|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 0|
|Operator||general aviation : instructional|
|Make Model Name||SR20|
|Operating Under FAR Part||Part 91|
|Function||oversight : supervisor|
|Qualification||technician : airframe|
technician : powerplant
|Experience||maintenance technician : 1|
|Function||maintenance : technician|
|Anomaly||aircraft equipment problem : critical|
other anomaly other
|Independent Detector||other other : 2|
|Resolutory Action||none taken : detected after the fact|
|Problem Areas||Flight Crew Human Performance|
An SR20 aircraft in our fleet was squawked with an oil leak. Upon pressurizing the case; a crack was found in the vicinity of the front alternator #1 mount and the propeller thrust bearing. Two months later; another SR20 was squawked with an oil leak and a crack was found in the same location. Each aircraft has experienced a propeller strike; one light and one more severe. Each of the engines were repaired; yellow tagged; and reinstalled for service. The engines are tcm io-360-ES6 with serial numbers just 4 apart. This engine is unique to the SR20 with the forward alternator #1 placement. We have heard of other similar incidents from the engine overhaul shop and also cirrus; and are working closely with the aircraft company and also the engine manufacturer. One engine is 757 hours tt since new; 305 hours since overhaul following a propeller strike. The other 875 tt since new; 132 hours since overhaul following propeller tip strike. Each case was certified as serviceable by a repair shop following the propeller strikes. We realize the history of these engines; but feel the cracking is due to a design flaw or possibly a bad batch of cases. We've been in contact directly with continental motors; with full disclosure of the aircraft's histories and they've agreed to supply 2 new cases. After further query through cirrus; tcm has agreed to completely rebuild one of the engines free of charge. We do not know for sure; but we suspect a design flaw in the crankcase of these io-360-ES6 engines. We continue to monitor our remaining fleet cirrus SR20 engines for signs of cracking every 25 hours.callback conversation with reporter revealed the following information: the reporter stated the engines are tcm io-360-ES6 and are unique to the SR20 with the forward alternator #1 placement. The engines have been shipped off to the manufacturer and the cases will be replaced. The reporter indicated some contacts in the industry report the crack can be repaired by welding but does not correct a design fault.
Original NASA ASRS Text
Title: A CIRRUS SR20 OPERATOR RPTS TWO ENG CASE CRACKS AT THE FRONT ALTERNATOR #1 MOUNT AND PROP THRUST BEARING. FOUND BY OIL LEAKAGE.
Narrative: AN SR20 ACFT IN OUR FLEET WAS SQUAWKED WITH AN OIL LEAK. UPON PRESSURIZING THE CASE; A CRACK WAS FOUND IN THE VICINITY OF THE FRONT ALTERNATOR #1 MOUNT AND THE PROP THRUST BEARING. TWO MONTHS LATER; ANOTHER SR20 WAS SQUAWKED WITH AN OIL LEAK AND A CRACK WAS FOUND IN THE SAME LOCATION. EACH ACFT HAS EXPERIENCED A PROP STRIKE; ONE LIGHT AND ONE MORE SEVERE. EACH OF THE ENGS WERE REPAIRED; YELLOW TAGGED; AND REINSTALLED FOR SVC. THE ENGS ARE TCM IO-360-ES6 WITH SERIAL NUMBERS JUST 4 APART. THIS ENG IS UNIQUE TO THE SR20 WITH THE FORWARD ALTERNATOR #1 PLACEMENT. WE HAVE HEARD OF OTHER SIMILAR INCIDENTS FROM THE ENG OVERHAUL SHOP AND ALSO CIRRUS; AND ARE WORKING CLOSELY WITH THE ACFT COMPANY AND ALSO THE ENG MANUFACTURER. ONE ENG IS 757 HOURS TT SINCE NEW; 305 HOURS SINCE OVERHAUL FOLLOWING A PROP STRIKE. THE OTHER 875 TT SINCE NEW; 132 HOURS SINCE OVERHAUL FOLLOWING PROP TIP STRIKE. EACH CASE WAS CERTIFIED AS SERVICEABLE BY A REPAIR SHOP FOLLOWING THE PROP STRIKES. WE REALIZE THE HISTORY OF THESE ENGS; BUT FEEL THE CRACKING IS DUE TO A DESIGN FLAW OR POSSIBLY A BAD BATCH OF CASES. WE'VE BEEN IN CONTACT DIRECTLY WITH CONTINENTAL MOTORS; WITH FULL DISCLOSURE OF THE ACFT'S HISTORIES AND THEY'VE AGREED TO SUPPLY 2 NEW CASES. AFTER FURTHER QUERY THROUGH CIRRUS; TCM HAS AGREED TO COMPLETELY REBUILD ONE OF THE ENGS FREE OF CHARGE. WE DO NOT KNOW FOR SURE; BUT WE SUSPECT A DESIGN FLAW IN THE CRANKCASE OF THESE IO-360-ES6 ENGS. WE CONTINUE TO MONITOR OUR REMAINING FLEET CIRRUS SR20 ENGS FOR SIGNS OF CRACKING EVERY 25 HOURS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ENGS ARE TCM IO-360-ES6 AND ARE UNIQUE TO THE SR20 WITH THE FORWARD ALTERNATOR #1 PLACEMENT. THE ENGS HAVE BEEN SHIPPED OFF TO THE MANUFACTURER AND THE CASES WILL BE REPLACED. THE RPTR INDICATED SOME CONTACTS IN THE INDUSTRY RPT THE CRACK CAN BE REPAIRED BY WELDING BUT DOES NOT CORRECT A DESIGN FAULT.
Data retrieved from NASA's ASRS site as of January 2009 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.