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A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the additional fan stage. It consists of a gas turbine engine which achieves mechanical energy from combustion, and a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.
Aircraft engine controls provide a means for the pilot to control and monitor the operation of the aircraft's powerplant. This article describes controls used with a basic internal-combustion engine driving a propeller. Some optional or more advanced configurations are described at the end of the article. Jet turbine engines use different operating principles and have their own sets of controls and sensors.
An afterburner is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. The afterburning process injects additional fuel into a combustor in the jet pipe behind the turbine, "reheating" the exhaust gas. Afterburning significantly increases thrust as an alternative to using a bigger engine with its attendant weight penalty, but at the cost of increased fuel consumption which limits its use to short periods. This aircraft application of "reheat" contrasts with the meaning and implementation of "reheat" applicable to gas turbines driving electrical generators and which reduces fuel consumption.
A full authority digital enginecontrol (FADEC) is a system consisting of a digital computer, called an "electronic engine controller" (EEC) or "engine control unit" (ECU), and its related accessories that control all aspects of aircraft engine performance. FADECs have been produced for both piston engines and jet engines.
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. Such devices affect the aircraft significantly and are considered important for safe operations by airlines. There have been accidents involving thrust reversal systems, including fatal ones.
The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft, also known as the maximum structural takeoff weight or maximum structural takeoff mass, is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. The analogous term for rockets is gross lift-off mass, or GLOW. MTOW is usually specified in units of kilograms or pounds.
In aviation, hot and high is a condition of low air density due to high ambient temperature and high airport elevation. Air density decreases with increasing temperature and altitude. The lower air density reduces the power output from an aircraft's engine and also requires a higher true airspeed before the aircraft can become airborne. Aviators gauge air density by calculating the density altitude.
A propelling nozzle is a nozzle that converts the internal energy of a working gas into propulsive force; it is the nozzle, which forms a jet, that separates a gas turbine, or gas generator, from a jet engine.
A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. The severity of the phenomenon ranges from a momentary power drop barely registered by the engine instruments to a complete loss of compression in case of a surge, requiring adjustments in the fuel flow to recover normal operation.
A compressor map is a chart which shows the performance of a turbomachinery compressor. This type of compressor is used in gas turbine engines, for supercharging reciprocating engines and for industrial processes, where it is known as a dynamic compressor. A map is created from compressor rig test results or predicted by a special computer program. Alternatively the map of a similar compressor can be suitably scaled. This article is an overview of compressor maps and their different applications and also has detailed explanations of maps for a fan and intermediate and high-pressure compressors from a three-shaft aero-engine as specific examples.
A jet engine performs by converting fuel into thrust. How well it performs is an indication of what proportion of its fuel goes to waste. It transfers heat from burning fuel to air passing through the engine. In doing so it produces thrust work when propelling a vehicle but a lot of the fuel is wasted and only appears as heat. Propulsion engineers aim to minimize the degradation of fuel energy into unusable thermal energy. Increased emphasis on performance improvements for commercial airliners came in the 1970s from the rising cost of fuel.
A takeoff/go-around switch is a switch on the autothrottle of modern large aircraft, with two modes: takeoff (TO) and go-around (GA). The mode is dependent on the phase of flight; usually, on approach to land, the autopilot will be set to approach mode, therefore if the TO/GA switch is pressed it will activate the go-around mode of the autothrottle (about 90–92% N1, if pressed again, go around thrust will increase to full ; conversely, when takeoff is set on the autopilot, the switch activates takeoff mode of the autothrottle. On Boeing aircraft, TO/GA modes are selected by a separate button near the throttle levers; on Airbus aircraft, it is activated by advancing the thrust levers forward to the TO/GA detent.
In aviation, a rejected takeoff (RTO) or aborted takeoff is the situation in which the pilot decides to abort the takeoff of an airplane after initiating the takeoff roll but before the airplane leaves the ground.
TAM Transportes Aéreos Regionais Flight 402 was a scheduled domestic flight from Caxias do Sul, Brazil, to Recife International Airport in Recife, via São Paulo–Congonhas International Airport and Santos Dumont Airport in Rio de Janeiro. On 31 October 1996, at 8:27 (UTC-2), the starboard engine of the Fokker 100 operating the route reversed thrust while the aircraft was climbing away from the runway at Congonhas. The aircraft stalled and rolled beyond control to the right, then struck two buildings and crashed into several houses in a heavily populated area only 25 seconds after takeoff. All 95 people on board were killed, as well as another 4 on the ground. It is the fourth deadliest accident in Brazilian aviation history, the second at the time. It is also the deadliest aviation accident involving a Fokker 100.
Airbus Industrie Flight 129 was an Airbus Industrie A330-321 test flight that ended in a crash on 30 June 1994 at Toulouse–Blagnac Airport, killing all seven people aboard. The last test flown was to certify the plane's takeoff capability with a single engine failure. It was the first fatal accident involving an Airbus A330 as well as the first hull loss of the type. It remained the only fatal accident involving an A330 until the crash of Air France Flight 447 on 1 June 2009.
British Airways Flight 38 was a scheduled international passenger flight from Beijing Capital International Airport in Beijing, China, to London Heathrow Airport in London, United Kingdom, an 8,100-kilometre trip. On 17 January 2008, the Boeing 777-200ER aircraft operating the flight crashed just short of the runway while landing at Heathrow. No fatalities occurred; of the 152 people on board, 47 sustained injuries, one serious. It was the first time in the aircraft type's history that a Boeing 777 was declared a hull loss, and subsequently written off.
This article briefly describes the components and systems found in jet engines.
RwandAir Flight 205 was a Canadair CRJ100ER that crashed into the Terminal Building after an emergency landing at Kigali, Rwanda killing one passenger. The flight was operated by JetLink Express on behalf of RwandAir. In the aftermath of the accident, RwandAir suspended all operations with JetLink Express.
On April 4, 1955, a United Airlines Douglas DC-6 named Mainliner Idaho crashed shortly after taking off from Long Island MacArthur Airport, in Ronkonkoma, Islip, New York, United States.
On 18 May 2016, a Silk Way Airlines Antonov An-12 cargo plane crashed after an engine failure during the take off run at Dwyer Airport in southern Afghanistan, en route to Mary International Airport in Turkmenistan. Seven of the nine crew members on board were killed in the crash, which was the second incident for Silk Way in Afghanistan after a 2011 Il-76 crash. The two survivors were taken to hospital and treated for their injuries.
References
- ↑ "Reduced Thrust Takeoff". 30 May 2021.
- ↑ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 222. ISBN 9780850451634.
- ↑ "Flex temperature, choice of takeoff configuration" (PDF).
- ↑ "Photo Search Results" . Retrieved 2010-10-10.
- ↑ AAIB Bulletin: 11/2009. "AAIB Bulletin: 11/2009", UK Air Accidents Investigation Branch, 2009. Retrieved on 2009-12-20.