Date: 201205
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Autopilot
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Lead Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Situational Awareness; Confusion; Communication Breakdown; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft; Procedure; Manuals; MEL; Logbook Entry; Human Factors
Primary problem: Human Factors

Narrative: A B757-200 aircraft had an inbound write-up for the Autopilot System. An MEL 22-10-01C was applied; which has you pull and collar all three FCC SERVO Circuit Breakers (C/Bs). The next day; the aircraft was a Routine Overnight Maintenance in ZZZ1 and the Mode Control Panel (MCP) was replaced which cleared the MEL. The Lead; who was assigned the aircraft; accomplished the Operational Test of the panel and completed the CAT Check to re-certify the aircraft. The aircraft departed from ZZZ1 to ZZZ2 and while en route; the flight crew tried to engage the Center Autopilot; it would not work; nor would the Right or Left Autopilot. The flight crew found all three Flight Control Computer Servo C/Bs still collared.The aircraft departed ZZZ1 for ZZZ2; at 17;000 FT; the First Officer; who was flying the aircraft; wanted the Center Autopilot engaged; it wouldn't engage. The Captain tried the Left and then Right Autopilot but they would not engage either. The Captain checked the overhead C/B panel and found all three Flight Control Computer Servo C/Bs still collared. Unable to determine cause; the flight crew called Maintenance Control over the radio; found that ZZZ1 Maintenance replaced the Mode Control Panel (MCP); cleared the MEL; and that it was OK to take the [C/B] collar's off and reset the three C/B's. The Autopilot System returned to normal and the rest of the flight was un-eventful. No maintenance actions were required. I would also like to [recommend] one more comprehensive fix to prevent the recurrence of 'Not reactivating' an aircraft system after clearing an MEL. The Desk Supervisor receives an hourly report from the Leads on what MELs were cleared and which ones will remain. I would like for him to verify; when an MEL is removed to: First; check to see if when the MEL was applied; or was a special procedure accomplished and second; confirm with the Lead / mechanics; if required; that the system is re-activated (C/Bs pushed back in; valves re-opened; placards removed from cockpit /logbook).




Synopsis: A Lead Mechanic reports a deferred Autopilot System had been cleared after a Mode Control Panel (MCP) had been replaced on a B757-200 aircraft. However; after departure; the flight crew notified Maintenance Control the Left; Center and Right autopilots would not engaged. All three Flight Control Computers (FCCs) Circuit Breakers (C/Bs) were still collared.