Mooney M-20

A welded steel-tube frame carries the loads, with aluminium (and some fibreglass) skins over it. The first M20 and M20A (1955 to 1960) had wooden wings and tails; all later ones are metal. The design is held under 1 type certificate (2A3, held by Mooney International Corporation). The FAA has issued 66 airworthiness directives (orders that owners must comply with) that name this model, most of them about engine. Operators and repair shops have filed 627 failure reports with the FAA since 1995, 48 of them in the last ten years: about 0.1 a year for every 100 aircraft on the register; the system most often named is engine. 495 approved modifications exist for it, the most by S-Tec Corporation.

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.