Date: 201310
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Aircraft component: AC Generator/Alternator
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Time Pressure; Communication Breakdown; Confusion; Distraction; Workload; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Procedure; MEL; Logbook Entry; Human Factors
Primary problem: Human Factors

Narrative: A CRJ-200 aircraft in ZZZ displayed an 'IDG 2' Caution message as the flight crew advanced power for takeoff. The crew aborted their takeoff at 50-60 KTS; and then returned to the gate. I asked the Captain if the IDG had been disconnected; to which he replied that it 'had not' been disconnected. I contacted Contract Maintenance in ZZZ to comply with the Maintenance Action and defer the Number 2 Generator. The Contract Mechanic complied with the Maintenance Action for the deferral for the Number 2 Generator and it was deferred per MEL 24-11-1b. The aircraft then departed ZZZ enroute to ZZZ1.Some time after the CRJ-200 had departed ZZZ; I was reviewing work that I had performed in the earlier hours of my shift on various aircraft.  As I read through the deferral for the IDG on the CRJ-200; I came to the conclusion that the EICAS Caution message 'IDG 2' is caused by a low oil pressure or high oil temperature condition; and should be manually disconnected and deferred per MEL 24-11-1a; regardless of whether or not the IDG had been disconnected by the [flight] crew.  After getting a brief description of the discrepancy with the Captain; I asked him if the IDG had been disconnected; to which he replied that it had not been disconnected.  I then reviewed the deferrals for the IDG Constant Speed Drive (CSD) (24-11-1a); and for the IDG Generator (24-11-1b). The remarks section of MEL 24-11-1a deferral states that 'the respective IDG is disconnected;' whereas MEL 24-11-1b states that the 'respective Gen 1/2 switch is selected to the 'Off' position' (and is not disconnected). Because the IDG had not been previously disconnected; I decided to use MEL (24-11-1b). I had the Contract Mechanic check oil level in the opposite IDG and APU and comply with the Maintenance Action for that deferral. Upon realizing that the incorrect MEL may have been applied to the aircraft; I contacted ZZZ1 Line Maintenance to have them defer the Number 2 IDG Constant Speed Drive per MEL 24-11-1a and physically disconnect the IDG.This event has been a reminder for me personally to be sure I review the messages displayed on EICAS and verify that the correct MEL is used as a Corrective Action. Perhaps a memo to all maintenance controllers specifically about this deferral would be helpful. High workload. Flight delay. Dayshift.




Synopsis: A Maintenance Controller explains why he revised a previous MEL deferral he had applied to a CRJ-200 aircraft that had aborted takeoff due to an EICAS 'IDG 2' Caution message.  After later reviewing probable causes for the EICAS message; he decided MEL 24-11-1A was more appropriate; but required a physical disconnection of the IDG Constant Speed Drive (CSD).