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Fly-by-light , (dt. About fly by light ) is an optoelectronic , electro-mechanical control systems for aircraft .

In aviation, as in the conventional to place electrical signals over copper wires, fly-by-wire - controls , light signals through optical fibers ( optical fiber cable ) to transmit measurement values and control commands to be used. Conventional electrical signals are only given within the sensors, actuators and computers . However, data is transported over longer distances via fiber optics. Advantages are the reduced weight of the cable and the insensitivity to electromagnetic interference, e.g. B. EMP weapons , radio technology , cell phones . The disadvantage is the additional weight of the optical / electrical converter. B. not used on the Airbus A380 . However, fly-by-light is becoming established in military aircraft ( Northrop B-2 , Kawasaki P-1 ) because it is particularly immune to interference . In the aviation industry, fly-by-light is seen as a growth market.


In 1990, NASA and the US aircraft manufacturer McDonnell Douglas Corp. signed a contract to support the introduction and certification of US- made fly-by-light systems in cargo aircraft . However, the areas of application of this technology were seen not only in aircraft construction, but also in other areas of the US economy. In addition to McDonnell Douglas, other organizations have made technological contributions, namely Honeywell's System and Research Center and Space Systems Group , Electromagnetic Applications (EMA), and Johns Hopkins University.

A US patent was granted on March 30, 1993, according to which it is possible for the pilot to correct the control of the autopilot by means of a fly-by-light system .

In 1995/1996, McDonnell Douglas presented the Fly-By-Light Advanced System Hardware (FLASH) development program to develop a fly-by-light flight control system for military and commercial aircraft (dual use). A primary flight control to regulate the flight attitude and a system of trimming by fly-by-light were demonstrated.


The first voyage of the Sentinel 1000 airship with a fly-by-light control system took place on June 26, 1991.

Experimental helicopter

A research and test helicopter has been in operation at the DLR Aerospace Research Center in Braunschweig since 2002, in which the mechanical control has been removed and replaced by an electrical / optical control with full authority. This helicopter is based on the Type 135 Eurocopter . Digital optical signal transmission has three main advantages: high immunity to electromagnetic interference, secure transmission of large amounts of data and lower weight compared to conventional controls. The first flight was in January 2002. The test helicopter has been in use as a technology demonstrator for years. It was also exhibited at the ILA Berlin 2014.


The Advanced Technologies Testing Aircraft System (ATTAS) was used at DLR from 1985 to 2012. This research aircraft is based on the VFW 614 airliner, a short-haul airliner for up to 44 passengers. The ATTAS was provided with flight test equipment which included an electrohydraulic flight control system in duplex design (fly-by-wire / fly-by-light).

Current state of the art

In September 2007, the Kawasaki XP-1 , a reconnaissance aircraft, had its maiden flight. The XP-1 is considered the first aircraft in the world to be equipped with a fly-by-light control system. In addition, Japan is testing the ATD-X fighter aircraft as a technology demonstrator with fly-by-light; the first flight took place in 2014. Other countries, such as India, are also interested in using this system for military purposes. India has its own fighter aircraft, the Advanced Multirole Combat Aircraft (AMCA), under development. A model was exhibited at Aero India in Bengaluru in 2013. The AMCA is to be equipped with the new control technology.

In 2008, fly-by-light was successfully tested in a Gulfstream Aerospace business aircraft during a 75-minute flight. In the new Boeing 737 , the modernization of which began in 2011, the planned fly-by-wire control has been replaced by fly-by-light.

In December 2014 an Aerospace Information Report was published, which refers to the fly-by-light technology for the control of hydraulically operated flight actuators. This report presents and discusses approaches for corresponding standards in aviation. Fly-by-light technology is also used in small drones .

Web links

Individual evidence

  1. ^ Right Now - Falling by Wire, Falling by Light. In: Retrieved August 25, 2015 .
  2. GKN buys Fokker for £ 500m to bolster aerospace business. Retrieved August 25, 2015 .
  3. ^ Fly-by-Light Technology Development Plan. NASA, August 30, 1990, accessed August 25, 2015 .
  4. Fly by wire / fly by light control system with manual override . ( online [accessed August 25, 2015]).
  5. JR Todd: Fly-by-light flight control system development for transport aircraft . In :, 15th AIAA / IEEE Digital Avionics Systems Conference, 1996 . October 1, 1996, p. 153–158 , doi : 10.1109 / DASC.1996.559149 ( online [accessed August 25, 2015]).
  6. Don J. Halski: Fly-by-light flight control systems . tape 2467 , January 1, 1995, p. 34-45 , doi : 10.1117 / 12.210092 .
  7. ^ New Westinghouse Airship Designed For Early Warning, Surveillance Missions; Aviation Week and Space Technology; Issue of June 8, 1991 pages 24 and 25; (online behind the registration barrier in the archive ); accessed on October 15, 2016
  8. Mario Hamers: FHS - A Fly-By-Light Test Helicopter. Retrieved August 25, 2015 .
  9. ^ Reed Business Information Limited: Fly-by-light EC135 helicopter makes first flight - 2/5/2002 - Flight Global. In: Retrieved August 25, 2015 .
  10. Ten years of flying helicopter simulator (FHS), ten years of his helmsman: an interview with test pilot Uwe Göhmann . ( online [accessed August 25, 2015]).
  11. Aero winner: ILA Berlin 2014: Attractions and travel information for visitors. Retrieved August 25, 2015 .
  12. ^ Deutsches Museum: Deutsches Museum: VFW 614 / ATTAS. In: Retrieved August 25, 2015 .
  13. Japan is modernizing its army with a P-1 reconnaissance aircraft. Retrieved August 25, 2015 .
  14. 'Fly by light' Japanese maritime patrol A / C | Wings Over New Zealand. In: Retrieved August 25, 2015 .
  15. News Desk: Japan's stealth fighter demonstrator on schedule for first flight this year | Defense Update: Retrieved August 25, 2015 .
  16. Why relations with Japan are important. Retrieved August 25, 2015 .
  17. Indian 'Home-Grown' AMCA, An Alternative To FGFA. Retrieved August 25, 2015 .
  18. ^ Gulfstream Demonstrates Fly-By-Light Aircraft Control System. In: Retrieved August 25, 2015 .
  19. Boeing 737 replacement will offer choice of two engines (FlightBlogger). Retrieved August 25, 2015 .
  20. AIR4982A: Aerospace Fly-by-Light Actuation Systems - SAE International. In: Retrieved August 25, 2015 .
  21. ^ Coming US Policy Change Will Free Small Drone Exports. Retrieved August 25, 2015 .