Airworthiness
In the U.S., Title 14, Code of Federal Regulations, Subchapter F, Part 91.7 states: "a) No person may operate an aircraft unless it is in an airworthy condition.
The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur which compromise the airworthiness."
One airworthiness regulation is found in ICAO international standard of Annex 8 to Chicago Convention on International Civil Aviation which defines "airworthy" - in respect of an aircraft, engine, propeller or part there of - as "The status of an aircraft, engine, propeller or part when it conforms to its approved design and is in a condition for safe operation".
[3] The main objective of these rules are to establish and to maintain a high and uniform security level at the civil aviation in Europe.
In application, airworthiness standards include a probability of loss of aircraft (PLOA) that is designed to be controllable (PLOAdc) as an overall attribute.
[5] Setting a sufficiently robust PLOA factor for the aircraft's ability to safely attain, sustain, and terminate flight protects the souls on board.
For military unmanned aircraft, France developed an unmanned-unique airworthiness concept, later adapted by NATO, that isolates failures catastrophic to human life.
To be certified to fly over any population density, an hypothetical uncontrolled crash assumes that human life at the point of impact is lost.
While the aircraft may be lost, residual maneuverability directing to an unpopulated point of impact means this alternative is not catastrophic and therefore not an airworthiness factor.
1321/2014 controls the continuing of the airworthiness of aircraft and aeronautical products, components and equipment and the approval of the organizations and staff who involve in these tasks.
A more generic and non-process oriented definition of airworthiness is in JSP553 Military Airworthiness Regulations (2006) Edition 1 Change 5: The ability of an aircraft or other airborne equipment or system to operate without significant hazard to aircrew, ground crew, passengers (where relevant) or to the general public over which such airborne systems are flown This definition applies equally to civil and military aircraft.
[10] An example of a method used to delineate "significant hazard" is a risk reduction technique used by the military and used widely throughout engineering known as ALARP (As Low As Reasonably Practicable).
A risk is ALARP when it has been demonstrated that the cost of any further Risk reduction, where cost includes the loss of capability as well as financial or other resource costs, is grossly disproportionate to the benefit obtained from that Risk reduction.’ In the U.S. Code of Federal Regulations, Title 14, Part 23, § 23.200, states, for the purposes of this part, the following definition applies: "Continued safe flight and landing means an airplane is capable of continued controlled flight and landing, possibly using emergency procedures, without requiring exceptional pilot skill or strength.
In Canada Canadian Aviation Regulations, CAR 101.01, Subpart 1 - Interpretation Content last revised: 2007/12/30 "airworthy" - in respect of an aeronautical product, means in a fit and safe state for flight and in conformity with its type design.
