Pretty sure the horse is not dead so a couple more kicks. Let's define Airworthy Found this one.
"ANSWER: There are two conditions that must be met for an aircraft to be considered "Airworthy”
1. The aircraft must conform to its type design (TC). Conformity to type design is considered attained when the aircraft configuration and the components installed are consistent with the drawings, specifications, and other data that are part of the TC, which includes any supplemental type certificate (STC) or other approved alterations.
2. The aircraft must be in a condition for safe operation. This refers to the condition of the aircraft relative to wear and deterioration, for example, skin corrosion, window de-lamination or crazing, fluid leaks, tire wear, etc.
If either of these two conditions cannot be met, the aircraft is considered to be un-airworthy.
So, the goal for those persons who operate and maintain aircraft is to keep them in an airworthy condition or what is referred to as “continued airworthiness”. "
If you took a large sample of late 1900s airplanes and reviewed them against the Type Design I bet that about 50% would not pass.