Aviation
 |
First flight, December 17, 1903 |
Aviation or
air transport refers to the activities surrounding human
flight and the
aircraft industry. Aircraft include
fixed-wing aircraft, rotary wing (
helicopter/
autogyro) types, and
ornithopters, as well as lighter-than-air craft such as
balloons and
airships (also known as dirigibles).
Main article: History of aviation
There are records of early, short-distance glider flights from the 10th and 11th centuries, and possibly earlier human-carrying kites from
China, but practical human aviation (trips lasting more than a few seconds) began on
November 21 1783 with the first untethered human flight in a hot air balloon designed by the
Montgolfier brothers. A little over a century later, on
December 17 1903, the
Wright brothers flew the first successful powered, heavier-than-air flight, though their aircraft was impractical to fly for more than a short distance, due to control problems. The widespread adoption of
ailerons made aircraft much easier to manage, and only a decade later, at the start of
World War I, heavier-than-air powered aircraft had become practical for reconnaissance, artillery spotting, and even attacks against ground positions.
Between the wars, aircraft grew larger and more reliable, and began to be used to transport people and cargo. In the 1930s, the
Douglas DC-3 was the first
airliner that was profitable carrying passengers exclusively, starting the modern era of passenger airline service. By the beginning of
World War II, many towns and cities had built airports, and there were a large number of qualified pilots available. The war brought many innovations to aviation, including the first
jet aircraft and the first liquid-fueled
rockets.
After the war, especially in North America, there was a boom in
general aviation, both private and commercial, as thousands of pilots were released from military service and many inexpensive war-surplus transport and training aircraft were available. Small aircraft manufacturers such as
Cessna,
Piper, and
Beechcraft expanded production to provide small aircraft for the new middle class market.
By the 1950s, the development of civil jets grew, beginning with the
de Havilland Comet, though the first widely-used passenger jet was the
Boeing 707. At the same time,
turboprop propulsion began to appear for smaller commuter planes, making it possible to serve small-volume routes in a much wider range of weather conditions.
Yuri Gagarin was the first human to travel to space on
April 12,
1961 while the
Apollo 11 crew first were the first to set foot on the moon on
July 21,
1969.
Since the 1960s,
composite airframes and quieter, more efficient engines have become available, but the most important innovations have taken place in instrumentation and control. The arrival of
solid-state electronics, the
Global Positioning System,
satellite communications, and increasingly small and powerful
computers and
LED displays, have dramatically changed the cockpits of
airliners and, increasingly, of smaller aircraft as well. Pilots can navigate much more accurately and view terrain, obstructions, and other nearby aircraft on a map or through
synthetic vision, even at night or in low visibility.
On
June 21 2004,
SpaceShipOne became the first privately-funded aircraft to make a
spaceflight, opening the possibility of an aviation market outside the earth's atmosphere.
Main article: Civil aviation
Civil aviation includes all non-military flying, both
general aviation and
scheduled air transport.
Commercial transport
Main article: Airline
While there were many more in the past, there are currently only five major manufacturers of transport aircraft:
*
Boeing, based in the
United States*
Airbus, based in Europe (primarily
France)
*
Bombardier, based in
Canada*
Embraer, based in
Brazil*
Tupolev, based in
RussiaBoeing, Airbus, and Tupolev concentrate on larger
airliners, while Bombardier and Embraer concentrate on commuter aircraft.
Until the 1970s, most major airlines were
flag carriers, sponsored by their governments and heavily protected from competition. Since then, various
open skies agreements have resulted in increased competition and choice for consumers, coupled with falling prices for airlines. The combination of high fuel prices, low fares, high salaries, and crises such as the
September 11, 2001 attacks and the
SARS epidemic have driven many older airlines to government-bailouts, bankruptcy or mergers. At the same time,
low-cost carriers such as
Ryanair and
Southwest have flourished.
General Aviation
Main article: General aviation
 |
1947 Cessna 120 |
General aviation includes any flight that is not
military and does not fly on a regular
schedule, ranging from a recreational flight in a
hang glider to a non-scheduled cargo flight in a
Boeing 747. The majority of flights on any day will fall into this category.
Because of the huge range of activities, it is difficult to cover general aviation with a simple description — general aviation may include business flights, private aviation, flight training, parachuting, gliding, air ambulance, crop dusting, charter flights, traffic reporting, police air patrols, forest fire flighting, and many other types of flying.
Each country regulates aviation differently, but typically, general aviation falls under several different types of regulations depending on whether it is private or commercial and on the type of equipment involved.
Many small aircraft manufacturers, including
Cessna,
Piper,
Mooney,
Cirrus Design,
Raytheon, and others serve the general aviation market, with a focus on private aviation and flight training. The most important recent developments for small aircraft have been the introduction of advanced
avionics (including
GPS) that were formerly found only in large
airliners, and the introduction of
composite materials to make small aircraft lighter and faster.
Main article: Military Aviation
|
The Lockheed SR-71 was remarkably advanced for its time and remains unsurpassed in many areas of performance. |
Simple
airships were used as surveillance aircraft as early as the 18th century. Over the years,
military aircraft have been built to meet ever increasing capability requirements. Manufacturers of military aircraft compete for contracts to supply their government's arsenal. Aircraft are selected based on factors like cost, performance, and the speed of production.
Types of military aircraft
*
Fighter aircraft's primary function is to destroy other aircraft. (e.g.
F-16,
MiG-29, and the
Mirage 2000])
*
Ground attack aircraft are used against
tactical earth-bound targets. (e.g.
Su-25,
A-10, and the
F/A-18)
*
Bombers are generally used against more
strategic targets. (e.g.
Tu-22,
Tu-160,
B-24, and the
B-52)
*
Surveillance aircraft have special capabilities used for
reconnaissance (e.g.
U-2,
MiG-25R and
SR-71)
Main article: Air traffic control
Air traffic control (ATC) involves humans (typically on the ground) who communicate with aircraft to help maintain
separation — that is, they ensure that aircraft are far enough apart horizontally or vertically that there is no risk of collision. Controllers may co-ordinate position reports provided by pilots, or in high traffic areas (such as the
United States) they may use
RADAR to see aircraft positions.
While the exact terminology varies from country to country, there are generally three different types of ATC:
* control towers (including tower, ground control, clearance delivery, and other services), which control aircraft within a small distance (typically 10-15 km horizontal, and 1,000 m vertical) of an airport.
* terminal controllers, who control aircraft in a wider area (typically 50-80 km) around busy airports
* centre controllers, who control aircraft enroute between airports
ATC is especially important for aircraft flying under
Instrument flight rules (IFR), where they may be in weather conditions that do not allow the pilots to see other aircraft. However, in very high-traffic areas, especially near major airports, aircraft flying under
Visual flight rules (VFR) are also required to follow instructions from ATC.
In addition to separation from other aircraft, ATC may provide weather advisories, terrain separation, navigation assistance, and other services to pilots, depending on their workload.
It is important to note that ATC does not control all flights. The majority of VFR flights in North America are not required to talk to ATC at all (unless they're passing through a busy terminal area or using a major airport), and in many areas, such as northern
Canada, ATC services are not available even for IFR flights at lower altitudes.
*
List of aviation topics*
Timeline of aviationzh-yue:航空
