SR22
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 16; Flight Crew Total 648; Flight Crew Type 458
Situational Awareness
Aircraft Equipment Problem Less Severe
Air Traffic Control Issued New Clearance; Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
I left on an IFR flight plan. I did my normal/full preflight inspection and completed all checklists. The Takeoff and climb were normal. I was at about 8;500 ft just coming up on my cruise altitude of 9;000 ft when I noticed a vibration/shaking that I had never experienced before. As my speed came up at 9;000 ft; the vibration/shaking increased. I looked at engine instruments and all were normal/nominal. I looked at the wings and tail and nothing unusual was apparent. The vibration seemed to be getting worse.  I was being handed off by Departure but I told the controller I was having an issue with the plane and needed to divert and land immediately. I requested ZZZ; she said - I think - that ZZZ was below minimums and suggested ZZZ1 which was at 700 ft. I took that. I was asked if I was declaring an emergency; I believe I said something like 'not now'; but on the turn back and descent to ZZZ1; the vibration seemed to get worse so I [advised ATC]. I decreased power to approach levels (about 35% power) and descended pretty quickly from 9;000 to 3;000. Once at 3;000 ft and at much lower speeds (about 120 kts) the vibration lessened. I received vectors to the ILS; came out of the clouds at about 800 ft; no issues on the approach or landing. Tower was very helpful; asked details for her report; and contacted a mechanic on field. Once out of the plane; I did a walk around and found the issue: an aerodynamic fiberglass faring at the top of the passenger side landing gear strut had come loose and was dangling about 6 inches below where it should be and would have been disrupting airflow under that wing. After consulting with a Cirrus mechanic; I had the faring and wheel pants removed from the landing gear. I did a flight test in the pattern and the plane handled normally. I then flew to where a Cirrus mechanic is located for inspection and eventual repairs.
SR22 pilot experiences an abnormal vibration as he climbs to 9000 feet on an IFR flight plan. When the cause cannot be determined the reporter elects to divert to a suitable airport and lands safely. Post flight reveals that a gear strut fairing at the fuselage is partially detached and the likely cause of the vibration.