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NO AUTLOLAND

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Roger... Thanks :happy:

 


John H Watson (retired 744/767 Avionics engineer)

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10 hours ago, Captain_Al said:

Yes, thus the limitation, so if you Autoland with Flaps 20 on the 400, you just violated a limitation, the jet will do it, but you are prevented from doing it by aircraft limitation, which pilots have to adhere to...

Flap 20 is not a 747 landing flap setting so why would Boeing certify flap 20 for autoland? NO AUTOLAND logic is not there to check the flight crew have set the flightdeck properly.


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1 hour ago, kevinh said:

NO AUTOLAND logic is not there to check the flight crew have set the flightdeck properly.

By regulation, you can't do a CAT III Autoland without the autobrakes working, either. The aircraft still doesn't stop you doing it . Of course, if your flaps are not set for landing, the aircraft will let you know in other ways.

You'd probably be surprised at how many systems use inboard (only) trailing edge flap position in their logic, yet don't bother to look at the ouboard trailing edge flap position. Would you still do an Autoland if only your inboard TE flaps were extended? Common sense applies.

It's a Boeing 747-400, not an Airbus. Pilots are still allowed to improvise :wink:

 


John H Watson (retired 744/767 Avionics engineer)

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So if I don't have auto brakes set to on I will not get a land 3 message?


Paul Grubich 2017 - Professional texture artist painting virtual aircraft I love.
Be sure to check out my aged cockpits for the A2A B-377, B-17 and Connie at Flightsim.com and Avsim library

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23 minutes ago, warbirds said:

So if I don't have auto brakes set to on I will not get a land 3 message?

Nope. John referred to regulations. Regulations and automation checks are entirely separate discussions (though they will occasionally reinforce one another). John was simply stating that, by regulation, the autobrakes must be working. By regulation, your landing lights must also be present and working in order to fly at night. You are not required to use them, however.

Nice paint work on the Connie, btw. I saw A2A posted something on Facebook either last night or early this morning. Looks good!


Kyle Rodgers

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2 hours ago, Qavion2 said:

By regulation, you can't do a CAT III Autoland without the autobrakes working, either. The aircraft still doesn't stop you doing it . Of course, if your flaps are not set for landing, the aircraft will let you know in other ways.

You'd probably be surprised at how many systems use inboard (only) trailing edge flap position in their logic, yet don't bother to look at the ouboard trailing edge flap position. Would you still do an Autoland if only your inboard TE flaps were extended? Common sense applies.

It's a Boeing 747-400, not an Airbus. Pilots are still allowed to improvise :wink:

 

Please don't start down that route even with a smiley. An Airbus won't stop you autolanding if you haven't set the autobrake either. If Airbus pilots really weren't allowed to improvise why bother having pilots at all?

There's a very good reason why aircraft don't just have a big "Autoland" button. Some controls must be manually set by the pilot according to the conditions. 


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2 minutes ago, kevinh said:

Please don't start down that route even with a smiley.

I don't see a reason to get upset about it. Airbus is a lot more automated than Boeing. It's just how they are, and there's no really right or wrong there.

Example: I was flying around in an Airbus 330 sim and the sim instructor said "all right, let's bring it back in." I went to kick the AP off and then reached for the throttles and was politely told off with "this isn't a Boeing - leave it alone and set the speed in the window." The guidance from Boeing is similar for the 777, though I'd argue that it isn't as strict as the leave-it-in-the-detent 330. Just a different approach to managing workload, and the associated human factors.

No reason you can't joke about it, though. I give my friends a hard time for having flown G1000s through their entire initial training. To me, flying steam gives you a better understanding of how things all come together. All the same, they can probably do many more cool things with glass than I can (and I still consider myself to know quite a bit about them), and if I had the choice of taking a G1000 up in the clag versus steam, it'd be the G1000 hands down.

...but I'm still gonna snipe at them for having that crutch the whole time. Luke knows. I gave him a world of a hard time for it, just because.


Kyle Rodgers

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5 hours ago, kevinh said:

Flap 20 is not a 747 landing flap setting so why would Boeing certify flap 20 for autoland? NO AUTOLAND logic is not there to check the flight crew have set the flightdeck properly.

LAND 3, LAND 2, and NO AUTOLAND logic is there to make sure you have the required redundancy required to make an autoland in Category II and III operations, it has nothing to do with the flight crew setting up the flight deck properly. The system is looking at the 3 FCC's, the 3 Radar Altimeters, the 3 ILS frequencies, etc to determine if you are Fail Operational , Fail Passive, or neither in which case you get NO AUTOLAND.

Your missing my point, you are restricted by limitation to Autoland with Flaps 25 and Flaps 30. The discussion was about whether the 747 could theoretically autoland with Flaps 20, and the answer is yes, nothing prevents it, except an aircraft limitation and yes, the fact that Flaps 20 is not a normal landing flap position. 

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5 hours ago, scandinavian13 said:

I don't see a reason to get upset about it. Airbus is a lot more automated than Boeing. It's just how they are, and there's no really right or wrong there.

Example: I was flying around in an Airbus 330 sim and the sim instructor said "all right, let's bring it back in." I went to kick the AP off and then reached for the throttles and was politely told off with "this isn't a Boeing - leave it alone and set the speed in the window." The guidance from Boeing is similar for the 777, though I'd argue that it isn't as strict as the leave-it-in-the-detent 330. Just a different approach to managing workload, and the associated human factors.

No reason you can't joke about it, though. I give my friends a hard time for having flown G1000s through their entire initial training. To me, flying steam gives you a better understanding of how things all come together. All the same, they can probably do many more cool things with glass than I can (and I still consider myself to know quite a bit about them), and if I had the choice of taking a G1000 up in the clag versus steam, it'd be the G1000 hands down.

...but I'm still gonna snipe at them for having that crutch the whole time. Luke knows. I gave him a world of a hard time for it, just because.

The problem as I see it is that it's an inaccurate joke. Good jokes are based on truth. People have the impression that Airbus is all automated and the pilot can't do anything about it. Of course they can, as you tried to prove in the A330 sim. Left to your own devices you would have succeeded. Yet the joke reinforces the false impression.

The 777 and 787 are just as automated as an Airbus.


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3 hours ago, kevinh said:

People have the impression that Airbus is all automated and the pilot can't do anything about it. Of course they can, as you tried to prove in the A330 sim. Left to your own devices you would have succeeded. Yet the joke reinforces the false impression.

I'm not surprised this "false impression" exists. During (Airbus) Normal Law operation (and even to a certain degree in Alternate Law), computers always sit between the pilot and the flight controls like a virtual nanny. Yes, Boeing 747-400s do have systems which help prevent excessive forces on control surfaces (and passengers), such as rudder ratio, aileron lockout and hydraulic relief valves, but it still doesn't stop the pilot doing something ill-advised like performing a barrel roll without having to push override buttons.

Autoland flare is only based on radio altitude. Even with the flaps in landing range, the autopilot doesn't know what flaps are selected (25 or 30) for the purposes of flare*. Probably the paper limitations are only placed on the flap positions because of excessive landing speeds (when the aircraft is heavy) and the fact that the engines won't be in high idle for go-around (High idle is active when the flaps are greater than or equal to 23 degrees).

* If both FMCs are inoperative, the autopilot does use flap position for computing minimum and maximum airspeeds for modes which use the elevator for speed control.


John H Watson (retired 744/767 Avionics engineer)

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12 hours ago, scandinavian13 said:

Nice paint work on the Connie, btw. I saw A2A posted something on Facebook either last night or early this morning. Looks good!

Thanks Kyle, it should now be available here at the Avsim Library. 


Paul Grubich 2017 - Professional texture artist painting virtual aircraft I love.
Be sure to check out my aged cockpits for the A2A B-377, B-17 and Connie at Flightsim.com and Avsim library

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19 hours ago, Qavion2 said:

I'm not surprised this "false impression" exists. During (Airbus) Normal Law operation (and even to a certain degree in Alternate Law), computers always sit between the pilot and the flight controls like a virtual nanny. Yes, Boeing 747-400s do have systems which help prevent excessive forces on control surfaces (and passengers), such as rudder ratio, aileron lockout and hydraulic relief valves, but it still doesn't stop the pilot doing something ill-advised like performing a barrel roll without having to push override buttons.

Autoland flare is only based on radio altitude. Even with the flaps in landing range, the autopilot doesn't know what flaps are selected (25 or 30) for the purposes of flare*. Probably the paper limitations are only placed on the flap positions because of excessive landing speeds (when the aircraft is heavy) and the fact that the engines won't be in high idle for go-around (High idle is active when the flaps are greater than or equal to 23 degrees).

* If both FMCs are inoperative, the autopilot does use flap position for computing minimum and maximum airspeeds for modes which use the elevator for speed control.

I wasn't talking about barrel rolls, just manual control of the aeroplane in normal operation. Your "joke" implied that Airbus is more automated with respect to autoland monitoring compared to a Boeing. That isn't the case.

You make it sound like the lack of high idle at flap 20 is part of the reason flap 20 isn't used for landing when in fact it's the other way around. The reason the engine uses a flap angle of 23 deg in the logic is because flap 25 is a landing setting and flap 20 is not. Flap 23 is also used in the landing configuration warning logic.


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Quote

You make it sound like the lack of high idle at flap 20 is part of the reason flap 20 isn't used for landing when in fact it's the other way around.

I don't understand what you are trying to say. I intended to say that the lack of high idle at flap 20 is part of the reason why flap 20 isn't used for landing.

You know I know how the aircraft operates, I know you know how the aircraft operates. Let's hear from others about how they interpreted my post. 

 

 


John H Watson (retired 744/767 Avionics engineer)

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On 29/03/2017 at 0:18 AM, Qavion2 said:

I don't understand what you are trying to say. I intended to say that the lack of high idle at flap 20 is part of the reason why flap 20 isn't used for landing.

You know I know how the aircraft operates, I know you know how the aircraft operates. Let's hear from others about how they interpreted my post. 

 

 

I understood what you said, and intended to say, perfectly well. Maybe I didn't make my explanation of why I disagreed clear enough. You said that the limitations on use of Flap 20 for landing were because of excessive landing speed when heavy (which I agree with) and the lack of high idle (which I don't), My point is that your second reason could easily be resolved by changing the flap microswitch position that enables high idle. So it isn't part of the reason why Flap 20 wasn't certified for landing. It is a consequence of Flap 20 not being certified for landing. Boeing could have set the high idle logic at any flap angle they chose. They chose to enable it at landing flap positions only.

As you know, the Flap 23 deg microswitch is there to tell the aircraft systems the aircraft is or is not in landing configuration. It controls the gear configuration warning logic (which sounds if you select landing flap with gear retracted). It also determines high idle. If Boeing had decided that the landing speeds at Flap 20 were acceptable they would have moved the landing flap logic microswitch switch from 23 degrees to, say, 18 degrees. The aircraft logic would be in landing mode at Flap 20 and have high idle would be set for go-around.


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4 hours ago, kevinh said:

You said that the limitations on use of Flap 20 for landing were because of excessive landing speed when heavy (which I agree with) and the lack of high idle (which I don't), My point is that your second reason could easily be resolved by changing the flap microswitch position that enables high idle.

Agreed, but then we move into the areas of fuel economy, noise abatement and also energy management (again).

By the way, there is no microswitch involved in high idle. The inboard trailing edge flap position sensors send signals to the Flap Control Units. At a specific flap position value, a logic gate/transistor provides a signal to idle circuits. Certain Flap Control Units provide signals to certain engines.

 

Cheers

JHW

 

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John H Watson (retired 744/767 Avionics engineer)

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