highflyer9790
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Autothrottle On Approach

Tue Feb 06, 2007 11:49 am

Hi all,
After seeing this pic

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Photo © André Costa - Lisbon Spotters


I was wondering-
looking at the autopilot controls, the AP is off, so the F/O is flying the approach manually. However, even though his hand is on the throttle, the A/T button is engaged (green light) and next to the FMS managed speed window, there is a dot indicating that it is engaged.

if this is correct, is the F/O simply waiting to take it off A/T or will he just let the A/T do its thing by itself? also, i know pilots like to fly manual approaches is conditions permit, do they also like manual speed?

If that is wrong, then is he overidding the FMS?

Thanks in advance!

highflyer wave 
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MD11Fanatic
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RE: Autothrottle On Approach

Tue Feb 06, 2007 12:39 pm

I notice many times that pilots will keep their hands on the throttle handles even with ATS engaged. One time I even saw a pilot giving the throttles a bit more of a push, apparently to get a quicker response than the ATS was going to. 737-300 I believe.

On the KC-10 too I've noticed the ATS is very slow to drive the throttle levers. I played around with ATS + N1 button with the throttles down at idle, and it took a good 20 seconds or more to drive them up to where the ATS thought they should be. Mind you, the engines were off so in essense nothing was occuring but the ATS still operates with or without the engines running.
 
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ThrottleHold
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RE: Autothrottle On Approach

Tue Feb 06, 2007 8:45 pm

This is a normal situation. The F/O is hand flying the aircraft with the autothrust engaged to look after the speed. Airbus recommend using autothrust for all approaches and it works quite well. The response time is definitely a lot quicker than on older Boeing systems.
Even with the autothrust engaged, it is important to keep your hand on the thrust levers on approach in case of the need to take over quickly.
 
wing
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RE: Autothrottle On Approach

Tue Feb 06, 2007 11:11 pm

Company SOP says hands on sidestick and AT during approach and take off.Thats because if you decide to go around you need to push the thrust lever or as in that picture the pilot will have to retard the TL's to reduce the thrust so the airplane can land.
No Auto system is(and can be) quicker than the human response.
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Starlionblue
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RE: Autothrottle On Approach

Tue Feb 06, 2007 11:20 pm

Am I right in saying keeping your hand on the throttles with A/T engaged is easier on the FBW Airbi? They do not move after all. What about Boeing? Do pilots still keep a hand on the throttle in these cases?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
PhilSquares
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RE: Autothrottle On Approach

Wed Feb 07, 2007 12:26 am

Quoting Starlionblue (Reply 4):
Am I right in saying keeping your hand on the throttles with A/T engaged is easier on the FBW Airbi? They do not move after all. What about Boeing? Do pilots still keep a hand on the throttle in these cases?

Yes, after flying both Boeings and Airbus it really is quite easy in both. In reality, the range of movement in the Boeing autothrottle system is pretty small.
Fly fast, live slow
 
highflyer9790
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RE: Autothrottle On Approach

Wed Feb 07, 2007 12:05 pm

Quoting Wing (Reply 3):
or as in that picture the pilot will have to retard the TL's to reduce the thrust so the airplane can land.

so, at some point before the flare, A/T will be disengaged?
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Starlionblue
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RE: Autothrottle On Approach

Wed Feb 07, 2007 1:10 pm

Quoting HighFlyer9790 (Reply 6):

so, at some point before the flare, A/T will be disengaged?

Yes. Betty says "retard, retard, retard" to indicate the point at which throttles should be brought to idle. The first two "retards" are verbs, the third is a noun.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CosmicCruiser
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RE: Autothrottle On Approach

Wed Feb 07, 2007 9:30 pm

Quoting HighFlyer9790 (Reply 6):
so, at some point before the flare, A/T will be disengaged?

Can't say about Airbus but on the MD-11/MD-10/DC-10 NO the auto throttles will retard themselves during or slightly before the flare. The MD-11 A/T do a much better job than the others which may require a little override for the best ldg. We have our hand on the throttles by 500' for 2 reasons. First, if you need to override them quickly you can and secondly, you have a good feel for what they're doing on the app.
 
highflyer9790
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RE: Autothrottle On Approach

Thu Feb 08, 2007 10:54 am

So although pilots like to hand fly an approach, they wont control the speed manually?
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Starlionblue
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RE: Autothrottle On Approach

Thu Feb 08, 2007 11:45 am

Quoting HighFlyer9790 (Reply 9):
o although pilots like to hand fly an approach, they wont control the speed manually?

Depends what you mean by manually. They do tell the plane what speed it should keep. But they don't adjust the throttles to achieve that speed. They let the autothrottles deal with it. At least that's the Airbus recommended procedure.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
highflyer9790
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RE: Autothrottle On Approach

Thu Feb 08, 2007 12:32 pm

Quoting Starlionblue (Reply 10):
Depends what you mean by manually. They do tell the plane what speed it should keep. But they don't adjust the throttles to achieve that speed. They let the autothrottles deal with it. At least that's the Airbus recommended procedure.

i mean full manual. although at the present moment i only fly cessnas, (not for long though  Wink) i would imagine that on a nice visual approach, the flying pilot would like the A/T off to deal with the speed by hand. No, the C152 doesn't have A/T,  biggrin , but even if it did i would enjoy manipulating the throttle myself...

can anyone see where im going?

thanks!

highflyer
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Starlionblue
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RE: Autothrottle On Approach

Thu Feb 08, 2007 12:35 pm

Quoting HighFlyer9790 (Reply 11):

i mean full manual. although at the present moment i only fly cessnas, (not for long though Wink) i would imagine that on a nice visual approach, the flying pilot would like the A/T off to deal with the speed by hand. No, the C152 doesn't have A/T, biggrin , but even if it did i would enjoy manipulating the throttle myself...

can anyone see where im going?

I did understand. Sorry if I was unclear. On the FBW Airbi the autothrottles are kept on as a rule even during a visual, manual approach.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CX Flyboy
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RE: Autothrottle On Approach

Thu Feb 08, 2007 1:38 pm

It depends what specific aircraft type. In our company the 744 fleet disconnect the autothrottles and provide thust manually. (Not sure how other companies do it on their 744s). On the 777 fleet, we fly with the A/T engaged, but override it as neccessary. The difference in procedure between the two fleets is because the 777 has a much larger margin for speed drops because of our efficient wing, and also the A/T is considered more agrresive and accurate than the 744s one.
 
CosmicCruiser
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RE: Autothrottle On Approach

Thu Feb 08, 2007 3:34 pm

Quoting HighFlyer9790 (Reply 11):
the flying pilot would like the A/T off to deal with the speed by hand

Most co.s, including mine, teach to fly the jet at the highest level of automation under most conditions. We do practice A/T off apps. in the sim and new guys get it on IOE but day in day out it isn't a good idea to "dumb down" the jet and hand fly w/ A/T off; you can get real preoccupied and your attention may not be where it should. We certainly had fly but keep the A/T on.
 
Airbus_A340
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RE: Autothrottle On Approach

Fri Feb 09, 2007 2:19 am

Quoting Starlionblue (Reply 12):
On the FBW Airbi the autothrottles are kept on as a rule even during a visual, manual approach.

Not sure if it is really a rule. In our company, we can choose to fly manual approaches with the A/T off. In fact, it seems to be a preference by some of our pilots in windy conditions to fly with manual thrust, since the human response time is quicker than the Airbus autothrust system.
People. They make an airline. www.cathaypacific.com
 
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ThrottleHold
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RE: Autothrottle On Approach

Fri Feb 09, 2007 8:50 am

Quoting HighFlyer9790 (Reply 9):
So although pilots like to hand fly an approach, they wont control the speed manually?

Airbus recommend leaving the autothrust engaged. However, 99 times out of 100 we fly it manually.
 
highflyer9790
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RE: Autothrottle On Approach

Fri Feb 09, 2007 10:28 am

thanks everyone!

highflyer
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Starlionblue
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RE: Autothrottle On Approach

Fri Feb 09, 2007 10:34 am

Quoting Airbus_A340 (Reply 15):
Quoting Starlionblue (Reply 12):
On the FBW Airbi the autothrottles are kept on as a rule even during a visual, manual approach.

Not sure if it is really a rule.

I think we have a slight translation problem. "As a rule" is an expression that means "mostly".
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
wing
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RE: Autothrottle On Approach

Mon Feb 12, 2007 4:29 am

Quoting Airbus_A340 (Reply 15):
Not sure if it is really a rule. In our company, we can choose to fly manual approaches with the A/T off. In fact, it seems to be a preference by some of our pilots in windy conditions to fly with manual thrust,



Quoting ThrottleHold (Reply 16):
Airbus recommend leaving the auto thrust engaged. However, 99 times out of 100 we fly it manually.

Interesting to hear this.I am not saying "wrong" but I would like to learn what would be the valid reason to use manual thrust although the makers of the airplane "recommends" to use the Auto Thrust.I couldn't get the reason of disengaging the AT in windy conditions when having "groundspeed mini" function.
follow me on my facebook page" captain wing's journey log"
 
jamesbuk
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RE: Autothrottle On Approach

Mon Feb 12, 2007 8:53 am

Is A/T kept on as a safety precaution so not to stall? Because if the pilot is concentrating on visual flying, he might not scan the inside instruments and might be close to a stall.

Rgds --James--
You cant have your cake and eat it... What the hells the point in having it then!!!
 
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Starlionblue
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RE: Autothrottle On Approach

Mon Feb 12, 2007 10:45 am

Quoting Jamesbuk (Reply 20):
Is A/T kept on as a safety precaution so not to stall? Because if the pilot is concentrating on visual flying, he might not scan the inside instruments and might be close to a stall.

Well, indirectly, sure. But I think a couple more things would have to go wrong before stalling is an imminent problem. Pilots don't regularly stall manually flown airliners with the autothrottles off, nor are they really in danger of doing so..

It's just one less thing to worry about.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CosmicCruiser
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RE: Autothrottle On Approach

Mon Feb 12, 2007 11:59 am

Quoting Jamesbuk (Reply 20):
Is A/T kept on as a safety precaution so not to stall?

No it's just that this is the way the jet was built and designed to fly. In the older jets you had no choice but now the A/T do a great job so let them do it. Rarely have I had to override the A/T on the MD-11. If you had to fly an app and ldg w/o A/T then ok pay attention and do it but day in day out why, as I said earlier, "dumb down" the jet.
 
MD11Fanatic
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RE: Autothrottle On Approach

Mon Feb 12, 2007 2:22 pm

Quoting CosmicCruiser (Reply 22):

Hey Cosmic, was that you landing at ONT today?? You almost made me crash my car on the 10 freeway because I was watching this UPS MD-11 landing at Ontario when I was driving home on the I-10 freeway from my army unit. Crazy headwind out there tonight eh?
 
CosmicCruiser
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RE: Autothrottle On Approach

Mon Feb 12, 2007 10:16 pm

Quoting MD11Fanatic (Reply 23):
Hey Cosmic, was that you landing at ONT today??

Hey MD11Fanatic, Nah, I'm home at the moment. I haven't seen ONT for a few years now but I remember nice layovers. Since I fly for the purple and orange guys I'll have to say be careful driving under those brown jets!  Wink
 
flymatt2bermud
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RE: Autothrottle On Approach

Tue Feb 13, 2007 2:07 am

Quoting HighFlyer9790 (Reply 6):
so, at some point before the flare, A/T will be disengaged?

Our A/T is programmed to reduce thrust to 'idle' at 50'. If it was set to hold V REF it makes for a near perfect landing in the touchdown zone at target speed.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
 
highflyer9790
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RE: Autothrottle On Approach

Tue Feb 13, 2007 9:34 am

Quoting FlyMatt2Bermud (Reply 25):
Our A/T is programmed to reduce thrust to 'idle' at 50'. If it was set to hold V REF it makes for a near perfect landing in the touchdown zone at target speed.

What aircraft is that? also, how big of a difference is there in approach speed (Normal, full flap, no ATC instruction) to flare speed in a jet?
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highflyer9790
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RE: Autothrottle On Approach

Tue Feb 13, 2007 10:38 am

Will A/T also if wanted apply reverse as well? i know (i think) this happens on CAT III approaches..
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CosmicCruiser
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RE: Autothrottle On Approach

Tue Feb 13, 2007 9:17 pm

Quoting HighFlyer9790 (Reply 27):
Will A/T also if wanted apply reverse as well? i know (i think) this happens on CAT III approaches..

No A/T will not apply reverse, even on CATIII the pilot is required to use reverse.
 
pjflysfast
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RE: Autothrottle On Approach

Tue Feb 13, 2007 11:21 pm

Quoting HighFlyer9790 (Reply 27):
Will A/T also if wanted apply reverse as well?

A/T will not automatically apply reverse thrust however, if FADEC equipped, the pilot flying may elect full reverse on touchdown and could basically leave the throttles there through rollout as FADEC will observe the reverse thrust limitations. Stow then go!
 
highflyer9790
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RE: Autothrottle On Approach

Wed Feb 14, 2007 6:44 am

Quoting CosmicCruiser (Reply 28):
No A/T will not apply reverse, even on CATIII the pilot is required to use reverse.



Quoting PJFlysFast (Reply 29):
A/T will not automatically apply reverse thrust however, if FADEC equipped, the pilot flying may elect full reverse on touchdown and could basically leave the throttles there through rollout as FADEC will observe the reverse thrust limitations. Stow then go!

Didnt know that.. now i do!
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pjflysfast
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RE: Autothrottle On Approach

Wed Feb 14, 2007 10:45 pm

Quoting Starlionblue (Reply 7):
Quoting HighFlyer9790 (Reply 6):

so, at some point before the flare, A/T will be disengaged?

Yes. Betty says "retard, retard, retard" to indicate the point at which throttles should be brought to idle. The first two "retards" are verbs, the third is a noun.

The third is a noun....."Who you talkin about Willis?"  Wink

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