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-   -   Flying the 'Bus in manual thrust (https://www.pprune.org/tech-log/514863-flying-bus-manual-thrust.html)

IFLY_INDIGO 18th May 2013 17:57

quality of my landings is much better with autothrust off. I feel more in control of the aircraft :O

keep practising. you may get the hang of the thrust lever management with practice. :ok: fly the wing with sidestick and keep the speed with thrust levers!

airbus_driver319 18th May 2013 19:04

How often does a FO get to land at indiGo?

Uplinker 18th May 2013 20:25


But I found that using selected speed in rough conditions is better than trying to chace the magenta Vapp.
Just out of interest, cosmic, would you care to explain that. How is it an improvement, and why do you consider it better than the Airbus method of fixed groundspeed rather than fixed airspeed?


U

cosmiccomet 18th May 2013 23:19

Because the ground speed mini in rough conditions could change a lot in a very short period of time so for me is better to have selected the Vapp (blue) and adjust the thrust as in a Boeing class aircraft.

Fly3 19th May 2013 00:02

Groundspeed minin is supposed to change a lot in rough conditions. That is the point of it.

vilas 19th May 2013 02:53

If you fly Airbus FBW with a Boeing cap you are creating problems for yourself. Instead of dragging previous practices and prejudices into the present aircraft one should study the flight controls chapter in detail to understand a/c behaviour. For instance if you flare above 50 ft the aicraft will auto trim, below 50 it won't and below 30ft it will pitch down so you need to maintain pressure. Airbus FBWs are stabilised platform a/cs. They need to be left alone after making required changes. I do not understand the logic of flying select speed in turbulent approach conditions. Why should you disconnect a protection which is devised for the very phenominon. Fly only Boeings Boeing way. Keeping ATHR on or off makes no difference to landings as long as you retard them soon after flare.

sabenaboy 19th May 2013 06:14


Originally Posted by cosmiccomet
But I found that using selected speed in rough conditions is better than trying to chace the magenta Vapp.

I also used to fly the B737 and then switched to Airbus (A320) and in my company I estimate that 95 % of all landings are made without A/thr. Personally I hardly ever use A/thr for landing, except for autolands of course.

We do a lot of manual flying in the A320 in our company (A/P, D/D and A/thr off), so I think we might say we fly the A320 "like a Boeing" but...

I believe it's not wise NOT to use the GS mini function especially in conditions where the magenta Vapp "could change a lot in a very short period of time in rough conditions" (sic).

I agree that while decelerating and configuring in stormy conditions (especially with A/thr on) it's not a good idea to do it in managed speed. Indeed the "gs mini bug" sometimes stays so close to the VNE for the config you're selecting, that a gust could quickly create an overspeed condition.

I would suggest you to always take advantage of the managed GS mini speed once you're below 1000' and in landing config. Combined with your "seat of the pants" it will give precious clues to dangerous conditions.

Using managed speed for landing does not mean you should foolishly chase the magenta bug when using manual thrust. Make a mental note of your personal "Boeing V app" if you want, but do no throw overboard the valuable information that gs mini variations give!

Uplinker 19th May 2013 09:07


Because the ground speed mini in rough conditions could change a lot in a very short period of time so for me is better to have selected the Vapp (blue) and adjust the thrust as in a Boeing class aircraft.
The whole point of the Airbus ground speed mini system is to react to gusts and keep the wing at a safe speed above the stall, while also keeping a constant groundspeed. Airbus fly constant GROUNDspeed on approach with a suitable margin above the stall, Boeing fly a constant AIRspeed only, (I don't know about 777 or NG).

Going to selected speed in an Airbus in such conditions switches off the groundspeed mini system and could be incredibly dangerous.

One should never override systems simply to make your flying task easier - especially if you don't fully understand or appreciate how they operate. The ground speed mini system was invented for a very good reason.


U

vilas 19th May 2013 10:24

sabenaboy
100s of pilots started with Airbus FBW and stayed with it, they don't need to know what you do in Boeing or other a/c. The ground speed mini is different philosophy to maintain energy levels in gusty conditions., If you are not going to use it in those conditions then there no point in using it at all. Trying to remember Boeing speed is neither here nor there because Boeing uses extra airspeed all the way while ground speed mini uses ground speed and keeps it constant. I never found any need to remember my 747 technique in A 320. If you add extra 15 kt to VLs as you are allowed the thrust variation will become less. If you are not comfortable due to conditions you should let the automation do the job but changing to some methods of your own thinking is not a very good idea, should you have incident you might find yourself very lonely.

sabenaboy 19th May 2013 11:58

Vilas, I don't understand why you're telling this to me. I think you're misunderstanding something: In my previous post I was telling cosmiccommet about the same thing as you were telling me ! :ugh:
So I agree with all you said in your post above.

However, you said one thing I do NOT agree with:

If you are not comfortable due to conditions you should let the automation do the job
My reply to that is: If one does not feel comfortable in a certain situation and needs to rely on automation to get the job done, one does not belong in the cockpit. ( I'm not talking about lowvis procedures of course, but, for example, about pilots who would be unable to cope with stormy conditions in manual thrust and need to rely on the a/thr to get the plane safely on the runway. In our company we are convinced that we, the pilots, do a better job in managing the thrust levers in gusty conditions, then the a/thr can. But I will always use GS mini guidance once I'm in landing configuration.)

vilas 19th May 2013 14:18

sabenaboy
What I am trying to say is practice manual by all means but whenever you are being pushed to limit by the environment let this time be, practice another time. I am not preaching but expressing another view point. See it this way, we hone our skills for that occasion when we will have a situation and the automation won't be there but to achieve that we should be carefull enough not to create an incident that would not have happened. For the same reason we practice most of the things in SIM and not in real aircraft. Afterall when the automation is to be used if not in trying circumstances? Any way if that is your company policy then I suppose nothing wrong in being loyal to pay check.

cosmiccomet 19th May 2013 15:43

I donīt see the point of using the ground speed mini without autothrust.
The ground speed mini exists only for Airbus aircraft and for Airbus aircrafts should be flown always with A/T ON...in the same way Airbus said that its aircrafts didnīt stall...

If all other aircraft manufacturers donīt use the GS mini and all those pilots who fly those aircraft donīt care too much about the GS during the approach so tell me why it is wrong to fly with MANUAL THRUST without using MANAGE SPEED.

Believe me that I understand very well the Airbus system...

rudderrudderrat 19th May 2013 16:16


all those pilots who fly those aircraft donīt care too much about the GS during the approach
Even on 707s we had INS wind readout and we flew an increased Vref based on the headwind component above the reported wind. The only difference is Ground Speed mini does it automatically.


Believe me that I understand very well the Airbus system...
Really?
Edit.
Please read http://www.airbus.com/fileadmin/medi...V_WX-SEQ02.pdf and tell us why you choose to ignore the minimum ground speed.
"Closely monitor the airspeed, speed trend and ground speed during the approach to detect any evidence of imminent windshear:
− A minimum ground speed should be maintained, to ensure a minimum level of energy to the aircraft, and to ensure proper thrust management during the approach, in case of sudden headwind to tailwind change. This is automatically performed on Airbus fly-by-wire aircraft by the Ground Speed mini function, when the speed target is managed and the A/THR function is engaged."

vilas 19th May 2013 16:23

cosmiccomet
The Airbus has recommended certain procedures to fly their aircraft. You need very good reason not to follow them. What Boeing says is Boeing's problem. A line pilot no matter how brilliant he is has exposure to only his environment and flight manuals provided to him, which are not enough to develop procedures. Airbus has access to the software, the hardware, wind tunnels, proto type test pilots and they receive incidents from all over the world. If operators face specific problems in specific situation the safe method is to refer to the manufaturer with possible solutions. Enhance your skils keeping the situation at hand in mind. I do not think in FBW aircraft, line pilots should change or device their own procedures because things are not as simple as they appear. I mentioned a fatal crash where if both FDs were switched off instead of only one 92 people would not have died. It is very easy to use a calculator not so easy to understand how it works. Now about your question, GS mini is a constant GS approach concept, if you use selected speed even with ATHR you are not flying with that concept, that's all. Boeing uses higher airspeed approach concept. You can keep building arguements for and against. Finally it is what you are comfortable with will matter.

Romasik 19th May 2013 17:31

I mostly fly this thing (330) on the approach without autothrust. And on many occasions without AP and FD. And I never had any problem. In fact I control speed better than AT, as I don't let it go all the way down to VLS (as AT does) and then apply too much thrust to recover. It's always much smoother.
Old habbits (747) die hard:) She has only two thrust levers, not four. Piece of cake:ok:

bubbers44 19th May 2013 18:00

I noticed our ground speed was lower than normal landing a 737 in LAS one day. It was the old 200 model so just cranked the speed up a bit. It was way before GPS. It worked but when we lost 20 knots at low altitude it would have been nice to have GPS GS to verify eyeball GS. Never had autothrottle in those days however. Eye ball GS indication works if you can see the ground.

Uplinker 20th May 2013 00:42


I donīt see the point of using the ground speed mini without autothrust.
Forgive me cosmic, but this seems the wrong way round. The point of ground speed mini is not to somehow enhance the autothrust, or give it something to do; it is to ensure that the aircraft has a minimum energy on a gusty day and a fixed groundspeed. What you seem to be saying is that you can't keep up with ground speed mini, therefore it is ground speed mini that is wrong, not you???

As others have said, the Airbus was designed by lots of very clever people and test pilots etc., are you really saying you are cleverer than all of them? If you fly an Airbus on approach with selected speed, you have disabled the groundspeed mini function and could find yourself near the stall at a very low level.



U

junebug172 20th May 2013 01:33

What's wrong with upping Vapp a few knots if you want more love and flying it manually that way?

Fly3 20th May 2013 02:37

Because thats like adding something for the wife and kids and is not very scientific. Groundspeed Mini is scientific and has always worked well for me.

junebug172 20th May 2013 05:30

Company procedure allows us to increase Vapp up to Vls + 15 as a windshear precaution.


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