Mid-air collisionIn aviation, a mid-air collision is an accident in which two or more aircraft come into unplanned contact during flight. Owing to the relatively high velocities involved and the likelihood of subsequent impact with the ground or sea, very severe damage or the total destruction of at least one of the aircraft usually results. The potential for a mid-air collision is increased by miscommunication, mistrust, error in navigation, deviations from flight plans, lack of situational awareness, and the lack of collision-avoidance systems.
Intermodal passenger transportIntermodal passenger transport, also called mixed-mode commuting, involves using two or more modes of transportation in a journey. Mixed-mode commuting is often used to combine the strengths (and offset the weaknesses) of various transportation options. A major goal of modern intermodal passenger transport is to reduce dependence on the automobile as the major mode of ground transportation and increase use of public transport.
Civil aviationCivil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most countries in the world are members of the International Civil Aviation Organization and work together to establish common Standards and Recommended Practices for civil aviation through that agency. Civil aviation includes three major categories: Commercial air transport, including scheduled and non-scheduled passenger and cargo flights Aerial work, in which an aircraft is used for specialized services such as agriculture, photography, surveying, search and rescue, etc.
HailHail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fall in cold weather, while hail growth is greatly inhibited during low surface temperatures. Unlike other forms of water ice precipitation, such as graupel (which is made of rime ice), ice pellets (which are smaller and translucent), and snow (which consists of tiny, delicately crystalline flakes or needles), hailstones usually measure between and in diameter.
Pushback (aviation)In aviation, pushback is an airport procedure during which an aircraft is pushed backwards away from its parking position, usually at an airport gate by external power. Pushbacks are carried out by special, low-profile vehicles called pushback tractors or tugs. Although many aircraft are capable of moving themselves backwards on the ground using reverse thrust (a procedure referred to as a powerback), the resulting jet blast or prop wash would cause increased noise, damage to the terminal building or equipment, and hurt airport staff due to high-speed debris.
Distance measuring equipmentIn aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 960 and 1215 megahertz (MHz). Line-of-visibility between the aircraft and ground station is required. An interrogator (airborne) initiates an exchange by transmitting a pulse pair, on an assigned 'channel', to the transponder ground station.
Air travelAir travel is a form of travel in vehicles such as airplanes, jet aircraft, helicopters, hot air balloons, blimps, gliders, hang gliders, parachutes, or anything else that can sustain flight. Use of air travel has greatly increased in recent decades – worldwide it doubled between the mid-1980s and the year 2000. Modern air travel is much safer than road travel. Air travel are separated into two general classifications: national/domestic and international flights. Flights from one point to another within the same country are domestic flights.
