Sunday, September 12, 2010




Gangadhar B Kallur


Abstract - This paper gives overall history of Autopilot. In the early days of aviation, aircraft required the continuous attention of a pilot in order to fly safely. As aircraft range increased allowing flights duration of many hours, the constant attention of the pilot led to serious fatigue. An autopilot is designed to perform some of the tasks of the pilot.


The first aircraft autopilot was developed by Sperry Corporation in 1912. The autopilot connected a ‘gyroscopic heading indicator’ and ‘attitude indicator’ to hydraulically operated elevators and rudder. (ailerons were not connected as wing dihedral was counted upon to produce the necessary roll stability.) It permitted the aircraft to fly straight and level on a compass course without a pilot's attention, greatly reducing the pilot's workload.

Lawrence Sperry (the son of famous inventor Elmer Sperry) demonstrated it two years later in 1914. At an aviation safety contest held in Paris, Lawrence Sperry demonstrated the credibility of the invention were he showed the flying of aircraft with his hands away from the controls and visible to onlookers of the contest. This autopilot system was also capable of performing take-off and landing. The French military command showed immediate interest in the autopilot system. Wiley Post used a Sperry autopilot system to fly alone around the world in less than eight days in 1933. Further developments of the autopilot were performed, such as improved control algorithms and hydraulic servomechanisms. Also, inclusion of additional instrumentation such as the radio-navigation aids made it possible to fly during night and in bad weather.

In 1947 a US Air Force C-53 made a transatlantic flight, including takeoff and landing, completely under the control of an autopilot.
In the early 1920s, the Standard Oil tanker J.A Moffet became the first ship to use an autopilot.

Famous inventor and engineer Elmer Sperry patented the gyrocompass in 1908, but it was his son, Lawrence Burst Sperry, who first flight-tested such a device in an aircraft. The younger Sperry's autopilot used four gyroscopes to stabilize the airplane and led to many flying firsts, including the first night flight in the history of aviation.

Some of the inventions in the later years:

1908 - Anschuts Gyro Compass

1911 - Sperry Gyro Compass

1912 - First aircraft autopilot was developed by Sperry Corporation. The demonstration of which was done by Lawrence Sperry in later two years in 1914 and proved the credibility of the invention by flying the aircraft with his hands away from the controls and visible to onlookers.

The autopilot connected a gyroscopic Heading indicator and attitude indicator to hydraulically operated elevators and rudder (ailerons were not connected as wing dihedral was counted upon to produce the necessary roll stability.) It permitted the aircraft to fly straight and level on a compass course without a pilot's attention, greatly reducing the pilot's workload.

In December, 1931 - For the first time in history, a mechanical autopilot is licensed to fly passengers and airmail. The Department of Commerce permits it to serve as copilot of a large Condor 18 passenger plane of Eastern Air Transport on the New York - Washington route. The device incorporates a Sperry gyroscope and operates all the flight controls of the plane except during take offs and landings. The hope is that the device will relieve human pilots of the strain on long flights or flying in bad weather.

In 1932, the Sperry Gyroscope Company developed the automatic pilot that Wiley Post would use in his first solo flight around the world.

In 1978, the following autopilots were introduced: Amerogen (Model Reference Autopilot), Ohtsu (AR Autopilot), Kallstrom (Self Tuning Autopilot).

The Aircraft and Autopilot Timeline

Figure 1: Autopilot Timeline

The Figure 1. describes the origin and development of the aircraft autopilot life cycle with respect to the timelines (1900-2010).
Below is the more description regarding the life cycle of autopilot:

• In 1267, english philosopher Roger Bacon describes flying machines in his Opus Majus.

• In 1505, lonardo da Vinci presents in his Codex on the Flight of Birds plans for flying machines, helicopters and light hang gliders.

• In 1670, francesco Lana de Terzi shows a flying ship in his book Prodomo.

• In 1709, Bartolomeu Laurenço de Gusmão demonstrates hot air balloons.

• In 1783, frenchman inventor Jacques Charles makes the first flight with a hydrogen balloon. Jean-François Pilâtre de Rozier and François Laurent make the first Montgolfier hot-air balloon flight.

• In 1785, frenchman Jean-Pierre Blanchard and American John Jeffries cross the English Channel in a balloon.

• In 1797, André Jacques Garnerin jumps with a parachute from a balloon.

• In 1843, George Cayley and William Samuel Henson design an aerial carriage.

• In 1852, Frenchman Henri Giffard builds the first steam balloon.

• In 1870, Alphonse Pénaud develops the rubber band helicopter toy.

• In 1891, German engineer Otto Lilienthal studies the aerodynamic effects of wing shapes.

• In 1896, Samuel Langley launches his first steam engine-powered unmanned aircraft.

• In 1901, Brazilian Santos-Dumont flies around the Eiffel tower in Paris.

• In 1903, Wilbur and Orville Wright fly a man-controlled airplane.

• In 1904, German professor of mechanics Ludwig Prandtl researches the aerodynamics of an aircraft wing.

• In 1905, The Flyer III is built by the Wright brothers.

• In 1908, first army pilots. First passenger flight. First female airplane passenger.

• In 1909, Eugène Lefèbvre becomes the first pilot of a powered airplane to be killed in flight. French pilot Louis Bleriot crosses for the first time the English Channel. First rotary-winged aircraft. First woman pilot American Geneve Shaffer.

• In 1910, Walter Brookins sets an altitude record with 6,234 feet.

• In 1911, U.S. Army military flight school is founded. Retractable landing gear is invented.

• In 1913, First aerial advertising aka sky writing.

• In 1914, automatic pilot principle discovered, later in airplane timeline 2 this invention will be improved.

• In 1916, altitude record of 16,072 feet was set. The Sperry Aerial Torpedo tests were the first guided missile program in this country.

• In 1916, Lawrence Sperry, developer of the autopilot, formed a new company and set up flying. Nicknamed Bug, the aerial torpedo was launched from a dolly running down a track pointed precisely in the direction of the target.

• In 1917, Aircraft Manufacturers association is established. German mechanics scientist Hugo Junkers creates Junkers J4.

• In 1919, first plane crossing the Atlantic Ocean nonstop, from Newfoundland to Ireland.

• In 1921, first refueling in the air aerial. The pressurized cabin airplane is used.

• In 1924, an airplane flies for the first time over the North Pole.

• In 1927, Charles Lindbergh makes the first solo non-stop trans-Atlantic flight from New York to Paris in the Spirit of St Louis. This event is a historical milestone.

• In 1928, the electromechanical flight simulator is invented. First woman crosses the Atlantic Ocean by air.

• In 1929, an airplane flies for the first time over the South Pole. Endurance record with a Fokker C-2A 172, the craft fklieshours, 176 hours 321 minutes and 2 seconds non-stop.

• In 1930, British mechanic Frank Whittle creates the jet engine.

• In 1931, Glider flight with a rocket powered engine.

• In 1932, Non-stop transatlantic solo flight by Amelia Earhart in a Lockheed Vega 5B from Los Angeles to Newark.

• In 1933, The Boeing 247, the Douglas RD-2 Dolphin presidential air plane, and the Douglas DC-1 are introduced.

• In 1935, Douglas DC-3 passenger airliner presented.

• In 1937, Jet engines are improved.

• In 1938, Lockheed 14 sets a global speed record in 3 days, 19 hours and 8 minutes.

• In 1939, Boeing B-17 Flying Fortress. Many air battles during World War II. Russian-born Igor Sikorsky creates the US Army VS-300 single main rotor helicopter. Germany contructs the Heinkel 178 fighter.

• In 1940, The autopilot is improved.

• In 1944, Northrop MX-334 rocket driven airplane was introduced. Developed an electronic autopilot a wartime improvement of the automatic pilot.

• In 1946, Douglas XB-43 jet bomber.

• In 1947, The Bell X-1 flies faster than sound.

• In 1950, Boeing B-52 bomber developed.

• In 1951, Kaman K-225 gas-turbine helicopter and the Boeing's B-47 bomber are built.

• In 1952, British BOAC presents the De Havilland Comet, the first of a series in airplane timeline. American Richard Whitcomb discovers the area rule for designing aircrafts.

• In 1953, Bell X-1A and Douglas D-558-2 fly Mach 2.

• In 1954, Kaman HTK-1 twin-turbine helicopter presented.

• In 1957, Dwight D Eisenhower from now on uses a helicopter, the Bell H-13J. Canadian pilot Jacqueline Cochran sets the most speed, altitude and distance records ever in the airplane timeline history.

• In 1958, Pan American opens its international commercial service with a Boeing 707-121.

• In 1959, McDonnell XF-4H-1 sets a new altitude record of 98,556 feet.

• In 1961, McDonnell XF-4H-1 sets a new speed record of 16,063 miles per hour.

• In 1964, Geraldine Mock makes the first female Solo flight around the world.

• In 1965, Lockheed A-12/SR-71 reaches Mach 3.

• In 1969, Boeing 747 presented.

• In 1975, CESSNA 150 PLANE SURE FLYERS WITH AUTO PILOT Learn the thrills of model flying quickly. This Cessna has an automatic pilot that can be switched on to control this model airplane through takeoff flight and landing.

• In 1979, Use of the autopilot enables the pilot to spend more time on other necessary aspects of the flight process. When the weather is bad the autopilot can take on the otherwise tiring job of maintaining a smooth ride Other than a lighted switch on the control panel the autopilot is quite.

• In 1990, Lockheed SR-71 Blackbird sets a transcontinental speed record of Mach 28 or 2, 12405 miles per hour.

• In 1990, Lockheed creates the Stealth F-117 fighter.

• In 1994, Boeing 777-200.

• In 1995, Boeing 777.

• In 1996, American and Russian aerospace companies develop the second-generation supersonic jetliner.

• In 2000, Concorde crash in Paris.

• In 2005, Steve Fossett makes a non-stop non-refueled solo flight around the world.

• In 2007, Garmin's GHP 10 Marine Autopilot is a new generation of the TR-1 Gladiator autopilot which has become very popular in US. Garmin acquired the assets of Nautamatic Marine Systems, developer of the TR-1, in March 2007. This new system for hydraulically-steered boats will feature Shadow Drive, a patented capability that automatically disengages the autopilot if the helm is turned, allowing for quick manual manoeuvres.

• In 2008, A Singapore-bound Qantas jet carrying 277 passengers was forced to turn back to the west-coast city of Perth early on December 27 2008, after the aircraft's auto pilot disconnected. The plane was about 260 nautical miles (416 kilometers) north-west of Perth when the malfunction occurred, disrupting the supply of key information to flight control computers.

Modern autopilots:

An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. An autopilot can refer specifically to aircraft, self-steering gear for boats, or auto guidance of space craft and missiles. The autopilot of an aircraft is sometimes referred to as "George."

Figure 2: Autopilot panel

Not all of the passenger aircraft flying today have an autopilot system. Older and smaller general aviation aircraft especially are still hand-flown, while 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.

There are three levels of control in autopilots for smaller aircraft.

1. A single-axis autopilot controls an aircraft in the roll axis only; such autopilots are also known colloquially as "wing levelers", reflecting their limitations.

2. A two-axis autopilot controls an aircraft in the pitch axis as well as roll, and may be little more than a "wing leveler" 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.

3. A three-axis autopilot adds control in the yaw axis and is not required in many small aircraft.

Autopilots in modern complex aircraft are three-axis and generally divide a flight into taxi, takeoff, ascent, level, descent, approach and landing phases. Autopilot automates all of these flight phases except the taxiing. An autopilot-controlled landing on a runway and controlling the aircraft on rollout (i.e. keeping it on the center of the runway) is known as a CAT IIIb landing or Auto land, available on many major airports runways today, especially at airports subject to adverse weather phenomena such as fog.

Landing, rollout and taxi control to the aircraft parking position is known as CAT IIIc. This is not used to date but may be used in the future. An autopilot is often an integral component of a Flight Management System.

Modern autopilots use computer software to control the aircraft. The software reads the aircraft's current position, and controls a Flight Control System to guide the aircraft. In such a system, besides classic flight controls, many autopilots incorporate thrust control capabilities that can control throttles to optimize the air-speed, and move fuel to different tanks to balance the aircraft in an optimal attitude in the air. Although autopilots handle new or dangerous situations inflexibly, they generally fly an aircraft with a lower fuel-consumption than a human pilot.

The autopilot in a modern large aircraft typically reads its position and the aircraft's attitude from an inertial guidance system. Inertial guidance systems accumulate errors over time. They will incorporate error reduction systems such as the carousel system that rotates once a minute so that any errors are dissipated in different directions and have an overall nulling effect. Error in gyroscopes is known as drift. This is due to physical properties within the system, either it is mechanical or laser guided, that corrupt positional data. The disagreements between the two are resolved with digital signal processing, most often a six-dimensional Kalman filter. The six dimensions are usually roll, pitch, yaw, altitude, latitude and longitude. Aircraft may fly routes that have a required performance factor. Therefore the amount of error or actual performance factor must be monitored in order to fly those particular routes. The longer the flight the more error accumulates within the system. Radio aids such as DME and GPS may be used to correct the aircraft position


We understand the timeline of aircrafts and origin of Autopilot and Detailed life cycle of autopilot.


I would like to acknowledge my gratitude for presenting this paper and thank all the Tejasvi Nagananda and My Wife Madhu.


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