Narrative:

Approximately 30 NM east of milwaukee, I experienced a sudden small vibration while cruising at 6000 ft en route to mwc. I troubleshooted and finding no problems with the engine, slowed to reduce the vibration. Approach was informed that I was experiencing this problem and we continued to our destination. We were being vectored for the VOR runway 4 at mwc when approximately 5 NM south of the airport, I lost 5 inches of manifold pressure on the right engine. The engine began to vibrate and backfire violently. I requested a vector direct the field as I was VMC and was cleared for the visual and handed off to mwc tower. I again troubleshooted and found no problems. I then shut down and secured the right engine, informed tower we were actual single engine and landed uneventfully. The right engine seemed to be capable of producing power, but I decided to shut down because of the vibration, backfiring and I didn't want to have to deal with any larger problems on the visual approach near the ground. Once the engine was feathered, all vibration stopped. I had received 1 hour of dual on single engine procedures 5 days earlier. This greatly helped things go smoothly. Callback conversation with reporter revealed the following information: the reporter stated he was flying a beech duchess BE66. He said he would not do anything differently other than have declared an emergency so that everyone would be aware he was on a single engine and at some point on final committed to land. He stated he has practiced single engine gars but there is not much climb performance with an engine out.

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Original NASA ASRS Text

Title: THE RPTR EXPERIENCED A VIBRATION IN HIS R ENG WHICH SUBSEQUENTLY, ABOUT 5 MI FROM THE ARPT, DETERIORATED TO A 5 INCH DROP IN MANIFOLD PRESSURE AND ENG BACKFIRING. THE RPTR ELECTED TO SHUT THE ENG DOWN AND LAND ON ONE ENG.

Narrative: APPROX 30 NM E OF MILWAUKEE, I EXPERIENCED A SUDDEN SMALL VIBRATION WHILE CRUISING AT 6000 FT ENRTE TO MWC. I TROUBLESHOOTED AND FINDING NO PROBS WITH THE ENG, SLOWED TO REDUCE THE VIBRATION. APCH WAS INFORMED THAT I WAS EXPERIENCING THIS PROB AND WE CONTINUED TO OUR DEST. WE WERE BEING VECTORED FOR THE VOR RWY 4 AT MWC WHEN APPROX 5 NM S OF THE ARPT, I LOST 5 INCHES OF MANIFOLD PRESSURE ON THE R ENG. THE ENG BEGAN TO VIBRATE AND BACKFIRE VIOLENTLY. I REQUESTED A VECTOR DIRECT THE FIELD AS I WAS VMC AND WAS CLRED FOR THE VISUAL AND HANDED OFF TO MWC TWR. I AGAIN TROUBLESHOOTED AND FOUND NO PROBS. I THEN SHUT DOWN AND SECURED THE R ENG, INFORMED TWR WE WERE ACTUAL SINGLE ENG AND LANDED UNEVENTFULLY. THE R ENG SEEMED TO BE CAPABLE OF PRODUCING PWR, BUT I DECIDED TO SHUT DOWN BECAUSE OF THE VIBRATION, BACKFIRING AND I DIDN'T WANT TO HAVE TO DEAL WITH ANY LARGER PROBS ON THE VISUAL APCH NEAR THE GND. ONCE THE ENG WAS FEATHERED, ALL VIBRATION STOPPED. I HAD RECEIVED 1 HR OF DUAL ON SINGLE ENG PROCS 5 DAYS EARLIER. THIS GREATLY HELPED THINGS GO SMOOTHLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE WAS FLYING A BEECH DUCHESS BE66. HE SAID HE WOULD NOT DO ANYTHING DIFFERENTLY OTHER THAN HAVE DECLARED AN EMER SO THAT EVERYONE WOULD BE AWARE HE WAS ON A SINGLE ENG AND AT SOME POINT ON FINAL COMMITTED TO LAND. HE STATED HE HAS PRACTICED SINGLE ENG GARS BUT THERE IS NOT MUCH CLB PERFORMANCE WITH AN ENG OUT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.