Skyhawk 172/Cutlass 172
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 30; Flight Crew Total 210; Flight Crew Type 57
Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Critical; Inflight Event / Encounter Other / Unknown
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Declared Emergency
Aircraft
While at cruise I heard a loud noise and then felt a massive shuddering of the aircraft. Both hands were used for control of the yoke. I declared an emergency with ATC; [and] then pulled the power back to idle. The oil access door came open and shortly afterwards the dip stick came flying out. ATC vectored us for a landing at an airport which was 3NM away from our present position. Upon reaching the airport environment; we flew a left hand circle around the approach end of runway while descending. Upon turning final; with landing assured; I pulled the mixture to full lean; and turned off the magnetos and fuel tanks. We landed on runway and rolled onto a taxiway. At that time we noticed that several inches of prop were missing from one end. There was no evidence of blood or feathers.
When; while at cruise; the unexplained loss of several inches of one prop blade resulted in uncontrollable vibration of the C172-R the pilot was vectored to a nearby airport where he landed safely. There was no visible evidence of a bird strike.