Flying the 'Bus in manual thrust

[C_Star]

Been flying the '320 for 2 years now and discovered that, the final app/landing with A/T off tends to be trickiy. Every now and then I end up with a rougher-than-expected landing, have trouble with speed control (esp. in turbulence/thermals), get a "Pitch-pitch" warning etc.

I started wondering if:

- there is something inherent in the design of th 320, which makes flying with MAN THR more difficult. I am suspecting FBW/Autotrim and/or reduced natural speed stability, or

- this is due to my sh!te piloting technique and "rustiness" (it's SOP to use the the ATHR at all times, only occasionally we switch it off for training)

Any comments, observations, or hints?

Just before anyone starts a rant on "the children of magenta", or "200hr pay-to-fly wonderkids" - I have in excess of 6000 hrs in other types without ATHR and had no problems whatsoever flying them...

Regards,

C*

[Max Angle]

I suspect its lack of practice to be honest, if anything I have always found it easier in manual thrust than auto. Following our take-over and integration into another airlines operation we are no longer allowed to disengage the auto thrust in normal ops. so now I am lacking practice as well, always tried to use manual thrust whenever hand flying so rather miss it to be honest.

[Uplinker]

this is due to my sh!te piloting technique and "rustiness"

I commend your honesty. I find the Airbus quite easy to fly on manual thrust, and I am no Chuck Yeager!

However, if you are getting "Pitch Pitch" callouts on final approach; that's your problem right there. You are destabilising the flight path, which will affect your speed. I suspect when you get that sorted, your manual thrust approaches will become much easier. If your flight path is correct, the thrust should not need to be adjusted that much, except on very turbulent days.

Obviously, I'm guessing, (and I'm not a trainer), but maybe your instrument scan, or your glideslope tracking strategy need a bit of work?

Good luck!


U

[vilas]

C Star

In A320 the FBW computers resist any change in pitch androll that is not initiated from side stick or the FMGS although they cannotprevent completely. Therefore when thrust is increased or decreased the pitchup or down is markedly dampened. Also there is no feel in the stick toincreasing or decreasing airspeed. That is why initially flying Airbus you feelas if something is missing. Since there are no aerodynamic pressures transferredto the side stick visual observation is the only cue. It is a technique of Flyingwithout feel. Also if you bring thrust levers to idle then when you open thrustagain it takes close to 5 seconds before thrust comes up.

Initially one tends to over control, so hold the stick verylightly and when you make a change vertically do not disturb the lateral positionand vice versa. After getting the pitch or roll leave the side stick alone.Whenever you want to change speed create the trend arrow in the requireddirection by reducing or increasing thrust but do not allow the arrow to gopast the desired speed. Get out of idle thrust early and when on speed note theN1 or EPR. That is reference thrust from where you increase or decrease andcome back. When correcting speed first correct the attitude only then considerthrust change, Say flying level, unnoticed you start losing altitude the speed willincrease if you reduce thrust without correcting pitch then when you raise theattitude to maintain altitude the speed will drop. Few approaches with thisplan it will be OK.

[rudderrudderrat]

Hi C*,

get a "Pitch-pitch" warning etc.

It may be due to the speed decay during the flare is too much and you end up with a higher NU attitude. The attitude + rate of change of pitch is then very close to the trigger threshold for "Pitch-pitch" warning.

It may be that during manual thrust approaches, you are effectively taking the power off earlier than you are with autothrust engaged. (due to TLs at approach power position Versus being at climb gate with autothrust).

I have in excess of 6000 hrs in other types without ATHR

then close the TLs when you would do so on the other types.

[ZBBYLW]

Hi C-Star,

My airline encourages us to turn off all the magic when appropriate. I personally find that the airbus is a joy to fly with the magic off. The trick for me is my first month or so on the airplane I would study the power settings (just like the old Metros that I used to fly - I knew the power setting) so I knew what the airplane usually flies with. After that its just you fine tuning the rest.

When using the A/THR off I usually disconnect it when at THR IDLE with the AP off first. It's easier that way. Normally always before an ALT * for intercept. (In North America we are usually level for at least a bit on approach, if doing a constant decent then just match the thrust levers with the current thrust setting before turning it off.

With what ever speed you have selected you manage the power to maintain that (changes greatly with speed... usually in the 40-60% margin though depending on weights).

Once on the glide slope (or decent if visual, NPA etc..) Thrust idle almost always works unless the airplane is very light/heavy or the head wind is strong.

With F1 you may need to add a touch of power but the way I usually plan my approaches the airspeed is constantly decaying so with the speed going from 220-200 ish to 180 ish the Thrust usually stays very close to idle (if not idle).

At 2000 AGL I plan for flap 2 if speed is managed F speed is very low, but at the airports I usually fly into they want 170 or 180 to the FAF so at this point you usually have to add a bit of power to maintain the speed.

1500 AGL (or in IMC 2 miles before the FAF on a NPA) I go Gear Down and speed push. If it's an ILS and I am still a few miles from the FAF I would wait on managing the speed. At this point I will either maintain the thrust setting if it's low but if I am in a heavy plane (321, or heavy 320) go THR IDLE again.

1250 AGL Flap 3

1000 AGL Flap Full (If Required)

Somewhere around 600-900 the speed has decayed back to Vapp. About 5-10 kts above Vapp I slowly start increasing the thrust again and I find between 45-55% works in about 90% of the cases. A really light airplane, really heavy airplane or a strong headwind (or tailwind ) are the only real exceptions.

After slowly advancing the leavers to about 50% you can tweak it from there (the trend arrow makes this child's play). If your company wants you stable by 1000 AGL you can set F3 and F full earlier (or the rest if you like) my airline has me stable at 100+minimums or 500 on a visual.

Hope that helps. It's all technique no approach is the same. Also remember that you can decide when the power leavers come back the "retard" call is simply an auto call out and not a mandatory call out. Strong head wind or a F3 heavy landing (I usually only do a F3 if my Vapp is less than 140 if the runway is good length) and you may want to delay the "Retardation"

Cheers,
ZBBYLW

[IcePack]

Don't forget Ground speed mini. You are flying a variable airspeed, which is why Airbus say the auto thrust does a better job. Also as the thrust lever quadrant is very small compared to other types an inch of movement gives a greater thrust change than say an inch of movement on say a 767.

[C_Star]

Thanks for comments, Gentlemen.

Turns out it's mostly my crappy flying, but I think there's something with the Bus itself as well...

Vilas and IcePack have nicely verbalized what I had in my mind - neutral static stability, no pitch/power coupling and lack of tactile feedback on the stick due to FBW/Autotrim, plus having to chase a moving target (GS mini) with those little TL's...

Still, I think we have to be proficient enough to fly it properly... Thanks for hints, I'll try to get myself back in shape

[junebug172]

Not to be crass here, but everything posted here is nothing more than excuses.

I routinely fly the Airbus at Level 1 automation (all manual) with no problems. There's really nothing the Bus does that should throw you off.

It is, more than likely, you. Just keep practicing. Well more than half my approaches and landings are Level 1 and turn it all off going through 10,000'.

[oicur12.again]

There is no "in trim" position on the stick. That is, if you pitch to cater for a gust, it will auto trim you into that new position and you cant just let the stick return to the in trim position like on a conventional plane. I have always wished for 2 things on the bus, an auto trim off button and an increase in autopilot authority push button.

[EMIT]

Moving target

The trick of GS MINI is that it will decrease the need for thrust lever movements: with a positive gust, your speed instantly increases. With a stationary speed target, you would have to pull back power to stay on speed. With the increased target speed, there is no need to change power, you are still/again on target speed.

With a sudden negative gust, your actual speed, but also your target speed, will drop, so again, just maintain steady power.

In fact, with the thrust levers you are doing the same as on a Boeing, where you set a fixed speed target with sufficient margin above Vref and let the speed just bounce around with the gusts (keeping steady thrust), as long as speed deviations are not extreme of magnitude and/or duration.

[IcePack]

JuneBug,
Don't think anyone was making excuses. It just how it is, some find it no problem others do. As you, I don't find it a problem, just different. mind you the 330 is a s** in a strong gusty x-wind, nice challenge however. As for the little bus having taken both 75's & AB into GIB(a lot), the bus seems to handle better.

[sabenaboy]

Originally Posted by C-Star

it's SOP to use the the ATHR at all times, only occasionally we switch it off for training

I fly the A320 for one of those few companies where the training department understands that it's extremely important to keep the manual flight skills up to level. In my company manual flight (A/P, F/D and A/THR) is not only permitted, but trained from the beginning and encouraged whenever the situation permits it!

In my company it's done like this: Starting in the type-rating sim sessions the F/O's in training are learned to fly the Airbus manually (A/P, F/D & A/THR off) on many occasions whenever the exercise permits it. (And, for training, having one engine out is NOT a good reason to keep the A/P, F/D or A/THR) on. ) Then, during base training they'll fly a few touch and go's, again without any automatics. Later on, during the initial line training, they will be asked to fly manual raw data approaches, whenever the conditions permit it. Believe me, once they're fully released on line they'll handfly the A320 pretty well, or ... they won't be released on line.
Most of the time, I don't have to suggest my F/O's to turn the automatics off. they will have asked me before if they can. More often it happens, especially with the newly released kids, that I have to suggest them that it would be wise to fly with the automatics on when the metar warns us about low clouds and moderate visibility or when flying into a busy airport we are not familiar with! It's not that they are not smart enough to know that, it's just that they were so used to raw date flying during their training, that using the automatics for approach has become the exception, rather then the rule.

I'll admit that sometimes those new F/O's are not so great in using the automatics. For instance, the first time they have to intercept a G/S from above with the A/P, they will often have a problem. Not amazing, they've trained it once in the sim and then they were expecting it! So confronted to this situation these guys (and girls) will disconnect the A/P when it captures the initial approach alt before the G/S iso using the Airbus procedure for this. (dialling the altitude up and using V/S to get to the G/S.) Oh well, manually intercepting the slope and then re-engaging the A/P gets the job done just as well and it gives me something to talk about during a friendly post-flight debrief.

To get back to A/THR: I very, very, seldom use A/THR when flying manually. The same is true for all pilots in my company. I find that with the practise we have, all of us do a great job at using manual thrust and find that we can all do a better better job then the a/thr systems, especially in gusty and windy conditions. I tried landing a couple of times with A/THR in stormy conditions earlier in my A320 career and will now always use manual thrust in such conditions! (Just like all my colleagues and the training department agrees)

Conclusion: There's nothing special about using manual thrust on the Airbus. You are getting rusty!! Use every opportunity you get to practise! I'd invite you over to join our company to fly tourists down to the Greek isles during the summer season and share our experience. Unfortunately, that's not within my powers!

Good luck!

[Uplinker]

Perhaps you are used to different thrust lever quadrants and are moving the T/L's too far?

They usually only need a nudge rather than a push - I "waddle" them - (made up word !) - what I mean is holding them together, I turn my wrist slightly to waddle one forward 5mm, using the static one as a reference, then the other way to bring the other one level. If I need a bit more thrust I repeat the process. This way you don't accidentally push them along too far.

On flaring, I reduce the power immediately after I have flared, but before the sink onto the tarmac.

Lot's of different ways to skin a cat - these are mine.


U

[sabenaboy]

They usually only need a nudge rather than a push - I "waddle" them - (made up word !) - what I mean is holding them together, I turn my wrist slightly to waddle one forward 5mm, then the other way to bring the other one level. If I need a bit more thrust I repeat the process

I agree that it's very important in the A320 that there's not to much friction on the thrust levers. You shouldn't have to "waddle" them to make small adjustments. As soon as you push them, they should start moving without "chocks"
A few months ago an A320 joined our fleet, coming from an other company: the thrust levers were way to stiff to permit good manual thrust lever use. It took a few entries in the logbook and a personal chat with the technician to get the issue solved.

So if you need to "waddle" the thrust levers to make small adjustments: make a trouble report sheet!

[Fly3]

I agree with up linker that "waddling" them or "walking" them is the way to go. It allows for very fine adjustment and even MPL students have no problem with using that technique. Also use of the speed trend arrow is very helpful. As the tip of the arrow reaches the target speed waddle/walk the thrust levers to keep it there and the length of the arrow will decrease to zero leaving the power set exactly where it is needed.

[WhyByFlier]

Some tips for manual thrust on the A320:

- Target thrust (N1) for Vapp is approximately Gross Weight - 10. e.g. 60 tonnes requires about 50% N1.

- Never let the target speed arrow go through your target speed.

- The thrust levers on the Airbus are much shorter than on a Boeing or many other airliner types. The upshot of that is you don't have to move them as far to get the desired effect. Small movements to keep the speed - but accept the odd speed variation without changing the thrust. Fly like any other aircraft - pitch and thrust (power) = performance. Conf 3 target a pitch of 5 degrees (for a 3 degree approach) and Conf Full target 2.5 degrees.

- Aside from setting your approximate final approach thrust, when moving the thrust levers 'walk them up and down' (EDIT to say I just read uplinker's post - 'walk the thrust levers up and down' was the exact phrase used when I was trained) one thrust lever at a time with half centimeter movements to refine the speed whilst maintaining your speed.

- Anticipate your pitch changes and consider the wind.

- As for when you close the thrust - it's the same as with the ATHR on. Why would it be any different? Do you really believe 0.5 second makes a difference between a normal and a hard landing?

The Airbus 320 is an extremely enjoyable aircraft to fly MAN THRUST. With the greatest respect, any trouble you are having with landings as a result of flying MAN THRUST are down to you. Perfect practice makes perfect so keep doing it until you have it. Personally I practice at least once a week - at the very least.


In lufthansa - to keep commonality between fleets I believe their SOP is to disconnect ATHR if and when disconnecting AP.

[junebug172]

Glad you brought up walking the thrust levers.

Personally, I think that alone keeps you from over-controlling the power. Once you get it into the ballpark, barring any gusts, walking them back and forth should be enough.

[autoflight]

To avoid instability, strictly adjust the flight path with attitude and just make required thrust changes for speed control. The speed trend arrow is your friend and a great guide to the need for thrust adjustment. Of course there will be times when robust thrust changes are required.

[cosmiccomet]

I use to disconnect the A/T for most of my landings unless the ceiling/visibility is too low/reduced.
But I found that using selected speed in rough conditions is better than trying to chace the magenta Vapp.
Basically I am flying the Bus like a Boeing and works find for me.