Reciprocating-engine powered low-capacity transport aircraft (8 to 10 passengers) provide an important public transport connection throughout regional Australia. In the period January 2000 to December 2005, twenty powertrain structural failures of high-power (300 to 375 brake horsepower) horizontally-opposed, reciprocating engines were associated with air safety occurrences reported to the ATSB. These occurrences ranged in severity from; in-flight engine shutdown; engine failure and forced landing; engine failure combined with in-flight fire and fracture of both upper engine mounts; to the…