2. BACKGROUND
The Government of Japan has been requiring Japanese air carriers to report PDAs (Parts Departing Aircraft) since 2009. Although the number of reported PDAs decreased slightly after that, it increased in 2017.
Japan has already implemented various measures against objects falling off airplanes. For example, completing drainage of water in the water supply pipes before take-off to prevent ice blocks from falling off, requesting air carriers to complete maintenance and safety inspections, and requesting aircraft manufacturers to improve designs and prevent incidences of falling parts.
However, recent serious occurrences of objects falling off airplanes has raised huge public attention. In September 2017, a large panel fell from an airplane onto a car driving on a busy street in Osaka. In May 2018, an airplane that had just taken off at Kumamoto Airport experienced engine failure, and more than 100 metallic fragments, which are suspected to have been part of the engine, fell onto the ground, houses, and cars below. Fortunately, no one was injured, but the incident caused the damage of a window in a hospital, windows of cars, etc. These events were broadly reported to the public by the mass media. There have been other recent cases of damage caused by objects falling off airplanes in addition to those mentioned above. Moreover, not only airplane parts, but also ice blocks sometimes have fallen onto the ground. Therefore, anxiety and concern of residents toward objects falling off airplanes has been augmented.
