How much is auto pilot used on a standard flight?

Do they use it to taxi and follow the perfect line?

Takeoff is manual.

When is auto pilot initiated after take off, how long after, is it used for the climb?

Do they use it to keep in line with the runway for landing/ or how long up until landing do they use it till?

Thanks : )

9 Answers

  • Anonymous
    10 years ago
    Favorite Answer

    There are some good answers here. I thought I'd add a few of my own.

    "Do they use it to taxi and follow the perfect line?" No, for two reasons: One is that there isn't really a technology that exists that can lock on to an airplane and steer it around the taxiways to and from the gate... and if there was and it happened to malfunction, think about how dangerous that would be. Secondly, an AP isn't necessary for taxi. All you're doing when you taxi an airplane is steer it, brake it, and give it some gas...kind of like a car. With two pilots at the helm, they can do a much better job at this than a robot pilot.

    "Takeoff is manual." Correct, in the sense that the pilots have to set the throttles, pull back on the control column or stick, lift the airplane off the ground, and raise the landing gear. At what point the takeoff ends and the climb phase begins is a matter of debate, but once the gear is up and the airplane has cleared any obstacles, this is really where climb begins and the AP CAN be immediately armed for flight control, though most airlines have a minimum altitude policy of at least a few thousand feet for safety, should the AP malfunction. However, modern airliner autopilots also have a feature called AUTOTHROTTLE, which is typically engaged as soon as the airplane begins its takeoff roll. It takes over throttle control so that the pilots can concentrate on other things like the control column, gear, and flaps. So there is a component of the AP that is typically active even before the airplane leaves the ground.

    "When is auto pilot initiated after take off, how long after, is it used for the climb?" I think others have answered this question pretty well. I'll just add that even though some pilots might WANT to hand fly the airplane all the way up to altitude (believe me, if you're tired and have to fight a winter storm climbing out of O'Hare International, you will NOT), most airlines prefer and some require that you let the AP do the job. This is because the AP and all the associated computers onboard can "sense" everything that is happening instantly and more efficiently than a human pilot, and can (usually) fly the airplane more efficiently, which translates into better fuel economy, thus lower operating costs.

    "Do they use it to keep in line with the runway for landing/ or how long up until landing do they use it till?" Again there were good answers here. It's mostly a matter of what the pilots want to do. The captain might let a young gun copilot take the plane from top of descent all the way to landing, a phase that might start 80 miles away from the airport. On the other hand, at the end of a 10 hour flight, with both pilots tired and shitty weather conditions at the destination, the AP will surely be used from top of descent to at least the final approach segment. (This typically begins when the airplane is pointed straight at the runway, has been slowed down a bit, and is "locked on" to the glide slope). From this point, the pilots may switch off the AP and hand fly, or allow the AP to fly the plane down to a hundred feet or so before going manual. What keeps the airplane ALIGNED WITH THE RUNWAY, however (assuming distance and/or weather prevent the pilot from seeing it), is part of the navigation system, not the AP. The AP just moves the airplane up, down, left, and right. It doesn't know where it's steering the plane, or how far it has to go. That's up to navigation and other computers, which in turn send commands to the AP. A particular runway will have an antenna array nearby that sends a focused signal to the airplane on final approach. The airplane's nav sensors receive this signal, so that the airplane can "home in" on the runway. As another person mentioned, this is called an ILS system. If the AP is in control, it tracks this signal to the runway automatically. If the pilots are landing the plane (happens most of the time), they too follow the signal via their navigation instruments, but make the flight control movements on their own.

    With all us pilots weighing in, by now you ought to be an expert! Thanks all.

    Source(s): Oh, I've flown a bit.
  • Zander
    Lv 4
    10 years ago

    The Autopilot isn't used for an alignment with the Runway, this is done with the assistance of Centreline lighting.

    The Autopilot is generally programmed whilst the aircraft is sat on the ground generally at the gate and will be set in accordance with the filed Flight Plan.

    Once the aircraft has departed and the flight plan details such as Initial Heading and Initial Altitude has been clarified with the controller then this is the point when the aircraft's Autopilot Command is activated.

    The autopilot is then used for much of the descent, sometimes it is used up until Short Final 5NM.

    This is when the pilot will take manual control over the primary flight controls such as Pitch, Bank and Yaw.

    He will also take control of the Flaps and throttle and arm the Speedbrakes and Autobrakes.

    If conditions do not permit VMC (Visual Meteorological Conditions) this would be things such as Heavy Rain, Fog, Snow then the pilot would use something called the ILS.

    This stands for Instrument Landing System and it essentially gives the pilot the Centreline of the runway and the profile which is the Glideslope of the Runway.

    And the pilot may wish to use the DME (Distance Measuring Equipment) which gives him a precise distance from the runway and is used for the setting of flaps and other things.

  • 10 years ago

    There are proof-of-concept systems that will pilot a plane automatically from gate to gate, but they are not currently implemented or feasible for real-world commercial use.

    Pilots taxi the aircraft manually. Takeoff is manual also. The autopilot and flight management computers are given control shortly after takeoff, depending on a number of factors (pilot preferences, airline policies, etc.). The computers remain in control until late in the final approach, when the pilots take over (except for autolands in poor weather, in which case the computers fly the airplane all the way down to the runway). The point at which the computers are turned off for arrival depends again on pilot preference, airline policies, and so on. At the very latest, the automation must be turned off to land the plane manually, but in some cases pilots will turn the computers off not long after the descent is begun.

    An autoland will keep the aircraft aligned with the runway after touchdown. Otherwise the pilots keep the aircraft aligned manually after they touch down.

  • 10 years ago

    It will vary by airplane, company, and pilot.

    All taxiing is done manually.

    All takeoffs are hand flown.

    Sometimes autopilot is engaged a couple hundred feet off the ground after takeoff. Sometimes pilots hand fly an airplane until passing 10,000 feet.

    After the autopilot is engaged, it is rarely disengaged until preparing for landing. If the weather is good, some pilots will hand fly below 10,000 feet. Some will hand fly below 1,000 feet. The autopilot is almost always disconnected by 200 feet. If the weather is really low, the airplane is capable, and the crew is trained, an autoland may be performed, in which case the autopilot is disconnected after landing but before turning off the runway. This isn't done very often.

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  • Anonymous
    10 years ago

    Pilots make all takeoffs and all but a few landings. Autopilot is used only in flight, from shortly after takeoff until arriving in the terminal area at the destination..

    The autopilot will naviagate using standard VOR/ILS signals, or using a preprogrammed flight plan from a Flight Management System (FMS), if installed.

    Depending on the unit, FMS programming can include lateral (LNAV) and/or vertical (VNAV) navigation.

    Some airplanes are equipped with autoland capability, which allows the airplane to land itself in low visibility conditions.

  • Anonymous
    10 years ago

    When I was flying, I would engage the A/P when reaching climb speed -

    For a heavy 747, it is something like 330 or 340 KIAS -

    And for approach, I would fly manually from outer marker if in VMC -

    In case of reduced visibility, until I have the runway in sight -

    In RVSM, we require A/P ON at all time for altitude hold precision -

    Source(s): Retired airline pilot
  • Brenda
    Lv 4
    4 years ago

    The above is correct. Most autopilot landing are taken to the minimum, and then hand flown the rest of the way.

  • 10 years ago

    depends oin big beoings the are from start to after landing provided the a/c is cat3

  • 10 years ago


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