Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Became Reoriented
Aircraft
We experienced a high fan vibration (1.8 mils) on the left engine during climb to FL280.  Climbing through FL230 were cleared to climb to FL360; which was our filed cruise altitude.  Since we were heavy (>72;000 Lbs.) and it was warm (ISA+13C); I checked the altitude capability chart to ensure we had the thrust to climb to FL360.  While I was looking at the chart; the First Officer noticed the fan vibrations on the left engine; and pointed it out to me.  At that point it was still in the green (1.6 mils); but increasing.  When it hit 1.7 mils; I told the First Officer to get the QRH; and read the N1 Fan Vibration procedure.  As he was reading the procedure; the engine exceeded 1.7 and reached 1.8 mils; the first step into the yellow range.  Since we were approaching FL280; in compliance with the QRH procedure; I reduced the thrust on the engine and with ATC's concurrence; we leveled off at FL280.  The left engine vibration indication remained about 1.6 to 1.7 mils and we decelerated to Mach 0.70; which kept the left engine vibration indication at about 1.6 mils.  Since we had the vibration under control; the ITT; oil pressure; and oil temperature were all within normal limits; and heard; more than felt; the fan vibration; I opted NOT to shut down the engine; and to continue to destination.  Using ACARS; I contacted my Dispatcher; relayed the situation; and obtained the fuel burn and time for our aircraft weight; fuel on board; and Mach 0.70 cruise at FL280.  Since we had sufficient fuel on board for the reduced cruise altitude; and Mach; I chose to continue where we landed; and proceeded to the gate uneventfully.
CRJ-700 Captain experiences fan vibration climbing to FL360 and elects to stop at FL280 and reduce thrust until vibration is below the caution range. Flight continues to destination and lands uneventfully.