On April 28, 2000, the FAA issued priority letter AD 2000-08-51 mandating material inspections on Teledyne-Continental Motors (TCM) crankshafts manufactured from April 1998- March 2000. ï¿½ The AD mandates the inspection procedure recommended in TCM mandatory service bulletin MSB-00-5A. ï¿½ TCMï¿½s recommended inspection procedure involves drilling two small core samples from the crankshaft propeller flange to be sent to TCM for metallurgical inspection. ï¿½ If defects are found in the samples, the crankshaft must be replaced.
TCM cited composition and processing deficiencies during their supplierï¿½s steel production process as the cause of 11 recent crankshaft failures. ï¿½ In the AD, the FAA clarifies that investigators originally believed the suspect steel to be within specifications and therefore free of defect. ï¿½ Later though, through the development of more stringent testing procedures, investigators learned that anomalies in the trace-element composition and material processing of the steel combined to create the unsafe condition. ï¿½ To ensure the continued safe operation of aircraft utilizing engines equipped with a suspect crankshaft TCM is recommending the inspection of nearly 2,200 crankshafts.
ï¿½ TCM has identified 11 fractures in the connecting rod journals on straight drive engines manufactured in 1998 and 1999.
ï¿½ The cause of the fractures has been identified as unique material composition characteristics combined with process control variations that occurred during the material melt process. ï¿½ Specification material evaluation techniques were inadequate to detect these anomalies, and therefore the defects were not revealed during manufacture.
ï¿½ The FAA indicates that specification material evaluation techniques have been improved to preclude a reoccurrence of this condition.
ï¿½ Fractures have occurred in new, rebuilt, and field overhauled engines with operational times varying from 15 to 1257 hours.
ï¿½ Affected engines include: IO-360, TSIO-360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, TSIOL-550 series new and rebuilt direct drive engines assembled utilizing a crankshaft that was manufactured from April 1, 1998 through March 31, 2000.
ï¿½ Engine and crankshaft serial numbers of affected engines are listed in TCMï¿½s mandatory service bulletin MSB-00-5C, dated October 10, 2000.
ï¿½ TCMï¿½s recommended inspection procedure involves, within the next 10 hours TIS, drilling two small core samples from the crankshaft propeller flange to be sent to TCM for metallurgical inspection.
ï¿½ TCM will supply the equipment necessary to drill the two core samples and has vowed to provide the results of the metallurgical testing to affected aircraft owners within 48 hours after receipt of the samples.
ï¿½ Sources at TCM indicate that the manufacturer will cover the parts and labor costs of the initial inspection and any necessary parts replacements in accordance with their warranty.
ï¿½ FAA has issued revised AD-2000-23-21 (superseded priority letter AD 2000-08-51) mandating the TCM recommended inspection and repairs.
ï¿½ To determine if your engine is affected, check the crankshaft serial number and check MSB-00-5C, visit the TCM website at http://www.tcml ink.com and/or call TCMï¿½s customer service department at 1-888-200-7565.
AOPA agrees that, in this particular situation, the potential for in-flight catastrophic engine failure warrants airworthiness action. ï¿½ AOPA will continue to closely monitor the activities of TCM and the FAA and take actions as necessary to ensure fair and reasonable treatment of our members.
ï¿½ On October 10, 2000 TCM issued MSB-00-5C, adding an additional 388 cranshafts to the list of affected engines.
ï¿½ On May 25, 2000 issued MSB-00-5B expanding the applicability of the crankshaft material inspections to include nearly 2,200 crankshafts.
ï¿½ On April 28, 2000, TCM issued revised Mandatory Service Bulletin MSB-00-5A
ï¿½ On April 28, 2000, FAA issued priority letter AD 2000-08-51
ï¿½ On April 14, 2000, TCM issued Mandatory Service Bulletin MSB-00-5
ï¿½ On November 27, 2000, the FAA issued AD-2000-23-21
Priority Letter AD-2000-08-51, April 28, 2000