CYLINDER CRACKS - OR ARE THEY?

Ken was having issues with the fuel boost pump on his Cessna 180, so he sent his airplane to the Aircraft Maintenance Organisation (AMO) to have his mechanic investigate it. A few days later, the AMO called with some unpleasant news unrelated to the fue

The AMO advised Ken that two of the six cylinders on his Continental IO-470 appeared to have cracked heads, with cracks running between the fuel nozzle and the top spark plug. The mechanic said that such head cracks were not repairable and so both cylinders would need to be replaced. Estimated cost of parts and labour was $6,000. Crumbs!

Ken was a SavvyQA maintenance consulting subscriber, so he contacted Savvy for advice. Savvy’s account manager Tony Barrell explained that the location described was indeed a common location for cracks to develop in Continental cylinder heads. On the other hand, Tony told Ken that in Savvy’s experience more than half of the reported cracks in this area turned out not to be cracks at all, but rather superficial cosmetic flaws in the head casting. In fact, unless the crack is clearly blue-stained and leaking fuel, it rarely turns out to be an actual crack. Therefore, Tony suggested that Ken ask the AMO to sand the suspected crack area smooth and then perform a dye penetrant inspection (DPI) of the area.

Any cracks will show up clearly as a red line on the white surface as red-dyed penetrant embedded in the cracks is wiped out of the crack and absorbed by the white powdery developer. Ken went to the AMO and watched whilst his mechanic performed the DPI procedure. The test showed clearly that there was not a crack in either cylinder head. Ken’s mechanic was satisfied; the two cylinders remained in service and Ken found a better use for his $6,000.

Ken’s decision to get a second opinion from Savvy was a smart move that saved him more than $6,000 in unnecessary maintenance expense, plus a week or two of downtime and the risky business of cylinder replacement in the field. Ken’s SavvyQA subscription costs $375 / year for piston singles like the Cessna 180 and entitles him to unlimited consultations throughout the year. This one second opinion saved him enough to pay for the service for the next 16 years. This is not unusual. We almost always save our clients more in reduced maintenance costs than the annual subscription cost. Often a LOT more. Wouldn’t you benefit by having Savvy watching your six-cylinder engine?

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