CFN – Pilot Dan Baz is answering your flying questions here on the Cornwall Free News. If you have a question about flying you can email Captain Dan or post below.
Question
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Is there cruise control on airplanes, similar to what I have on my car ?Question asked by Orly.
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Answer
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Yes, there is a system on airplanes that is similar to a cruise control on cars, however the system is more sophisticated and complex, because an airplane operates in a three dimensional environment. The system is called Auto Throttle or Auto Thrust control system.
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Not all airplanes have it. Those that do not, engine thrust is controlled manually by pilots, using thrust levers located on the console between the two pilot seats. However, all large Boeing and Airbus airline jets have the automatic thrust control system, as well as manual thrust levers, as a back up, should the automatic thrust control system fail.
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Basically the system controls the thrust of the engines. It operates in two modes. Thrust mode and speed mode. The thrust mode is used for take-off, climb and descent phases of flight, the speed mode is used for a cruise (level) flight and approach to a runway.
For take-off, the system will set the engines to the required take-off thrust, calculated by the pilots, based on current environmental and runway conditions. Once the airplane is airborne, the thrust is reduced to climb thrust setting, which is approximately 75% of the engine full thrust rating. When the airplane levels off at altitude in cruise flight, the system is switched to a speed control mode.
For take-off, the system will set the engines to the required take-off thrust, calculated by the pilots, based on current environmental and runway conditions. Once the airplane is airborne, the thrust is reduced to climb thrust setting, which is approximately 75% of the engine full thrust rating. When the airplane levels off at altitude in cruise flight, the system is switched to a speed control mode.
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For descent the system goes back to the thrust mode, however the engine thrust is set to idle thrust and the airplane basically glides toward the airport. Idle thrust descents are used for fuel efficiency. On the approach to a runway, the thrust control system will be used in speed mode, to maintain approach speed selected by the pilots.
A bit more about Captain Dan:
Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.
Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.
