Flight Crew Private
Flight Crew Last 90 Days 6; Flight Crew Total 1272; Flight Crew Type 1272
Workload; Time Pressure; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Less Severe; Airspace Violation All Types
Flight Crew Diverted; Flight Crew Exited Penetrated Airspace; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
Cruising at 6;500 feet experienced a sudden onset of engine roughness and corresponding reduction of power. EGT of Number 4 cylinder was negligible. Not knowing the seriousness of the problem; I began evaluating off field landing sights as I trimmed for best glide speed in anticipation of a full engine out situation. I had the sectional in my lap and saw a paved airport nearby; did some mental estimates on speed; rate of descent and concluded it was makeable. I turned towards the airport; selected the CTAF and requested and received active runway so I could plan the direct approach.Next I tried combinations of throttle; RPM and mixture with no success in smoothing out the vibrations. Still able to maintain some power; my attention turned to informing the traffic on CTAF (there's an active flight school there and the pattern was quite busy) that I was inbound with one cylinder out and would be making an expedited landing.Through all this; aviate/navigate/communicate; I did not feel; since the engine had been producing some power; that this constituted an emergency; but I was very anxious that one could develop rapidly depending on whatever was wrong. I elected not to squawk 7700; nor did I feel I wanted to divert attention to changing frequency to Approach and go through the story. I was focused on getting on the ground ASAP.With the runway aligned perpendicular to my flight path and blocked by trees; I spend a lot of time trying to find it. During one glance at the GPS (Garmin 430) I noticed I was probably right on the boundary of the Delta airspace and had descended to 2;000 feet; but moving away from it. I had observed no other aircraft in my vicinity.The landing was uneventful; and subsequent inspection discovered a completely severed exhaust pipe on Number 4.The workload and the anxiety of losing complete power contributed to a possible brief violation of Delta Airspace without contacting ATC.
A VANS RV pilot reported that he detected what he thought was a failed engine cylinder and diverted to a nearby airport. On the ground; he determined the Number 4 cylinder exhaust pipe had severed completely.