Experimental homebuilt with pusher propeller had a small portion of exhaust system break off and it ...

Attributes
ACN	343889
Time
Date	199608
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : oxv
State Reference	IA
Altitude	msl bound lower : 4500 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dsm
Operator	general aviation : personal
Make Model Name	Amateur (Home) Built
Operating Under FAR Part	Part 91
Flight Phase	cruise other other other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 20 flight time total : 1740 flight time type : 740
ASRS Report	343889
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	controller : provided flight assist flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Propeller failure, part of 1 blade of wooden propeller broke off caused by failure of exhaust system. About 6 inches of right exhaust pipe was missing. I think that exhaust pipe piece broke off, went through propeller arc, striking propeller causing a fracture which rapidly grew causing about 1/3 of 1 propeller blade to depart. We were in cruise flight en route GPS direct from cedar rapids to hutchinson at 4500 ft MSL. I was monitoring dsm approach since we would pass just south of their airspace. About 12 mi east of knoxville we experienced a vibration which quickly became very severe. I closed the throttles, moved mixture to idle cutoff and switched off magnetos. I pulled up to bleed off airspeed to get the propeller stopped. This happened at 58 KIAS. Established best glide and contacted dsm approach for vectors to nearest airport. They established radar contact and gave me a vector to knoxville airport. It became apparent we could not reach the airport so looked for possible sites and selected a portion of highway 92. Made a right pattern and landed about 10 mi east of knoxville. No damage to aircraft or ground vehicles or people. Removed aircraft to knoxville airport for repair.

Original NASA ASRS Text

Title: EXPERIMENTAL HOMEBUILT WITH PUSHER PROP HAD A SMALL PORTION OF EXHAUST SYS BREAK OFF AND IT PASSED THROUGH PROP, CAUSING PROP BLADE FAILURE.

Narrative: PROP FAILURE, PART OF 1 BLADE OF WOODEN PROP BROKE OFF CAUSED BY FAILURE OF EXHAUST SYS. ABOUT 6 INCHES OF R EXHAUST PIPE WAS MISSING. I THINK THAT EXHAUST PIPE PIECE BROKE OFF, WENT THROUGH PROP ARC, STRIKING PROP CAUSING A FRACTURE WHICH RAPIDLY GREW CAUSING ABOUT 1/3 OF 1 PROP BLADE TO DEPART. WE WERE IN CRUISE FLT ENRTE GPS DIRECT FROM CEDAR RAPIDS TO HUTCHINSON AT 4500 FT MSL. I WAS MONITORING DSM APCH SINCE WE WOULD PASS JUST S OF THEIR AIRSPACE. ABOUT 12 MI E OF KNOXVILLE WE EXPERIENCED A VIBRATION WHICH QUICKLY BECAME VERY SEVERE. I CLOSED THE THROTTLES, MOVED MIXTURE TO IDLE CUTOFF AND SWITCHED OFF MAGNETOS. I PULLED UP TO BLEED OFF AIRSPD TO GET THE PROP STOPPED. THIS HAPPENED AT 58 KIAS. ESTABLISHED BEST GLIDE AND CONTACTED DSM APCH FOR VECTORS TO NEAREST ARPT. THEY ESTABLISHED RADAR CONTACT AND GAVE ME A VECTOR TO KNOXVILLE ARPT. IT BECAME APPARENT WE COULD NOT REACH THE ARPT SO LOOKED FOR POSSIBLE SITES AND SELECTED A PORTION OF HWY 92. MADE A R PATTERN AND LANDED ABOUT 10 MI E OF KNOXVILLE. NO DAMAGE TO ACFT OR GND VEHICLES OR PEOPLE. REMOVED ACFT TO KNOXVILLE ARPT FOR REPAIR.

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.

Experimental homebuilt with pusher propeller had a small portion of exhaust system break off and it passed through propeller, causing propeller blade failure.