Autoland?

[Alphecca1]

Hi all,

Autoland using CAT3B
The question is, when the aircraft “autolands” does it move the controls for you? If so what happens if the pilot moves the controls when the system is operating? What disconnect systems are in place? Is there a link to a website that will explain how currently autoland functions work?

Thanks in advance

[dwshimoda]

I think you'll find the answer is aircraft specific. Can't tell you for anything other than the B757, but yes, the controls move (yoke and throttles) - as they always do when the autopilot is in operation. As PF, you keep a light touch on both ready to take over should anything go wrong.

You can override the AP using the breakout function - can't remember the force required off the top of my head - but you are basically creating a highly unstable situation during a critical phase of flight.

Hope this helps.

DW.

[Northbeach]

When the aircraft “autolands” it means that the autopilot(s) is (are) engaged and that automation is manipulating the flight controls and the engines throughout the approach, landing, and in some cases roll out on the runway. “Autoland” means automation executes the necessary tasks to land the airplane. The pilot’s hands and feet are close by and “guarding” the flight controls.

The pilots are critical part of this autoland equation. It is not as though one pushes a “land now” button sits back and sips a good cup of tea. When the aircraft is in autoland mode, both pilots are in an extremely strict and scripted monitoring role. Most deviations from the strictly scripted autoland procedure will result in the crew exiting the autoland mode and discontinuing the approach.

If a pilot were to “move the controls when the system is operating” significantly in the opposite direction then in some cases the system would disconnect and warn the crew. By design during autoland operations my hands and feet are not manipulating the controls, the autoland system is (I am poised [as if the First Officer should it be necessary] to immediately take over from the autoland system should it fail or I wish to discontinue the approach/autoland landing).

Autoland is possible:

1. Then the airplane is manufactured and certified to perform the operation.

2. The company has an approved autoland policy in place (This requires specific maintenance, training and oversight).

3. The runway is approved for that airline’s specific autoland procedure.


The airport has the necessary equipment, lighting and its runway is certified for autoland. The weather is at or above the minimums required for the autoland approach procedure.

[dwshimoda]

on Northbeach's points:

The crew also need to be trained to Cat IIIB standards - there are very specific requirements for this and it is practised in depth in the sim.

The airport should be in lo-viz operations - this ensures that the protected area of the ILS is guaranteed.

Also, as I said, many of your points will be type specific. For example, I imagine (I don't know) that in an Airbus with sidestick, there would be no movement of the stick at all.

Cheers,

DW.

[Wizzaird]

For Airbus FBW there is no movement of the sidestick and no movement of the thrust levers during the autoland. If you move the sidestick and exceed the breakout force which is locking it in place the AP will disconnect and you wont be able to autoland :sad:

[Alphecca1]

thank you all very much for your replys :-)

[Northbeach]

thank you all very much for your replys :-)


You are most welcome, many of us enjoy answering them and appreciate your interest. Thanks for your business!

Respectfully,

Northbeach

[411A]

It should be noted that one aircraft (which has a dual/dual autoflight system, not triplex, as found on other aircraft) can perform an automatic approach/land (autoland) maneuver provided the specific runway is equipped with an Instrument Landing System, the approach chart does not specify that autolands are not authorized, and...the threshold crossing height (TCH) is at least 42 feet...without further restrictions...except unsuitable weather.

TriStar...first flight forty years ago, today.

[SNS3Guppy]

It should be noted that one aircraft (which has a dual/dual autoflight system, not triplex, as found on other aircraft) can perform an automatic approach/land (autoland) maneuver provided the specific runway is equipped with an Instrument Landing System, the approach chart does not specify that autolands are not authorized, and...the threshold crossing height (TCH) is at least 42 feet...without further restrictions...except unsuitable weather.

Same for the 747, except that we use 47' TCH.

Some Classics have triple autopilots, many just two, and two are required for autoland.

[Rick777]

the A320 only has 2 autopilots and auto lands just fine.

[Denti]

Same for the 737, only two autopilots, autoland and rollout are just fine, both on conventional ILS and the new fangled GLS thingy.