leg; so Dispatch agreed and sent the MEL addition via ACARS. After finishing the write-up and deferral the Maintenance Controller walked me through the M/FC [(Maintenance by Flight Crew)] functions and we then left the gate. A short while after reaching our planned cruise altitude we then received an amber APU OIL PRESS caution message. We referenced the QRH and it instructed us to land at the nearest suitable airport if the APU was essential for flight; which in this case it was.I elected to divert to a nearby regular airport and notified ATC. The First Officer obtained the new clearance and proceeded towards the new destination while I notified the Flight Attendant; passengers; Dispatch via ACARS; and company operations at our diversion airport and requested a GPU at our gate. The balance of the flight was uneventful. Upon landing we were expecting the APU to auto-shutdown after 60 seconds but it continued to run. Once ground power was established I shutdown both engines and the APU.Maintenance arrived shortly thereafter and quickly found the problem of low oil in the APU as well as in the right IDG. They repaired both and cleared the MEL. I contacted Dispatch and informed them that we still had 5;000 pounds of fuel on board and wanted to check if that was enough to go to continue the flight or if we would need to be re-fueled. They determined that we would have enough fuel so we obtained a new release and flight plan and then continued to destination without incident.

Data retrieved from NASA's ASRS site as of July 2013 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.