The concept and principle of seaworthiness-the origin and development of seaworthiness

Airworthiness refers to the quality of safety and physical integrity of the overall performance and handling characteristics of civil aircraft (including its components and subsystems) under the constraints of expected operating environment and service conditions. This quality requires that the aircraft should always conform to its model design in the whole life stage and always be in a safe operation state.

Airworthiness management is a technical management aimed at ensuring the safety of civil aircraft. It is a scientific and unified review, appraisal, supervision and management of the design, manufacture, use and maintenance of civil aircraft by the government airworthiness department on the basis of formulating various minimum safety standards.

The purpose of airworthiness management is to ensure aviation safety, safeguard public interests and promote the development of civil aviation. According to the different management contents and implementation stages, airworthiness management can be divided into initial airworthiness management and continuous airworthiness management.

Airworthiness certification is a part of the initial airworthiness management, which means that before the aircraft is delivered for use, the airworthiness management department reviews, appraises, supervises and manages the design and manufacture of civil aircraft (including its components and systems) according to airworthiness regulations, procedures and standards, so as to ensure that the design and manufacture of aircraft and aircraft components meet the minimum safety standards stipulated in airworthiness regulations.

At present, the accident rate of commercial jets is about 0.24/ million flight hours. In 2007, the fatality rate in North America was about 0.05/ million flight hours, while that in other parts of the world was about 0.33/ million flight hours. It can be seen that the safety level of air transportation in North America is much higher than that in other parts of the world.

Aircraft accident factors: accident, security, aircraft, collision, weather, crew, take-off/landing, fire, maintenance, external events, air traffic control and navigation, cargo and unknown factors. (The factors are sorted from high to low according to the proportion of occurrence).

Aircraft itself: engine, fuselage, landing gear, control surface, system, instrument and booster. (The factors are sorted from high to low according to the proportion of occurrence).

Because the accidents caused by aircraft design and manufacturing itself account for about 10% of the total accidents, the accident rate caused by aircraft design and manufacturing itself is about 0.024/ million flight hours.

For newly designed aircraft, the probability of serious accidents caused by all aircraft systems should not exceed 0. 1 time per million hours.

The upper limit of the average probability of catastrophic failure state per million hours is 0.00 1.

Zhao yuerang. Concept and Principle of Airworthiness [M], Shanghai Jiaotong University Press.2013.