A forced landing is a landing by an aircraft made under factors outside the pilot's control, such as the failure of engines, systems, components or weather which makes continued flight impossible. For a full description of these, see article on emergency landing. However the term also means a landing that has been forced by interception.
A plane may be compelled to land through the use, or threat of use, of force, if it strays off course into hostile foreign territory. The customary procedure is for the military plane to approach the airliner from below and to the left, where his plane is easily visible from the left seat where the captain sits. The forcing plane waggles his wings to signal the demand for a forced landing.
International law regulates the treatment of intruding aircraft: