Bellanca 17 Viking

A welded steel-tube fuselage and wooden wings, all covered in fabric: the construction of the 1930s and 1940s, which makes wood rot and fabric age the inspection items. The Viking's wings are wood, which is why its inspections matter. The design is held under 2 type certificates. The FAA has issued 18 airworthiness directives (orders that owners must comply with) that name this model, most of them about engine. Operators and repair shops have filed 44 failure reports with the FAA since 1995, 7 of them in the last ten years: about 0.2 a year for every 100 aircraft on the register; the system most often named is engine. 208 approved modifications exist for it, the most by Century Flight Systems INC.

Sources: the FAA's type certificate data sheets, airworthiness directives, supplemental type certificates, special conditions and special airworthiness information bulletins (Dynamic Regulatory System), and the FAA's service difficulty reports. A failure report is what an operator or repair station chose to file; the counts show reporting as much as reliability, and larger and commercial fleets report more. How the systems are grouped.