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Autothrottle On Approach  
User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Posted (7 years 5 months 3 weeks 6 days 9 hours ago) and read 6298 times:

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 


121
31 replies: All unread, showing first 25:
 
User currently offlineMD11Fanatic From United States of America, joined Oct 2006, 81 posts, RR: 0
Reply 1, posted (7 years 5 months 3 weeks 6 days 8 hours ago) and read 6285 times:

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.


User currently offlineThrottleHold From South Africa, joined Jul 2006, 655 posts, RR: 1
Reply 2, posted (7 years 5 months 3 weeks 6 days ago) and read 6186 times:

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.


User currently offlineWing From Turkey, joined Oct 2000, 1559 posts, RR: 24
Reply 3, posted (7 years 5 months 3 weeks 5 days 22 hours ago) and read 6141 times:

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.



Widen your world
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 4, posted (7 years 5 months 3 weeks 5 days 22 hours ago) and read 6140 times:

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."
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 5, posted (7 years 5 months 3 weeks 5 days 20 hours ago) and read 6116 times:

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.


User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 6, posted (7 years 5 months 3 weeks 5 days 9 hours ago) and read 5925 times:

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?



121
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 7, posted (7 years 5 months 3 weeks 5 days 8 hours ago) and read 5903 times:

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."
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 8, posted (7 years 5 months 3 weeks 4 days 23 hours ago) and read 5837 times:

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.


User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 9, posted (7 years 5 months 3 weeks 4 days 10 hours ago) and read 5720 times:

So although pilots like to hand fly an approach, they wont control the speed manually?


121
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 10, posted (7 years 5 months 3 weeks 4 days 9 hours ago) and read 5700 times:

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."
User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 11, posted (7 years 5 months 3 weeks 4 days 8 hours ago) and read 5692 times:

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



121
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 12, posted (7 years 5 months 3 weeks 4 days 8 hours ago) and read 5691 times:

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."
User currently offlineCX flyboy From Hong Kong, joined Dec 1999, 6588 posts, RR: 55
Reply 13, posted (7 years 5 months 3 weeks 4 days 7 hours ago) and read 5677 times:

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.

User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 14, posted (7 years 5 months 3 weeks 4 days 5 hours ago) and read 5666 times:

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.


User currently offlineAirbus_A340 From Hong Kong, joined Mar 2000, 1560 posts, RR: 20
Reply 15, posted (7 years 5 months 3 weeks 3 days 19 hours ago) and read 5600 times:

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
User currently offlineThrottleHold From South Africa, joined Jul 2006, 655 posts, RR: 1
Reply 16, posted (7 years 5 months 3 weeks 3 days 12 hours ago) and read 5498 times:

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.


User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 17, posted (7 years 5 months 3 weeks 3 days 10 hours ago) and read 5481 times:

thanks everyone!

highflyer



121
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 18, posted (7 years 5 months 3 weeks 3 days 10 hours ago) and read 5480 times:

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."
User currently offlineWing From Turkey, joined Oct 2000, 1559 posts, RR: 24
Reply 19, posted (7 years 5 months 3 weeks 16 hours ago) and read 5318 times:

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.



Widen your world
User currently offlineJamesbuk From United Kingdom, joined May 2005, 3968 posts, RR: 4
Reply 20, posted (7 years 5 months 3 weeks 12 hours ago) and read 5281 times:

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!!!
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 21, posted (7 years 5 months 3 weeks 10 hours ago) and read 5263 times:

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."
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 22, posted (7 years 5 months 3 weeks 9 hours ago) and read 5250 times:

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.


User currently offlineMD11Fanatic From United States of America, joined Oct 2006, 81 posts, RR: 0
Reply 23, posted (7 years 5 months 3 weeks 6 hours ago) and read 5234 times:

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?


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 24, posted (7 years 5 months 2 weeks 6 days 23 hours ago) and read 5205 times:

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


25 FlyMatt2Bermud : 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 tar
26 HighFlyer9790 : 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?
27 HighFlyer9790 : Will A/T also if wanted apply reverse as well? i know (i think) this happens on CAT III approaches..
28 CosmicCruiser : No A/T will not apply reverse, even on CATIII the pilot is required to use reverse.
29 PJFlysFast : A/T will not automatically apply reverse thrust however, if FADEC equipped, the pilot flying may elect full reverse on touchdown and could basically
30 HighFlyer9790 : Didnt know that.. now i do!
31 Post contains images PJFlysFast : The third is a noun....."Who you talkin about Willis?"
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