Regional Jet 700 ER/LR (CRJ700)
Dispatch Dispatcher
Situational Awareness; Communication Breakdown; Training / Qualification
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural MEL / CDL
General None Reported / Taken
Human Factors; Aircraft; MEL
Maintenance deferred the IDG [Integrated Drive Generator] on the aircraft. There was a previous MEL that stated operations could not be dependant on the APU. Looking over the MEL's at the time of deferral I discussed it with the PIC and we did not realize both MEL's would render the plane unairworthy. We amended the release with the IDG deferral and the flight departed. Maintenance did not call to advise us of the deferral of the IDG or discuss the issues having both MEL's on the aircraft at the same time. Looking over the previous MEL it was not clear to me that the APU could not be depended on for operations. The Captain also did not realize that plane should not depart with the deferrals.We need better communication between Maintenance and Dispatch regarding airworthiness. I need to understand clearly what the MEL's are indicating and the performance issues that will arise when more than one deferral is on the aircraft. The MEL should be clearer with possible notes indicating that the IDG's must be operative.
When neither the Dispatcher nor the Captain noted the MELed IDG; combined with a previously noted APU MEL declaring it unable to provide electrical system redundancy; the flight was released with only a single source of electrical AC power.