A320
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 180; Flight Crew Total 13000; Flight Crew Type 2950
Aircraft Equipment Problem Less Severe
General Maintenance Action
Aircraft
While operating at FL260 we began to observe a significant increase in engine Number 1 N1 vibration. Specifically; engine Number 1 N1 vibration was indicating approximately 3.3 and rising; while engine Number 2 N1 vibration was indicating approximately 0.2. We were in cruise flight at FL260; in icing conditions; with engine Number 1 [and] Number 2 anti-ice selected ON. The engine Number 1 N1 vibration indication continued to rise steadily to 5.0 and above and we could physically sense abnormal vibration on the left side of the aircraft. As this occurred; we initiated QRH 'Eng - High Vibration'. As we executed 'Eng - High Vibration'; we experienced a decrease in engine Number 1 N1 vibration to an approximate value of 0 when engine Number 1 thrust was reduced to; or near; idle. However; once thrust was increased to cruise; engine Number 1 N1 vibration increased and was eventually sustained at approximately 9.4. In accordance with the continuance of 'Eng - High Vibration'; we increased engine Number 1 thrust to 90% N1. No change in engine Number 1 N1 vibration occurred. The engine Number 1 N1 vibration value continued to be sustained at approximately 9.4. As the aforementioned occurred; we requested and received clearance to climb to FL320; in an effort to exit icing conditions. Once level at FL320; we were; in fact; clear of icing conditions.Upon completing 'Eng - High Vibration' QRH with no reduction in engine Number 1 N1 vibration at cruise thrust setting; we continued flight with engine Number 1 thrust at; or near; idle. We advised Dispatch of our [issue]. At this point; we were in range of [destination] (approximately twenty minutes from landing) and had begun the descent and arrival phase of the flight. We attempted to establish communication with [Maintenance] via Dispatch. However; as we descended; we lost radio communication with Dispatch. I provided a briefing to our Purser Flight Attendant. We continued our approach and arrival. We landed without incident; taxied to gate; and concluded the flight.
A320 Captain reported high vibration in Number 1 engine that led to operating the engine at or near idle for the latter part of the flight.