Airplane Oil-Cooler Fracture

On-going inspection and monitoring of the performance of an RV-10, a single-engine Amateur-built experimental airplane, to ensure safe and reliable operation was pursued. During routine inspections of the engine compartment, an unexplained oil leak was identified. Such oil leaks from Lycoming engines such as used in the airplane are not uncommon. Given the modest amount of oil observed, a watchful waiting approach was pursued.

Progression in the amount of leaking oil warranted more in-depth inspection. A progressing crack in the oil-cooler was found to be the source of the leak. The crack was identified before growing to the point of catastrophic rupture with risk of consequent engine compartment fire.

Trouble shooting methods used, fracture analysis of the crack, and root cause determination for the crack will be presented.