Hughes 269 300 series helicopters

A welded steel-tube frame carries the loads, with aluminium (and some fibreglass) skins over it. An open steel-tube frame. The design is held under 1 type certificate (4H12, held by Schweizer Rsg LLC). The FAA has issued 54 airworthiness directives (orders that owners must comply with) that name this model, most of them about rotorcraft systems. Operators and repair shops have filed 214 failure reports with the FAA since 1995, 1 of them in the last ten years: about 0.5 a year for every 100 aircraft on the register; the system most often named is engine. 64 approved modifications exist for it, the most by Electronics International.

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.