Date: 201308
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: A330
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Engine Control
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Inspector; Quality Assurance / Audit
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Confusion; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft; Chart Or Publication; Procedure; Manuals; Company Policy
Primary problem: Ambiguous

Narrative: The flight crew called Maintenance Control and reported that they have a Number 1 engine that is slow to respond with associated ECAM message. At that time that I was conversing with the crew I was looking at the computer for the associated faults. The computer showed an 'ENG 1 CTL SYS FAULT.' I asked the crew if they also see this fault on ECAM. The crew responded that they do not see this fault and only have 'ENG1 slow to respond.' Crew also relayed that there are no ECAM actions with this fault. Crew also reported that they cannot achieve more then 1.2 EPR with autothrottles ON or OFF. At that time it was decided to have the aircraft return to the departure airport. Aircraft returned safely. According to the message associated with 'ENG 1 CTL SYS FAULT' it refers to the Fuel Metering Unit (FMU) as the faulty component and that the FMU needs to be replaced. Maintenance replaced the FMU and did the ground checks per the AMM and the FMU operated normally. Subsequently a Verification flight deferral was issued for the FMU replacement in accordance with Company A330 manual.According to our A330 documents after an in-flight engine shutdown; throttle back; un-commanded power change or surge or an inability to control an engine or obtain desired power PAX NOT AUTHORIZED for Verification flight. Looking at the log page associated with this event it states: 'ATB: ENG 1 CTL SYS FAULT' in Cruise [This is Not the fault that was relayed to me during the phone patch]. No where does it state that the crew did not obtain desired power from the number 1 engine. Verification flight for Number 1 engine FMU replacement was accomplished by the crew on a flight. The crew reported back to Maintenance Control 1 hour after departing and said the Number 1 engine FMU and engine operated normally and they are continuing on to the filed destination. Subsequently; the destination station maintenance cleared the Verification flight deferral.1. Even if the flight crew gives a verbal notification on their defect; the crew needs to be accurate on their defects in the aircraft log book so the correct actions can be taken. 2. Before issuing any Verification flight. All personnel needs to review the Company A330 documents to ensure all guide lines are followed.




Synopsis: An A330 ECAM alerted ENG 1 SLOW TO RESPOND in flight; but the Maintenance Control Computer displayed ENG 1 CTL SYS FAULT which indicated a Fuel Metering Unit fault so the aircraft returned to the departure station. Subsequently; no test flight was flown; but a revenue flight crew reported normal operation.