Autopilot
The etymology of the nickname is unclear: some claim it is a reference to American inventor George De Beeson (1897 - 1965), who patented an autopilot in the 1930s, while others claim that Royal Air Force pilots coined the term during World War II to symbolize that their aircraft technically belonged to King George VI.
As aircraft range increased, allowing flights of many hours, the constant attention led to serious fatigue.
Sperry demonstrated the credibility of the invention by flying the aircraft with his hands away from the controls and visible to onlookers.
[5] In 1930, the Royal Aircraft Establishment in the United Kingdom developed an autopilot called a pilots' assister that used a pneumatically spun gyroscope to move the flight controls.
In 1947, a U.S. Air Force C-53 made a transatlantic flight, including takeoff and landing, completely under the control of an autopilot.
Older and smaller general aviation aircraft especially are still hand-flown, and even small airliners with fewer than twenty seats may also be without an autopilot as they are used on short-duration flights with two pilots.
The installation of autopilots in aircraft with more than twenty seats is generally made mandatory by international aviation regulations.
A two-axis autopilot controls an aircraft in the pitch axis as well as roll, and may be little more than a wing leveller with limited pitch oscillation-correcting ability; or it may receive inputs from on-board radio navigation systems to provide true automatic flight guidance once the aircraft has taken off until shortly before landing; or its capabilities may lie somewhere between these two extremes.
The aircraft can typically stop on their own, but will require the disengagement of the autopilot in order to exit the runway and taxi to the gate.
An option midway between fully automated flight and manual flying is Control Wheel Steering (CWS).
In CMD (Command) mode the autopilot has full control of the aircraft, and receives its input from either the heading/altitude setting, radio and navaids, or the FMS (Flight Management System).
[12] The hardware of an autopilot varies between implementations, but is generally designed with redundancy and reliability as foremost considerations.
For example, the Rockwell Collins AFDS-770 Autopilot Flight Director System used on the Boeing 777 uses triplicated FCP-2002 microprocessors which have been formally verified and are fabricated in a radiation-resistant process.
[13] Software and hardware in an autopilot are tightly controlled, and extensive test procedures are put in place.
A stability augmentation system (SAS) is another type of automatic flight control system; however, instead of maintaining the aircraft required altitude or flight path, the SAS will move the aircraft control surfaces to damp unacceptable motions.
The most common type of SAS is the yaw damper which is used to reduce the Dutch roll tendency of swept-wing aircraft.
[14] Yaw dampers use a sensor to detect how fast the aircraft is rotating (either a gyroscope or a pair of accelerometers),[15] a computer/amplifier and an actuator.
CAT I – This category permits pilots to land with a decision height of 200 feet (61 m) and a forward visibility or Runway Visual Range (RVR) of 550 metres (1,800 ft).
CAT IIIa -This category permits pilots to land with a decision height as low as 50 feet (15 m) and a RVR of 200 metres (660 ft).
CAT IIIb – As IIIa but with the addition of automatic roll out after touchdown incorporated with the pilot taking control some distance along the runway.
An aircraft that is capable of landing in a CAT IIIb that is equipped with autobrake would be able to fully stop on the runway but would have no ability to taxi.
Fail-operational autopilot: in case of a failure below alert height, the approach, flare and landing can still be completed automatically.
